Lesson Notes By Weeks and Term - Senior Secondary School 3

SUBJECT:  BIOLOGY               

CLASS:  SS3

DATE:

TERM: 2nd Term

REFERENCES

• Modern Biology for Senior Secondary Schools by S.T. Ramlingam
• Essential Biology by M.C Michael 
• College Biology by IdodoUmeh
• SSCE, past questions and answers
• UTME, SSCE and CAMBRIDGE past questions and answers 
• Biology practical text 

WEEK THREE

ADAPTATION FOR SURVIVAL

CONTENT

• Competition and Types of competition
• Relationship between competition and succession
• Modes of adaptation
• Structural adaptation

COMPETITION

Competition is the process by which living organisms in the habitat struggle with one another for limited essential needs in the environment. Such scarce resources in plants include; light, space, nutrient and water while animals complete for food, space or mate. 

Competition finally results in survival of the fittest and elimination of the unfit. 

Types of competition 

1. Intraspecies competition: competition between organisms of the same species. e.g. many maize seedlings grown in a small area. 
2. Interspecies competition: that between different species of organisms. e.g. many maize and pepper seedlings growing in a small area. 

Relationship between competition and succession

Succession is the change in a population caused by the replacement of the old members with new ones as a result of competition. The newly formed habitat is gradually colonized by different species of plants in a stepwise manner until a relatively stable community is established and later the habitat will be inhabited by animals. As soon as a habitat is established, competition sets in. The early inhabitant modify the habitat by their activities while the later arrivals compete and outgrow the previous inhabitants which gradually loss out. 

EVALUATION

1. Define competition
2. Differentiate between intraspecies and interspecies competition.

ADAPTATION                              

Adaptation is the possession of special features which improve the chances of an organism to survive in its environment. All organisms have adaptive structures which could be structural or morphological and behavioural in nature. These enable them to live successfully in their habitat.  

There are three modes of adaptation:

1. Structural Adaptation 
2. Adaptive colouration
3. Behavioural Adaptation 

STRUCTURAL ADAPTATION 

This is a special modification of structures which help organisms to survive better in their environment. Examples include;  

1. Structural adaptation to obtain food e.g. a toad has a long tongue to catch its prey; birds have sharp, strong and curved claws for catching their prey; Insects have modified mouth parts for feeding; Insectivorous plants (e.gutriculariaspi.e. bladderwort, Droseriasp i.e. sundew, etc) have special structural adaptive features. 
2. Structural adaptation for escape and defence. Escape adaptation can be grouped into camouflage (concealing ccolouration), individual and group responses e.g. caterpillars taking the colour of leaves. Defence adaptation may be inform of physical structure e.g. spines and shell, scales etc, chemical defence e. g. snakes attack their enemies by spitting venom, bees and scorpion have stings and mimicry (looking like an uninteresting objects) e. g. stone plant.
3. Structural adaptation to attract matese.g. Adult male agama lizard displays its bright colour to attract its mates, flowering plants attract insects for pollination, bright coloured feathers of male domestic fowls and peacock etc.
4. Structural adaptation to regulate body temperature e.g. mammals have fat layer, sweat gland, feathers and subcutaneous fat in birds in birds etc. All serve to regulate heat loss. 
5. Structural adaptation for water conservation: e.g. some plants have small needle like leaves (conifers), thick bark (acacia), waxy cuticles etc to reduce the rate of transpiration. Likewise some animals possess scales, exoskeleton, feathers etc. to reduce water loss.

EVALUATION

1. Give three examples of structural adaptation for obtaining food in animals.
2. Give five examples of structural adaptation for escape and defence in animals and plants.

GENERAL EVALUATION

1. Define the following terms a) adaptation b) competition c) succession
2. Discuss the relationship between competition and succession
3. Differentiate between inter-species and intra-species competition
4. Give two examples each of structural adaptation in animals and plants for i) obtaining food ii) attracting mates iii) water conservation

READING ASSIGNMENT

College Biology: - Chapter 27, page 591 – 604

WEEKEND ASSIGNMENT

1. The following are scarce resources competed for by plants except A. light B. space C. mate D. water
2. Possession of special feature by an organism to improve its chances of survival in its environment is referred to as A. competition B. adaptation C. succession D. shading
3. Which of these is not a structural adaptation for protection A. mimicry in stone plant B. sting in bees C. shell in tortoise D. bright colour in cock
4. The following except one are structural adaptation for obtaining food A. thick bark in acacia B. long sticky tongue in toad C. modified beaks in birds D. sucker in mistletoe
5. The following are structural adaptation for conserving water in plants except A. shell B. conifers C. thick bark D. waxy cuticles

THEORY

1. Classify birds based on their structural adaptation for obtaining food
2. Give five examples of structural adaptation for obtaining mates