ADAPTIVE COLOURATION AND BEHAVIOURAL ADAPTATION

ADAPTIVE COLOURATION

This is the possession by an organism of a colour which enables it to catch its prey, avoid its predators or enemies, secure mates and ensure their survival. Adaptive colouration may be grouped into

1. Concealing (cryptic) colouration to help organisms blend with their background and remain unnoticed by predators

1. Colour blendingwith the environment e. g. green cuticles of grasshopper, green snakes etc.
2. Counter shading by animals possessing a dark dorsal surface and light ventral surface as in tilapia fish to remain unnoticed by predator above and below.

• Colour change(camouflague)to match the environment as in chameleon, grasshopper etc.

1. Disruptive colouration as patterns to break the body outline of animals against the dark and light shades of their backgroung as in giraffe, leopard, tiger, lady bird beetle etc.

1. Warning colouration to announce the presence of the organism(s) to potential predator to avoid them because they have some unpleasant features e. g. variegated grasshoppers, black and yellow bands of wasps.
2. Mating colouration as in male agama lizard, peacock.
3. Mimicry in harmless organisms resembling a distasteful or harmful one for the enemies to avoid such e.g. stick insects, swallow tail butterfly.
4. Bright colouration of insect pollinated flowers and pitchers of insectivorous plants.

 

EVALUATION

1. Give five types of adaptive colouration in animals.
2. Give five examples of animals and their adaptive colouration

 

BEHAVIOURAL ADAPTATION

Behaviour is basically adaptive, everything used by organisms to promote their survival. Examples include:

1. Behavioural adaptation in predators e.g. Lion with high speed chases its prey; spider spins its webs for its prey
2. Behavioural adaptation to protect prey from predators e.g bats hold tree branches with heads upside down (which is described as swaying in the air), Antelopes escape with speed, beetles secreate offensive odour, toad puffs itself up
3. Behaviuoral adaptation for avoiding harsh weather conditions e.g. aestivation e. passive period of existence. It is practiced by crocodiles; Hibernation i.e. sleep period to survive food scarcity or winter (low temperature) exhibited by insect-eating bats; migration of certain animals (e.g cattle egrets) to favourable habitats
4. Behavioural adaptation in plants: e.g some plants shed leaves in dry season (deciduous plants); some like yam tuber, potatoe die down and survive as underground stem; plant seeds can remain dormant, plant shoot moves towards light (Positive phototropism)
5. Gregarious behaviour (movement in groups) is expressed by elephants zebra, birds, fishes, social animals (bees, termites) etc.

 

EVALUATION

1. Define hibernation and aestivation
2. Give four examples of animals and their adaptation to escape from predators.

 

SOCIAL ANIMALS

Social animals are those in which individuals of the same species live together cooperatively in organized communities known as societies (colonies). Examples of social animals are: social insects (like termites, honey bees or wasps, ants etc), wolves, foxes, baboons etc.

Characteristics of Social Insects

1. They live together
2. They display division of labour
3. They show distinct castes
4. Members communicate with one another within the colony.

 

TERMITES

Habitats of termites: They are found living together in large communities in nest which may be tunnels in dead wood or ant hills (termitaria).

Note- Termites are blind: they communicate through touch and smell.

 

Castes of termites:

They have three castes: The reproductive, soldiers, workers.

1. The reproductive are of three types: king, queen and winged reproductive. The king has no wing, is smaller than the queen and it fertilizes the queen. The queen has a small head, small thorase and large abdomen. It is the largest of all the castes. Only one queen at a time is found in a colony. The queen lays eggs. The winged reproductive are fertile and are potential kings and queens of new colonies.
2. The soldiers are sterile, wingless and blind. They have big heads with stony maxillae and mandibles. Soldiers are of two types: (i) The mandibulate soldiers with strong mandibles and (ii) Nasute soldiers with projective mouth paths. The soldiers defend the colony against enemies.
3. The workers are wingless, blind, and sterile. They form the majority in the colony and possess well developed mouth paths. They build and repair the termitaria; provide food for colonial members; look after the eggs laid by the queen and baby termites (nymphs).They feed the nymphs and the queen and cultivate fungus gardens.

