SS 2 BIOLOGY.

TUESDFAY 08/09/2020

CORRECTION TO TUESDAY CLASS ACTIVITY

1. Differences between dodder and mistletoe

dodder	mistletoe
It lacks chlorophyll	Possesses chlorophyll
Sends suckers to the phloem of the host	Sends its root  to penetrate  the xylem of the host
Absence of root	Presence of root

• a)Kingdom Fungi                                                                                                                                                                            b)Because :i.it lacks chlorophyll    ii.it stores excess food as glycogen    iii. The cell wall is made of chitin instead of cellulose in plants                                                                                                                           c)other four organisms in kingdom fungi are: i.Bread mould/mucor    ii.yeast          iii. Toadstool         iv. Rhizopus.
• a)Phylum Mollusca                b)Reasons: i.it has a large flattened  muscular  foot for movement       ii.it has tentacles that bear eyes.          Iii.it has a coiled calcereous shell.         Iv.it has soft unsegmented body.                  d)its mode of nutrition isSaprophic nutrition               e)economic important of snail: i. source of protein          ii.source of income  for the farmers         iii.its shell serves as source of calcium in animal feed

CORRECTION TO WEDNESDAY CLASS ACTIVITY

1. The purple colour of potassium permanganesecrystal gradually spread throughout the water in the glass jar because molecules of solute move from higher concentration to the region of low concentration until solution is uniform b)This process/ phenomenon is called Diffusion.
2. Two factors that will increase the rate of diffusion are:increase in the temperature of the solution , size of the solute and stirring or shaking of the solution.
3. In Volvox, each cell is connected to other cells to form a colony of cells shaped like a hollow sphere. In spirogyra, cells are connected to one another end to end to form filament.
4. Functions of the following organelles: a) Rough endoplasmic recticulum: it aids in transportation of materials within the cytoplasm b)Ribosome:it is the site for protein synthesis c)Mitochondrion: it is the power house of the cell. It is the site for energy production. d) Golgi apparatus: They in synthesis, packaging and distribution of materials. e) Centrioles: They are important in cell division.

ss 2

TUESDAY   01/09/2020

CLASS ACTIVITY

1. In tabular form, write three differences between dodder and mistletoe.
2. a) Name the kingdom to which mushroom belongs.                                                                                        b) State three reasons for your answer in (ia) above.                                                                                                                    c)Mention other four organisms that belong to the kingdom above.

d)State two economic importance of mushroom.

• Name the phylum to which Africa giant snail belongs.                                                                                                                   b) State three reasons for your answer in (2a) above.                                                                                                                         c)Explain briefly the role of Africa giant snail in nutrient cycling.

d) What is the mode of nutrition of the organism above.

e) State two economic importance of this organism.

WEDNESDAY      02/09/2020

CLASS ACTIVITY

1. a) Using the idea of concentration gradient, explain why the purple colour gradually spreads throughout the water in the jar, when potassium permanganate crystal is dropped into a gas jar of water.                                                                                                                                                                                                                       b) Name the biological phenomenon that occurred in the process above.       C) State 2 factors that will increase the rate of the phenomenon.
2. How is the organization in the spirogyra different from that of volvox
3. State the functions of the following organelles: rough endoplasmic reticulum, ribosome, mitochondrion, golgi apparatus, centriole and smooth endoplasmic reticulum.

Tue 25th 2020

CLASS ACTIVITY

1. Study from your textbook or from the internet, the structures of the red blood cells, white blood cells and the platelets. Based on your observations, list their features and comment on their composition in blood.
2. Red blood cells can change in shape. Explain the advantage of this characteristics
3. How do people in high altitudes adjust to low oxygen concentration of high altitudes?
4. Explain Phagocytosis
5. Outline the process of blood clotting

TUESDAY 18/08/2020

CORRECTION TO TUESDAY ACTIVITY

1. Respiration releases energy, which is required by the living organisms to carry out the life processes.
2. Aerobic respiration occurs in the presence of oxygen and releases a large amount of energy. Anaerobic respiration occurs in the absence of oxygen and releases a small  amount of energy.
3. Crossing over occurs at this stage.
4. Reduction division is important in organisms that undergo sexual reproduction in order to maintain the chromosome number of the species that is produced. It is necessary to produce haploid cell, so that one haploid cell from male and one from female fuses together to form diploid zygote cell.
5. Meiosis produces haploid gametes and this allow for the diploid number of chromosomes to be maintained when male and female gametes fuse. Meiosis also increase variation in the gametes produced. This increases the chances of survival during changes in the environment.

CORRECTION TO WEDNESDAY CLASS ACTIVITY

1. The spirogyra carries out sexual reproduction by conjugation in which two filaments come together. The male gamete from one filament moves to the other filament and fuses with the female gamete
2. Mitosis is important for the growth of an organism. In some organisms,. It  is important for the repair of worn out tissues of an organism. In some organisms, mitosis is important for sexual reproduction, e.g in flowering plants that reproduce asexually..
3. The paramecium has cilia which are fine, hair-like structures that move in a rhythmic and co-ordinated way so that the organism can move from one place to another. The Euglena has a long, whip-like flagellum  which moves in awave-like manner to enable the cell to move in water.
4. Stages in mitosis—In prophase stage, the chromosomes condense  and are visible under microscope. In the late prophase,, spindle fibres are formed and the nuclear envelop disappears. During metaphase,  chromosomes consisting of sister chromatids line up at the equator of the spindle. During anaphase,  chromatids are pulled apart to opposite poles of the cell. During telophase, the spindle fibres break down. The nuclear envelop and nucleolus reform.  

12/08/2020 WEDNESDAY

WEDNESDAY      

1. How does the spirogyra carry out sexual reproduction?
2. Explain the importance of mitosis in the life of a  mammal
3. Name and describe the structures that aid the paramecium and the euglena in locomotion.
4. Describe the stages in mitosis

11/08/2020 TUESDAY

TUESDAY   

CLASS ACTIVITY.

