Five

ADAPTATION 

Adaptation is the extent to which the structure and physiology of organisms make them live successfully in a particular environment. 

Adaptation of selected organisms

TILAPIA

1. Tilapia has streamlined body to move easily in water. 

2. It possesses paired fins (pelvic and pectoral fins) for steering, balancing and swimming and unpaired fins (tail, dorsal and anal fins) for stability in water. 

3. Swim bladder for buoyancy in water

4. Gills for gaseous exchange.

BIRD

1. Woodpeckers have long slender pointed beaks for picking up insects. 

2. Hawks, falcons, kites have powerful curved beaks for killing prey

3. Duck have serrated edge beak for sieving small food particles. 

4. Sand pipers have long narrow beaks for probing into the mud and sand.

TYPES OF ADAPTATION

1. Structural Adaptation

Structural adjustments are changes in a living organism’s structure to better adapt to an environment. Examples were given above. 

2. Behavioural Adaptation

Behavioural adaptation is the change in an organism’s behaviour in order to better survive in an environment. Examples are hibernation, aestivation, migratory flight etc. 

3. Physiological Adaptation

Physiological adaptations are a method of the brain that enables an organism to best survive/reproduce in a setting. These changes could be the various methods an organism reacts to the environmental stimuli. This includes shivering, sweating etc.

EXAMPLES OF ADAPTATION. 

1. ADAPTATIVE COLOURATION

A. Camouflage: The organism has the same colour as the environment e.g grasshopper

B. Warning colouration: The organisms have attractive colours that serve as a warning to predator's e.g brightly coloured lady bettle and toads. 

C. Mimicry: The organism resembles another object that the predator doesn't eat for protection e.g stick insect resembling a twig

D. Nest parasitism: Some birds lay their eggs in other bird's nest for protection e.g cuckoo bird

BEHAVIOURAL ADAPTATION

1. Movement in cluster (herd) to ward off animals e.g elephants

2. Nuptial flights to form new colonies e.g bees

3. Aestivation : A period of inactivity during long periods of drought or heat e.g lung fish

4. Hibernation: A state of sleep-like and greatly reduced metabolic activities during winter and period of food scarcity e.g bear. 

5. Dormancy : A period of minimal metabolic activity e.g seeds of plants and cysts of protozoa.

SOCIAL INSECTS

BEES

Queen bee: A fertule female with larger abdomen than workers. It lays eggs. 

Worker: A sterile female smaller than drone and queen. It builds cell (a room in the hive), collect pollen grain

Drone: A fertile male with wings. The drone mate with the queen during nuptial flight. 

TERMITES

1. Soldier: A blind, sterile wingless male that defend the colony. 

2. Worker: A blind, sterile wingless female, smaller than the rest, that build and repair ant-hill, feed the others and take care of the nymphs. 

3. Queen: A fertile wingless female which produce eggs. 

4. King: A wingless male that fertilizes the queen

PLANTS ADAPTATIONS

1. Hydrophytes: They live in water or water-logged soil. 

2. Mesophytes: They live on land where water supply is adequate. 

3. Xerophytes: They live in dry areas where water supply is limited. 

4. Halophytes: They live in where there's high salt concentration in water.

NUTRITION

Nutrition is the ability of living organisms fo feed. It is seen in two phases: catabolism and anabolism. 

Anabolism is the building up of new substances as seen in photosynthesis while Catabolism is the breaking down of complex substances e.g respiration. 

Nutrition can be divided into two:

1. Plant Nutrition

2. Animal Nutrition

PLANT NUTRITION

Photosynthesis is the process by which green plants manufacture their own food from carbon dioxide and water using energy absorbed by the chlorophyll from the sun. 

Light Stage

In the day, chlorophyll traps the solar energy and split water into H+ and OH- (photolysis). 

The hydoxyl ions give up its electron to the chlorophyll and form water and oxygen. Oxygen is then released as a by-product. 

ATP and NADP are formed. 

Dark Stage

These energy-rich molecules are used to reduce carbon dioxide to carbohydrates in a series of steps. 

MINERAL REQUIREMENTS OF PLANTS

1. Nitrogen - chlorophyll formation, protein and amino acids synthesis. 

2. Phosphorus - chlorophyll formation, root development, formation of ADP, ATP

3. Iron - formation of chlorophyll

4. Magnesium - chlorophyll formation

5. Potassium - cells formation, protein and carbohydrates synthesis

6. Sulphur - photosynthesis, growth

ANIMAL NUTRITION

They feed on food made by green plants and flesh of animals that consume them. 

Carbohydrates

Monosaccharides - glucose, fructose and galactose. They are all sweet and soluble in water. 

Disaccharides

Sucrose (cane sugar) - glucose + fructose

Maltose (malt sugar) - glucose + glucose

Lactose (milk sugar) - glucose + galactose

They are more soluble in water and sweeter than monosaccharides. 

Polysaccharides

Hundreds of molecules of monosaccharides joined together (condensed) with loss of water molecules. 

Starch 

Cellulose

MODES OF NUTRITION

1. Autotrophic/Holophytic Nutrition : 

It is divided into two:

A. Photosynthesis: Use of light energy to produce food

B. Chemosynthesis: Use of chemical energy to produce food. 

2. Heterotrophic Nutrition: It is divided into four:

A. Holozoic/Animal Nutrition: Ingesting food particles and breaking them down. 

B. Saprophytic Nutrition: Feeding on the remains of dead organic matter e.g mushroom

C. Parasitic Nutrition: Feeding on or in a body of another organism called a host. 

Endoparasites: in the body of the host e.g tapeworm

Ectoparasites: on the body of the host e.g flea

D. Symbiotic Nutrition: Two organisms supplement their nutritional needs e.g fungus and alga (lichen). Alga provides oxygen and carbohydrates and fungus provides water and minerals. 

Insectivorous plants are plants that derive their nitrogenous materials from insects. They trap them and feed on them. 

Examples are Sundew, Venus flytrap

Parasitic plants grow on another plants and derive their nutritional requirements from them e.g mistletoe. 

Epiphytes are plants that grow on another plants for support.