 

Life history of termites

Termites exhibit incomplete metamorphosis i.e.

Egg                   nymph                     adults

The nymphs develop into soldiers and reproductive. And those which fail to develop become workers. When the winged reproductives are mature, they exhibit nuptial or wedding flight i.e. swarming out from the existing colony to build new ones.

 

Behavioural adaptation of termitesfor survival

1. They move in groups to ward off their enemies
2. They have a wide variety of diet; feeding on both living and dead plants.
3. They burrow into the soil or wood to build tunnels for protection against their enemies.
4. The habit of feeding on dead members helps to keep the colony clean.
5. Their ability of massive production of off springs promotes their survival.

 

Economic importance of termites

1. Termites while building their tunnels help in loosening and mixing the soil.
2. They decompose wooden materials as they feed.
3. They add humus to the soil through their decomposition activities.
4. They act as good source of protein and fat.
5. The ant hill clay can be used to build the surface of tennis court.

 

EVALUATION

1. Mention the three castes of termites and their functions.
2. What are the characteristics of social insects?

HONEY BEES

Habitat of Honey bees – These are social insects living in hives made up of chambers or cell.

Castes of honey bees

The bee colony has 3 castes, namely:

• The drone (in hundreds per colony)
• The queen (only in 1 per colony)
• The workers (in thousand per colony)

1. The drone is the winged with shorter abdomen than the queen but bigger than the workers. The drone mates with the queen during the nuptial flight after which it dies.
2. The queen is a fertile female, winged and much bigger than the workers. It is fed with royal jelly and lays egg.
3. The worker is a sterile female, winged and is smaller than the queen or drone. It possesses eyes and a sting. Also with modified mouth paths for collecting nectar and building the hive. The workers legs are also modified for collecting pollen grains from flowers. The workers perform a special dance called rail wagging as it locates a food source. The workers secrete wax for building the hive, ventilate the hive and clean the cells, guard the hive, make honey from nectar and pollens and feed the larvae with royal jelly or honey.

 

Economic importance of honey bees

1. They help to pollinate flowers.
2. They produce honey which has high nutritive and medicinal value.

 

EVALUATION

1. What is tail wagging in a beehive community?
2. Mention two economic importance of honey bees.

 

GENERAL EVALUATION

1. Use snakes and flowering plants to describe structural adaptation.
2. Illustrate adaptive colouration using two examples each for plants and animals.
3. Use aestivation, hibernation and migration to describe bahavioural adaptation.
4. What are social animals? State two attributes of social animals
5. State the castes involved in a termite community
6. State the three types of reproductives present in a typical termitarium
7. What is nuptial flight?Which caste undergoes nuptial flight?
8. State three ways by which termites are relevant to life in the society.
9. State the castes involved in a beehive and their roles.
10. What is tail waggling? Which caste performs tail waggling?

  

WEEKEND ASSIGNMENT

1. The following except one are behavioural adaptation mode to avoid harsh weather condition A. aestivation B. swaying C. hibernation D. migration
2. Concealing colouration exhibited by some organisms to remain unnoticed is referred to as A. mimicry B. hibernation C. camouflage D. wagging
3. The following except one are social animals A. fowl B. honey bee C. ants D. wolves
4. What king it to a termitatium is what _____ is to a beehive
5. Which of these group of animals does not exhibit gregarious behaviourA. termites B. lions C. zebras D. snakes

 

THEORY

1. State the roles of the castes found in: (a) a termitarium (b) a beehive
2. Differentiate between aestivation and hibernation.

 

See also

ADAPTATION FOR SURVIVAL

VARIATION IN POPULATION

FRUIT

GROWTH

ECOLOGICAL