1. What is the importance of respiration to living organisms?
2. How does aerobic respiration differs from anaerobic respiration?
3. What occurs in  meiosis prophase 1?
4. Why is reduction division important in organisms that undergo sexual reproduction.
5. State the importance of meiosis in the life of animals.

CORRECTION TO LAST WEEK CLASS ACTIVITY

• 1 Animals living in the polar regions have thick body covering to trap body heat near their body surface , thus providing insulation. They have a layer  of body fat  called Blubber, which insulates them against  the cold.
• 2 Strata.
• 3. i). Flying squirrel: it possesses muscular membrane along sides of its body that enable  it to glide from tree to tree     ii)Tree  frog : it has toes with stick  pads that help it to grasp onto the tree branches        iii) gecko: it has friction pads on their feet to help them climb up the smooth  tree barks.
• 4. How plants and animals in savanna  are adapted to the environment conditions: Savanna experiences wet and dry season. During the dry season, water is scarce. Therefore many birds   and some nomadic animals  such as zebra ,buffalo migrate to regions  of plenty water .Their hoofed feet allow them to travel great distances.   Some animals like elephant in the trunk. Some animals remain  dormant in their burrows during dry season.                            
• The challenges that grassland plants face during the dry season are shortage of water and occurrence of  fires. Some savanna plants  such as baobab are fire and drought resistance. Baobab has a very large trunk to store water during the dry season and  the succulent bark also  contains resins  that protect  the tree from bush  fires.

Correction to Wednesday

1. Functions of the blood

i)It transports materials like digested food, hormones, waste products and heat around the body. This is performed by the plasma.                                                                                                                                       Ii)Transportation of the oxygen  by the Haemoglobin in the red blood cell.                                                                                                                   Ii) Production of the Antibodies  by the White blood cell                                                                                           iii)Clotting or Coagulation of blood   by the Platelets .

2. Differences between the artery and vein

Artery	Vein
Carries blood away from the heart	Carries blood towards the heart
Blood is under high pressure, hence it flows fast	Blood is not  under great pressure, hence it flows slowly and smoothly
Has no valve	Has valve to prevent flow back
Carries red oxygenated blood except pulmonary artery	Carries bluish-red deoxygenated blood except the pulmonary vein

3. Function of the following:

i. Pulmonary artery: it carries deoxygenated blood from the heart to the lung

ii. Pulmonary vein: it carries oxygenated blood from the lung to the heart

iii. Iilac artery: it supplies oxygenated blood to the pelvis, pelvic organs, reproductive organs, part of the thigh  and the lower leg

iv. Renal artery: it carries oxygenated blood to the kidney.      

WEDNESDAY 05/08/2020

1. State five functions of the blood, hence, mention the types of blood that perform the function
2. State five differences between artery and vein
3. State the functions of the following blood vessels    i)pulmonary artery    ii) pulmonary vein             iii)lilac  artery         iv) renal artery

TUESDAY 04/08/2020

CLASS ACTIVITY

1. Polar regions have characteristic animals such as polar bear, seals and penguins. Discuss the features that enable these animals to survive in  such temperatures. What is the purpose of these adaptations?
2. What is another name for different layers of a tropical rainfall?
3. Animals in rainforest have adaptations to help them move about. Describe the adaptation for each of the following organisms;  i) flying squirrel  ii) frog     iii) gecko
4. Explain how plants and animals have adapted to the environmental conditions in a savanna?

4/08/2020 TUESDAY

CLASS ACTIVITY

1. Polar regions have characteristic animals such as polar bear, seals and penguins.Discuss the features that enable these animals to survive in  such temperatures. What is the purpose of these adaptations?
2. What is another name for different layers of a tropical rainfall?
3. Animals in rainforest have adaptations to help them move about. Describe the adaptation for each of the following organisms;  i) flying squirrel  ii) frog     iii) gecko
4. Explain how plants and animals have adapted to the environmental conditions in a savanna?

CORRECTION TO TUESDAY ACTIVITY

1. a)  Cleistogamy is a condition in which ripe pollen grains are deposited on the stigma  which  becomes  ripened at the same time and it occurs in a flower which never open fully or some of the flower never open at all, the flowers are usually bisexual , so such flower can only undergo self-fertilization                                                                                                                             b.) 2 advantages;  i) pollen grains are not wasted          ii) it is a sure way of ensuring   pollination.

Disadvantages–i)it leads to production of weak offspring as a result of continuous or repeated self-pollination ii) the offspring or individuals produced are less adapted to the environment

2. The liver helps in  the regulation of the blood glucose level . When the glucose level rises after meal, the excess glucose is converted by the liver into glycogen under the influence of the insulin and stored. Likewise when  the glucose level in the blood falls during vigorous exercise or starvation, the liver converts the stored glycogen into glucose  under the influence of the glucagon for body metabolism.

CORRECTION  TO WEDNESDAY ACTIVITY

1. The placentation in specimens are;  Specimen A —Axile,,    Specimen B—Axile ,    Specimen C—Parietal,     Specimen D—Axile,, Specimen E—Marginal.
2. a) In the gill filament                                                                                                                                            b)In the gill rake

28/07/2020 TUESDAY

CORRECTION TO TUESDAY`S CLASS ACTIVITY

1. Oxygen debt refers to additional oxygen that is needed to convert lactic acid accumulated in the muscles during vigorous exercise or muscular contraction.
2. Differences between respiration and photoshnthesis
3. Gaseous exchange in Amoeba; Amoeba being a unicellular organism does not require a specialized organ  for gaseous exchange as simple diffusion is sufficient to meet the demands of respiratory processes in the cell. Amoeba has a large surface area to volume ratio, therefore, dissolved oxygen diffuse directly into the cell and carbon iv oxide diffuses out of the cell into the surrounding water through the cell membrane/ body surface.
4. Animal cell in high water potential/ hypotonic solution: Since the animal cell has low water, water enters  the cell by osmosis. As water enters the cell, it swells and it may burst because it has no cell wall. Example haemolysis in red blood cell.                                                                   Plant cell in high water potential: Plant cell behaves differently from animal cell when placed in hypotonic solution . Since plant cell has low water potential, water moves into the cell by osmosis. As water enters the cell, the vacuole increases in size and pushes the contents against the cellulose cell wall and becomes turgid. Plant cell does not burst because the cellulose cell wall is very strong and elastic
5. Animal cell in low water potential: Placing an animal cell in a hypertonic solution /low water potential , the cell having high water potential will lose water. As it loses water, it shrinks and becomes dehydrated and eventually die. The process is called Crenation. Example is earthworm in salt solution
6. Water potential is the measure of water to move from one place to another. It is used to described movement of water molecules.

CORRECTION TO WEDNESDAY ACTIVITY 1. a) Diffusion is defined as the movement of solute molecules from the region of higher concentration to the region of lower  concentration until it is evenly distributed.                         b) Osmosis is defined as the movement of solvent molecules(water) from the region of higher concentration of water(hypotonic /weaker solution) to the region of lower concentration of water (hypertonic/stronger solution) through a selective permeable membrane                                                                                                                                         c)Active transport is defined as the process in which energy is used to move particles of a substance  against concentration gradient from the region of low concentration to the region of higher concentration. Examples include: Absorption of dissolved mineral salts by the root hairs and absorption of amino acids by the cells of the small intestine of humans .

2.Active cells are usually small in size because they have large surface area to volume ratio, hence, they are able to obtain sufficient oxygen and food per unit time for their growth. Likewise, they can easily remove the waste products at a faster rate than lager cells.

3.Cells are unable to grow beyond their maxium size because it is important for them to have large surface area to volume ratio. Large cells have small surface area to volume ratio.Therefore, diffusion of food , oxygen and waste materials will be difficult and so waste matrials accumulate in the cells, likewise, food and oxygen cannot diffuse faster enough for growth. Eventually, large cell die

4. Tropism/. tropic movement:This is growth movement of plant part in response to an external unilateral stimulus and it is directl y dependent on the direction of the stimulus. Eg phototropism,, geotropism, hydrotropism

Nastism/nastic movement: this refers to the non-directional response of an organism to stimuli like touch, temperature, humidity. Eg Mimosa plant to touch.

Tropism	Nastism
Response leads to growth	It does not
Response is slow	Response is fast
Response is towards the direction of the stimulus	Response is not towards the direction of the stimulus
Movement is not easily reversed	Movement is reversible

CLASS ACTIVITY

1. a)Define cleistogamy       b)State 2 advantages and 2 disadvantages of self-pollination
2. The glucose level in the blood may rise after meal. It may fall during vigorous exercise or starvation . How can the body keep the blood glucose level constant? What is this process called?

WEDNESDAY  29/07 2020

1. Given the following specimens:                                                                                                                        Specimen  A- tomato         B-Orange         C-Pawpaw         D-Okra       E-Cowpea                               Mention the type of placentation found in specimen  A-E     
2. Study the structure of the gill of a tilapia fish  and answer the questions that follow   ; a)Where does the gaseous exchange take place?      b) Which of the structure removes the food particles  from the water that enters the mouth?                             

TUESDAY 21/07/2020

CLASS ACTIVITY

1. Explain  the term Oxygen debt and Tidal air
2. Highlight four differences between Respiration and Photosynthesis
3. How does amoeba carry out gaseous exchange?
4. Explain what happens to these cells in a solution with high water potential; a) animal cell    b) plant cell
5. Explain what happens to these cells in a solution with low what potential:  a) animal cell  b) plant cell
6. What is water potential?

WEDNESDAY  22/07/2020

CLASS ACTIVITY

1. Explain these terms: a) Diffusion      b)Osmosis           c) Active transport.                                                                        Hence, mention two importance of these processes each in living things

• 2. Explain why active cells are usually small in size
• 3. Why is it that cells are unable to grow beyond their maximum size?
• 4. Define tropic and nastic movement.  Hence, state four differences between tropic and nastic movement

 

15/07/2020 WEDNESDAY

CORRECTION TO TUESDAY CLASS ACTIVITY

1. Due to loss of a large amount of blood, the blood pressure in the glumerulus decreases. There will be a decrease in the rate of ultrafilration. This leads to kidney failure and cause waste materials to build up in the blood.
2. Osmoregulation is defined as the maintance or regulation of water to salt balance in the body fluild. Osmoregulation in Amoeba: Osmoregulation in amoeba is carrid out by Contractile vacuole. The contractile vacuole helps unicellular organisms to regulate the excess water in the cell. Amoeba being hypertonic to the surrounding water, water molecules will move into the cell via osmosis. If this excess water is not removed, the cell will under Cytolysis-bursting of cytoplasm. Therefore,excess water in the cytoplsm gradually enters the contractile vacuole. When it is full, it empties the contents into the water body,the process continues again.
3. When a body is dehydrated, the kidneys excrete less fluid and this results in a darker and more concentrated urine. Light-coloured urine indicates that the body is well-hydrated and the kidneys excrete more fluid as urine. This is osmoregulatoin and it regulated under the influence of a hormone called ADH.
4. The make-up of malpighian corpsule are Bowman`s capsule and Glumerulus.

CORRECTION FOR WEDNESDAY

1. The features of respiratory surfaces that make them efficient for gaseous exchange include: a) Respiratory surfaces are usually one-celled thick to shorten the diffusion distance and for easy diffusion. b)They have large surface area for easy diffusion of gases c)They are moist/wet for dissolution of gases d)They are highly vascularised( well supplied with blood capillaries) to bring in or take away diffused gases e) They are permeable to allow gases to pas in and out of them.
2. Alveolus is adapted for efficient gaseous exchange because: a)Alveolar walls are thin b) They are moist c)They are well supplied with blood capillaries- highly vascularised e) They are permeable
3. Gaseous exchange occurs in the stomata of the leaves.
4. Earthworm (annelid) carry out gaseous exchange by Cutaneous respiration.- via diffusion across the skin surface. Glands under the skin secrete mucus to keep the the skin moist. Oxygen from the atmosphere dissolves in the moisture linning the skin and diffuses across the skin surface into the blood capillaries found under the skin . Similarly, carbon iv oxide from the cells diffuses into the blood, and across the skin surface to surrounding.
5. Insects such as the grasshopper carry out respiration by means of tracheae which consists of a network of tubes that extends throughout the body of the grasshopper. The tracheae divide into smaller tubes called Tracheoles which come into contact with the body cells. Oxygen taken in by the grasshopper moves along the tracheae and traceoles, and enters the body cells.

. WEDNESDAY 15/07/2020

CLASS ACTIVITY

1. Explain how the features of respiratory surfaces make them efficient for gaseous exchange
2. Explain how the alveolus is adapted for efficient gaseous exchange
3. Where does gaseous exchange occur in the leaves of the plants?
4. How does the earthworm carry out gaseous exchange?
5. Describe the respiratory system found in a named insect

Tuesday. 14/07/2020

Correction to Wednesday class activity.

1. Five features/ characteristics of insect and wind pollinated flowers

Insect pollinated flowers/Entomorphilus flowers	Wind pollinated flowers/ Anemophi
Flowers are usually large, brightly coloured and scented to attract insects	Flowers are usually small, dull coloured and scentless thus not attractive to insects.
Nectar is often present to attract insects	Nectar is absent
Pollen grain is fairly abundant	Pollen is abundant
Pollen grains are large, sticky and heavy, usually with rough surface so that they can readily cling onto the insects	Pollen grains are small, dry,smooth and light, they are buoyant and easily blown about by air current
Stigmas are usually small and compact, not feathery and do not protrude. They are sticky so that pollen settling on them are not easily displayed	Stigmas protrude and are large and feathery so that they provide a large surface area to catch pollen floating in the air

2. Cross pollination is ensured in flowers due to : a) Dichogamy. b) Unisexuality c)Self sterility of that flower

3. Pollination in Hibiscus. Hibiscus has a brightly coloured petals to attract insects or birds which obtain nectar from the flower. Pollen grains adhere to the body of the animal, which transfers the pollen grains to the stigma of another flower.

Hello students, I congratulate you, if you have been following this platform from day one and also attempting all your class activities, likewise updating your corrections. I want to announce to you that ,we are done with 3rd term scheme of work. Henceforth, we will be attempting revision questions before we move on to SS 3 scheme of work.

CLASS ACTIVITY

1. During a car accident, a woman loses a large amount of blood. What effect is this likely to have on the process of ultrafiltration in her kidneys? What problems might this cause?
2. What is osmoregulation? Hence, explain osmoregulation in amoeba.
3. The darker the colour of urine, the more concentrated it is. Explain how you would monitor dehydrated your body is by examining the colour of your urine
4. What are the make-up of the Malpighian corpuscle?

Wednesday, 08/97/2020

Advantages and Disadvantages of Self poll in at ion

Advantages:

1. It ensure pollination esp. in bisexual flowers
2. It does not waste pollen grains

Disadvantages:

1. It leads to the production of weak offsprings as a result of continuous self pollination
2. Offsprings produced are less adapted to the environment

Advantages and Disadvantages of Cross pollination

Advantages:

1. It leads to production of healthier offsprings than self pollination
2. Offsprings produced are more adapted to the environmental conditions
3. It leads to the production of new varieties with good characteristics

Disadvantages:

1. It depends on external agents like wind, insects whose presence at right time may not be guaranteed
2. It may lead to waste of pollen grains esp by wind.

Major Agents of Pollination.

There are two major agents:

Wind and Insects

Hence, there are Wind Pollinated Flowers and Insect Pollinated Flowers.

Wind pollinated flowers.

Grasses are common examples of wind pollinated flowers. The flowers are usually small,massed in florescences which are dull in colour, scentless and without nectar.

Insect pollinated flowers.

The hibiscus plant is a good example of insect pollinated flowers. It is characterized by large, conspicuous (attracting) and trumpet-shaped flowers. It is scented and contains nectar(sugary substance).

Class Activity.

1. Write five features each of insect and wind pollinated flowers
2. List some ways by which cross pollination may be ensured
3. Describe the pollination of a named insect pollinated flowers

TUESDAY, 07/07/2020.

TOPIC: POLLINATION IN PLANTS.

Pollination is defined as the transfer of mature pollen grains from mature anther of one flower to the mature stigma of the same flower or of another flower of same species. Pollination is the first step in sexual reproduction in flowering plants.

Types of Pollination.

The types include:

a. Self-pollination: This is the transfer of mature pollen grains from mature anther to the mature stigma of the same flower or to that of another flower of same plant.

b. Cross pollination is the transfer of mature pollen grains from the anther of a flower to the stigma of a flower of another plants of same species.

Features of Pollinated Flowers.

Some plants have conditions or devices which aid self or cross pollination to occur.

Conditions or Devices that aid Self pollination:

1. HOMOGAMY: This refers to the ripening of anthers and stigmas of a bisexual flower at the time.
2. CLEITOGAMY: This is the condition in which ripe pollen grains are deposited on the stigma which becomes ripened at the same time.

Conditions orDevices for Cross Pollination:

1. DICHOGAMY: This is a condition in which the ripening of the anther and the stigma occurs at different time. There two types of dichogamy:

a. Protandry: This is the condition in which the anther of a flower matures earlier than the stigmas of that flower. So that that mature pollen grains are only useful to flower of other plants which have mature stigmas to receive them.

b. Protogyny: It refers to the conditions in which the stigmas of a flower matures earlier than its own pollen grains , so that it can receive only pollen grains from flowers of other plants.

2. Unisexuality: It is a situation in which some plants bear only male or female flowers. and not both on the same plants. E.g pawpaw. Such plants are monoecious plants.

3. Self-sterility: It refers to condition in which some plants make themselves sterile. The presence of pollen grains on their stigmas is injurious to further development of the plants.

CLASS ACTIVITY

1. What are Entomophilous flower and Anemophilius flowers?
2. State five differences between entomophilous and anemophilous flowers

WEDNESDAY, 01/07/2020.

Hi students

TOPIC: TYPES OF FLOWERS

Flowers are classified using the following pairs ofterms: complete- incomplete, bisexual-unisexual, radially symmetrical-bilaterally symmetrical. For example, a flower could be complete, unisexual and radially symmetrical.

Some flowers do not have the four whorl parts of floral parts i.e sepals, petals, androecim and gynoecium, they are called Incomplete flowers.

A bisexual or hermaphrodite flower possesses both the stamen and pistil. A unisexual flower has either the stamen or the pistil. A plant which possesses both male and female unisexual flower is said to be Monoecious e.g maize. However, if the male and female flowers are borne on seperate plants, the plant is called Dioecious e.g pawpaw.

PLACENTATION IN FLOWERING PLANTS

Placentation refers to the arrangement or position of ovules in the ovary. The ovules are found in the chambers called Loculi(loculus) which may be seperated from one another by partitions called Septa. The ovules in the chambers are attached to the placenta which can be found at the centre of the ovary or along the ovary wall.

Types of Placentation in Plants.

1. Marginal Placentation
2. Axile Placentation
3. Parietal Placentation
4. Free Central Placentation
5. Basal placentation

CLASS ACTIVITY

1. Study this diagram and answer the questions below;

a. Label the structures A-D

b. What bkind of placentation is shown above?

c. Give an example of fruit that shows the same type of placentation

2. Describe the following types of flowers;

a. Solitary flower

b. Perfect flower

c. Complete flower

d. Regular flower

e. Imperfect flower

TUESDAY, 30/06/2020

Hi students, have gone through the last corrections in order to correct your mistakes?.

TOPIC- REPRODUCTIVE SYSTEM IN PLANTS.

The reproductive structure of flowering plants is the FLOWER.

The flower contains the male and the female reproductive sex organs which enable them to carry out sexual reproduction. Fertilization occurs inside the flower and it leads to the develpoment of seeds and fruits. The seeds later germinate into new plants.

The Structure of the Flower.

The flower is the specialised shoot which bears the reproductive organs in flowering plants. It is a cluster of modified leaves which is borne on a shortened stem called flower stalk or pedicel. The flower is made up of four floral parts, namely;

1. The Calyx
2. The Corolla
3. The Androecium
4. The Gynoecium

PRIDE OF BARBADOS.

These flora parts are usually arranged in concentric rings, one above the other on the receptacle.

1. Calyx: It consists of the sepals which are usually small and green.

The outermost part or first part of the whorl of the flower is made up of three to five sepals. The sepals can be seperated of fused together.

2. The Corolla: These are the modified leaves known as the Petals. They are the second whorl or flora part in the sepals. They are the conspicuous part of the flower. They are usually brightly coloured  and scented which attract pollinators( insects).

3. Androecium: They are also called the stamens. They are the male reproductive organs. They are the whorl inside the petals. The stamen consists of the filament which bears the anther that produces the pollen grains. Flower may have three to numerous stamens which may be free or united.The anther is a 2-4 lobed structure. The pollen grains are produced in the pollen sacs. When the pollen grains mature ,the anther lobes split to release them. Pollen grains are fine yellowish particles.

4. The Gynoecium: It is called the Pistil. It is the female reproductive organ of the flower. It consists of one or more units called the Carpels. A carpel consists of an ovary, a Style and one or more stigmas. The stigma is a swollen structure at the end of the style which receives the pollen grains.The ovary contains one or more ovules. Within each mature ovule is a female gamete or an egg cell called the Ovum.

CLASS ACTIVITY

1. Mention five Essential and non essential parts of the flower.
2. Which flowers are called Perianths?
3. Differentiate between the following;

a. Polysepalous and Gamosepalous

b. Polypetalous and Gamopetalous

4. Mention three structural features of a pollen grain

5. After fertilization , what happens to the ovary and ovule?

CORRECTION TO WEDNESDAY QUESTIONS;

1. Gestation  period in human is 9 months (38 weeks)
2. Placenta and umbilical cord
3. Amniotic  fluid protects the foetus against mechanical injury.

23/06/2020

CORRECTION FOR TUESDAY

1. Internal fertilization is the fusion male and female gametes which occurs inside the female organism.,examples are mammals, birds, and reptiles . While external fertilization is the fusion of male and female gametes outside the body of female organism, examples are fishes and amphibians. They lay many eggs in aquatic environment to ensure that some of the eggs get fertilised and develop to become adult.
2. Viviporous animals are animals that develop their fertilised eggs inside the mother’s body. The embryo obtains the nutrients directly from the mother through the placenta, in addition to that present in the egg. They give birth to their young ones alive, examples are mammals. While ovoviviparous animals are animals that retain the fertilised eggs with the mother’s body until they are ready to hatch. Hatching occurs just before or as the eggs are being laid. After hatching the ‘live’ offsprings are released from the mother’s body. The embryo is not nourished by the placenta but instead obtains all its nutrients from the yolk present in the egg. Examples many aquatic organisms like shark, snake, some insects.
3. i. Vagina. ii. Oviduct/ fallopian tube iii. Uterus iv. Ovary/womb v. Uterus

WEDNESDAY   24/06/2020.

Hello students, hope you are staying safe.

Today’s sub-topic: Female Reproductive Gamete.

The female reproductive  gamete is the egg or ovum.  The egg is spherical and has a large nucleus containing one haploid set of of chromosomes. Abundant cytoplasm is present and may contain a small amount of yolk. The egg has a plasma membrane, which  in turn , is surrounded by an outer  membrane

FERTILIZATION IN MAN.

The egg released from the ovary is usually surrounded by a few layers of follicle cells. To penetrate the egg, the acrosome of the sperm releases an enzyme (lytic) to break down the corona radiata (membrane) and disperse the follicle cells. Only one sperm enters the egg. The haploid sperm nucleus fuses with the haploid egg nucleus and a diploid zygote is formed( fertilised egg). As soon as the sperm enters the egg , the membrane of the egg changes so that no other sperms can enter. The remaining sperms which do not fertilise the egg , eventually die.

Development of the Embryo.

fertilised egg passes along the oviduct to the uterus, and as it does so it begins to divide to form a hollow ball of cells called Embryo. It takes about five days for the embryo to reach the uterus. Eventually, the embryo sinks in or becomes embedded in the uterine lining. This is called IMPLANTATION. Embryonic membranes develop to enclose the embryo. A membrane called the Amnion encloses the embryo in a fluid-filled space known as Amniotic cavity.

CLASS ACTIVITY.

1. How long is the period of gestation in human?
2. Name two structures that link the foetus to its mother
3. How is the foetus protected against pressure from sudden movement of its mother’s body?

TUESDAY, 23/06/2020.

Hello students! Hope you are going through all your class activities.

TOPIC: REPRODUCTIVE SYSTEM IN VERTEBRATES.

Reproductive System involves all organs and glands that are concerned with reproduction in mammals. While reproduction is defined as the ability of living organisms to produce new individuals of their own species. It is one of the characteristics of life and its purpose is to ensure continuity of life. It ensures existence of species from generation to generation.

REPRODUCTION IN MAMMALS

Generally, vertebrates (mammals) are unisexual and reproduce sexually. Reproduction in mammals is viviparous I.e, they give birth to young ones that develops from fertilised egg.

Structure and Functions of male Reproductive System.

Structure and Functions of Female Reproductive System.

THE STRUCTURES OF MAMMALIAN GAMETES.

The reproductive sex cells are called the Gametes and they are produced in the Gonads. The formation of gametes is called Gametogenesis.

MALE GAMETES.

The male gametes or sex cells are called Sperms and they are produced in the testes by a process called Spermatogenesis. They are unicellular in nature.

Structure of a Sperm Cell.

The sperm cell consists of the head which contains the nucleus and the actosome, the middle piece and the flagellum. The structure of the sperm cell enables it to function effectively in fertilization in the following ways:1

1. Acrosome: It contains Lytic enzymes that dissolve the egg membrane and enhances the penetration of the egg during fertilization.
2. Nucleus: It contains genetic materials which fuseswith the nucleus of the egg or ovum
3. The middle piece: It contains numerous mitochondria which generate energy used by the sperm cell to move towards the egg.
4. Flagellum: It helps to move or propel the sperm cell.

CLASS ACTIVITY.

1.Compare internal and external fertilization.

2. List differences between Viviparous and Ovoviviparous

3. Examine the female mammalian reproductive system and name the structures responsible for:

i.The place where sperms are deposited during intercourse

ii . The place where fertilization occurs

iii. The structure where foetus develops

iv. The structure which produces the egg and hormones

v. The tube which carries urine out of the body.

4. Why are the tested located outside the body cavity?

Wednesday 17/06/2020

CONSERVATION OF NATURAL RESOURCES

IMPORTANCE OR BENEFITS OF CONSERVATION OF NATURAL RESOURCES:

Benefits of wild life resources conservation

1. It provides food for human consumption. e.g, meat, fish and egg.
2. It generate revenue for Government.
3. It can serve as tourist centers for pleasure and relaxation.
4. It provides research work for scientists.

Benefits of water resources conservation

1. It serves as sources of food supply, e.g, fish, prawns and cray fish.
2. It is used for hydroelectric power generation which provide s electricity, e.g kanji dam.
3. Water is useful for agricultural purpose. I.e. irrigation.
4. Water serves as a medium of transportation in Rivers, lakes and oceans. Etc.

Benefits of Forest resources Conservation

1.Forests are sources of food supply, e.g fruits, vegetables and meat.

2. Forests are sources of timber for construction purposes.

3. Forests provides medicinal herbs.

4. Forests provides raw materials for industries. E.g, Cotton, rubber, ropes, latex and timber. Etc.

Benefits of soil resources conservation

1. Soil support agricultural or farming activities.
2. Soil support forest and its resources.
3. Soil support wild life resources.
4. It is the home of some organisms. Etc.

Benefits of air resources conservation

1. Air provides oxygen used in respiration by plants and animals.
2. Air is the habitat of most organisms, e.g. birds and insects.
3. Air provides carbon dioxide used by plants for photosynthesis. etc.

Benefits of mineral resources conservation

1. Mineral resources provides fuel. E.g coal, petroleum and natural gas.
2. Mineral resources are used for industrial development. E.g. diamond, iron, copper and silver.
3. Mineral resources serves as sources of foreign exchange.
4. They provides employment for masses. e.g. miners, drillers and marketers. etc

Class activity:

1. Mention five ways of ensuring conservation of natural resources.
2. Mention five problems and difficulties associated with conservation of natural resources.

TUESDAY 16/ 06/ 2020

Hello students, hope you are staying cool and safe. Make sure you are attempting your class activities.

Correction on last week questions.

Aestivation: This is a period when many animals retreat into state of inactivity during the prolonged periods of high temperature and lack of water. These organisms become active again when the temperature is cool enough for them to carry out their activities. Examples:snail, crocodile lung fish etc

Hibernation: This is a state of sleep and greatly reduced metabolic activities that enables certain animals to survive prolonged cold winter as well as lack of food. Examples are bears and insect-eating bat.

Migration: This I’d the movement of certain animals from one place to new habitats where conditions are more favourable.

Mimicry: This is a suituation where one organism called mimic imitates another toxic or distasteful organism that displays warming colouration in order to protect itself from its predators.. This increases chances of survival.

Buoyancy: This ability of an organism to float freely in water or air.

Significance of hollow bones in birds and swim bladder in fish;

The hollow bones in birds are filled With air ,this makes them more lighter and buoyant in the air for flight

Swim bladder in fish is a long narrow tube or sac filled with air, this also makes them buoyant or float freely at any depth in water bodies

TODAY’S TOPIC : CONSERVATION OF NATURAL RESOURCES.

Conservation is defined as the protection and preservation of natural resources bin the environment. It is the judicious use or wise use of natural resources to ensure continuous availability and to preserve the quality or the original nature of the environment.

Types of Natural Resources.

A. Renewable Natural Resources: These are resources that can be easily recovered. E.g. water,air, plant, soil,wild life and forest.

B. Non-Renewable Natural Resources: These are resources that can not be easily recovered when exhausted. E.g. they are mainly mineral sales such as coal, petroleum, tin, gold, copper etc.

Reasons for Conservation:

1. To ensure the protection of plant and animal species and to prevent their extinction.
2. To prevent the destruction of of natural environment and to allow continuous use of natural resources for the benefit of man.
3. To promote the recycling of some scarce mineral resources
4. Natural resources like forest need to be conserved due to their medicinal use.
5. Conservation preserves the natural scenery and wildlife for people to appreciate and relax, providing one the aesthetic pleasures in life.

Class Activity.

From your textbook, study the methods of conservation of each of the natural resources mentioned above.

WEDNESDAY. 10/06/2020

SUB-TOPIC: ANIMAL ADAPTATION.

Adaptation of animals to Aquatic Habitat.

1. Possession of streamlined body for easy movement in water.eg fish,toad
2. Possession of fins for movement and webbed toes for swimming
3. Possession of gills for gaseous exchange in fish and toad
4. Possession of swim bladder for buoyancy (floating freely at any depth).

Adaptations of Animals to Terrestrial Habitat.

1. Possession of powerful limbs for movement . eg mammals
2. Possession of lungs for gaseous exchange eg mammals, birds,reptiles and amphibians.
3. Possession of sweat glant for excretion and cooling etc

Adaptations of Animals to Arboreal Habitat

1.Possession of wings for flight eg flight

2.Possession of hollow bones to make light eg birds.

3.Possession of streamlined body for easy flight etc.

Class Activity.

1 Find out the following adaptive terms and mention one organism that exhibits these adaptive features:

a.Streamline

b.Buoyancy

c. Mimicry

2.Explain the significance of hollow bones in birds and swim bladder in fish.

09/06/2020. TUESDAY

Hello students, hope you are still staying safe.

Correction on last class activity

1. Roles of decomposers:They enrich the soil with nutrients required by plant growth.

they break down complex organic matter in dead plants and snimals into simpler substances

They allow the ecosystem to function by enabling the recycling of nutrients.

2 . Farmers often plough leguminous plants into the soil so as to increase soil fertility. Nitrogen-fixing bacteria in the root nodules of leguminous plants can convert atmospheric nitrogen in the soil into ammonium compounds which are taken up by plants.

3. Denitrifying bacteria are microorganisms that convert nitrates into atmospheric nitrogen while nitrifying bacteria are microorganisms that convert atmospheric nitrogen into nitrates(soil nitrogen)

4. Nitrogen-fixation is the conversion of atmospheric nitrogen into soil nitrogen (nitrate).

Types of Association

2. Parasitism: Examples

Man and tapeworms

Mistleyoe and flowering plants

3. Commensalism : Examples

Remora fish and shark

Oyster and crab

Man and intestinal bacteria

4. Predation: Examples

Hawk and chicks

Lion and goat

5. Competition: Examples

Domestic fowl and chicks

Flowering plants and grasses.

Today’s work: ADAPTATION.

Adaptation is defined as the ability of a living organismto live successfully in a particular habitat as a result of its structure, function , appearance and behaviour. They are characteristics or traits that enable organism to survive and reproduce successful in response to changes in the environment.

Types of adaptations:

There are three type:

1.Structural adaptation: Examples of structural adaptation

a.Structural adaptation for obtaining food.

b. Structural adaptation for defence

C. Structural adaptation for securing mate

d. Structural adaptation for body regulation of body temperature etc.

2. Behavioural adaptation: Examples

a. Setting of a trap by ant lion

b. Overtaken prey by speed eg lion , tiger

c .Lying in ambush eg snake, praying mantis,

d. Remaining motionless e.g snail

e. Feigning death; eg millipedes and centipedes

f. Hiding eg rats

3. Adaptive colouration:

a .Warning coloration eg Wasp, lady bird(beetles),

b. Batesian mimicry: eg stick insect,grasshoppers, swallow tail butterfly,

c. Camouflage:eg grasshopper,,green snake,

d. Mating colouration

e. Countershading: fish

f. Rapid colcolour change/Concealing colouration :eg chameleon.

Challenge Activity:

1. Explain the terms with examples: aextivation, hibernation and migration.

June 3,2020

TOPIC; ECOLOGICAL MANAGEMENT.

Sub- topic: BIOLOGICAL ASSOCIATIONS

Learning Objectives: By the end of the lesson, students should be able to ;

i. Define different types of associations.

ii.Identify beneficial, harmful and neutral forms of association among organisms.

Definition of Biological association.

Biological associations are interactions that exist between two or more types of organisms. Association exists in different communities between organisms of different or same species. Association could be beneficial, neutral while others could be harmful.

TYPES OF ASSOCIATION

1.Symbiosis; This is a close association between two organisms in which both organisms benefit from each other.

CLASS ACTIVITY

Complete the other types of biological associations with four examples each

.

June 2,2o20.

Good day my always ready to learn students, hope you are enjoying your at home? Make sure you use your time wisely.

Correction on the last class activity.

1.Three processes that release carbondioxide into the atmosphere are;

i.Respiration.

ii.Combustion of materials.

iii.Decomposition of dead organic matter.

2.The burning of fossil fuels (petrol, wood etc) releases carbon dioxide into the atmosphere. This contributes to an increase in the atmosphere. If the amount of carbon dioxide released exceeds the amount taken in by plants during photosynthesis , this could disrupt the carbon-oxgyen balance.

TODAY`S SUB-TOPIC; WATER AND NITROGEN CYCLE.

Water Cycle

This is a cycle that describes the movement of water from the atmosphere to the earth and from the earth to the atmosphere.

Processes that release water into the atmosphere:

1.Evaporation from water bodies such as lake, sea ,pond etc

2. Evaporation from earth`s surface/land.

3.Transpiration from plants

4. Respiration from plants and animals

Process that return water to the earth`s surface (land and water bodies):

The only process that restore water back to the earth`s surface is through precipitation in form of rain, snow or hail. As water vapour evaporates into the atmosphere, it cools and condense into small water droplets, which falls to the earth as precipitation. Some of the precipitation falls back into the water bodies. Part of the precipitation moves into tiny hole or spaces in the soil. This is called Percolation.

Nitrogen Cycle:

Nitrogen cycle is defined as the processes by which nitrogen is constantly removed from the soil and restored back to the soil in form of nitrate.

Processes that return nitrogen into the soil: they are

1. Symbiotic nitrogen fixation by Rhizobium spp
2. Non-synbiotic nitrogen fixation by Clostridium and Azotobacter.
3. Electrical discharge by thunderstorm or lightning.
4. Ammonification/Putrefaction and nitrification.

Process that return nitrogen into the atmosphere;

The only process that restore nitrogen into the atmosphere is through Denitrification.

DECOMPOSITION

Decomposition is defined as the breakdown of dead plants animals into simpler subtances. The decomposers are fungi or bacteria that feed on dead remains of plant s and animals. There are two types of decomposers;

i.Micro-decomposers e.g microorganisms such as fungi and bacteria.

ii. Macro-decomposers e.g earthworm, millipedes, termites , mushroom,and snails.

Gases released during decomposition are ;carbon dioxide, ammonia, hydrogen sulphide and water vapour.

Class Activity

1.Mention two roles of decomposers.

2.Explain why farmers often plough leguminous plants into the soil

3.Differentiate between denitrifying bacteria and nitrifying bacteria

4. What is nitrogen fixation

5. Study the diagrams of water and nitrogen cycle.

NUTRIENT CYCLING IN NATURE.

Learning Objectives: By the end of the lesson, students should be able to:

1. Define Nutrient cycling.
2. Mention the various nutrients that are cyclic in nature.
3. Describe the processes involved in the carbon cycle, oxygen cycle, water cycle and the nitrogen cycle.
4. State the importance of nutrient cycle in nature.
5. Explain how decomposition is important in the cycling of nutrient in the environment.

Nutrient cycling

Nutrient cycling refers to the circulation of certain nutrients like carbon, oxygen, water,nitrogen in nature. They flow from environment to living organisms and are released back to the environment.

Carbon cycle

It involves various processes by which carbon is removed and restored to the atmosphere.

Process that removes carbon dioxide from the atmosphere :

The only process that removes carbon dioxide from the atmosphere is through photosynthesis. During the process of photosynthesis, the green plants absorb carbon dioxide from the atmosphere and use it to produce glucose.

Processes that Restore Carbon dioxide into the atmosphere:

1.Respiration

2. Combustion

3.Decomposition

OXYGEN CYCLE

Oxygen cycle involves the processes by which oxygen is removed and returned to the atmosphere.

Processes that remove oxygen from the atmosphere through:

1.Cellular Respiration

2.Combustion

3.Decomposition

Process that Restore Oxygen into the atmosphere:

Oxygen is released mainly through the process of Photosynthesis.

Note ,the processes of Respiration and photosynthesis keep the amount of oxygen and carbondioxide in the atmosphere relatively constant. However, due to human activities, the amount of carbon dioxide in the atmosphere has greatly increased.

Assignment

1.Mention three processes that release carbon dioxide from the atmosphere.

2. How does burning of fossil fuel affect the carbon-oxygen balance?

3. Study the diagrams of the following nutrient cycle:

a. Carbon cycle

b. Oxygen cycle

Keep staying safe.

No Fields Found.

Hello my students, its a great moment with you and i hope you will enjoy it.

I will like to revise on the topic- Microoraganisms. You all know the pandermic disease around the world now is covid- 19. A question for you- What is the difference between COVID-19 and CORONAVIRUS? .

Coronavirus is a microrganism (a virus) which causes a disease called Covid-19. While Covid-19 is a disease caused by a microorganism called Coronavirus , i.e Coronavirus is a pathogen\microoganism while Covid-19 is a disease .

Microorganisms are organisms that can not be seen with our naked eyes but with the aids of Microscope. They are everywhere -in the air, water ,in and on our body . in our food etc. Most diseases are caused by microorganisms. Although not all microorgainsms are harmful, some are beneficial to us, e.g Rhizobium spp. found in the root nodule of leguminous plants which help in nitrogen fixation.

There are five groups of microorganisms-Virus , Bacteria, Fungi, Protzoa and Algae.

STRUCTURE OF VIRUSES

Assignment -Study the structure of Viruses and Bacteria, then deduce the reasons why it has been very difficult to get COVID-19 Vaccine.

Likewise study modes of life of these two microorganisms and state three differences between them.

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GROWTH 12/05/2020

Hello my dear students, how has been your holiday? Its a great moment with you and you will enjoy it. I will like to revise a topic; Growth.

Growth is one of the characteristics of living organisms. For growth to occur the rate of anabolic must exceed the rate of catabolic reaction ie rate of building up must exceed the rate catabbolic processes.

Can you still recall examples of catabolism and anabolism?

Growth is defined as the increase in size or complexity of an organism due to the addition of new protoplasm.

Basis of Growth.

They are ;Cell Division, Cell Enlargement and Cell Differentiation.

Cell division ;it is the division of a single cell into two identical daughter cells. it results in an increase in cell number.

Types of Cell division;

Mitosis and Meoisis.

Mitosis ;is a cell division which involves duplication of chromosome whereby each daughter cell has exactly the same chromosome content as the parent. For multicellular organisms to grow , new cells must be synthesized by mitosis. For example ,skin cells must divide regularly to replace dead cells that have been shed from the surface of the skin. Dead cells are constantly being replaced by the process of mitosis. Mitosis results into two daughter cells.

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