Lesson Note on Biology SS3 Second Term
SCHEME OF WORK
WEEK 1 HEREDITY (GENETICS)
WEEK 2 CHROMOSOMES
WEEK 3 VARIATION AND EVOLUTION
WEEK 4 DIFFERENT CASTES OF TERMITES AND THEIR ROLES
WEEK 5 EVOLUTION
WEEK 6 THEORIES OF EVOLUTION
WEEK 7 PROCESS OF DEVELOPMENT OF ZYGOTE IN FLOWERING PLANTS (CONTINUATION)
WEEK 8 THE FRUIT
WEEK 9 THE FRUIT (CONTINUATION)
WEEK 10 ADAPTATION FOR SURVIVAL
SS3 Second Term Biology Lesson Note
Below are the 2022 complete SS3 Second Term Biology Lesson Note
Week: 1
Topic: Genetics: The Science of Heredity
Introduction
All living organisms reproduce. Reproduction results in the formation of offspring of the same kind. A pea plant produces only pea plants each time it reproduces. A rat produces only rats. Humans produce only humans. However, the resulting offspring need not and most often do not totally resemble the parent. Several characteristic differences may occur between individuals belonging to the same species. The similarities and differences among the members of a species are not coincidental. Both the similarities and differences have been received from their parents. The mechanism of transmission of characters, resemblances as well as differences, from the parental generation to the offspring, is called as heredity. To learn more, Click here
Week: 2
Topic: Basis Of Heredity
Introduction
In a human, the normal chromosomes complement is 46, 44 of which are autosomes while 2 distinct chromosomes are deemed sex chromosomes, which determine the sex of an organism and various sex-linked characteristics.
In most animals, those who possess XX chromosomes are female while male animals possess an X and a Y chromosome. However, this is not true of all organisms, as it can be reversed in some species. A human’s sex is predetermined in the sperm gamete.
The egg gamete mother cell is said to be homogametic because all its cell possess the XX sex chromosomes. Sperm gametes are deemed heterogametic because around half of them contain the X chromosome and others possess the Y chromosome to compliment the first X chromosome. To learn more, Click here
Week: 3
Topic: Variation in Population
Introduction
A population is defined as a group of organisms of the same species living in a specified area within a given period of time. All human beings in one geographical area constitute a population of human beings. Also, all cowpea plants in one geographical area at a given time form the population of cowpea plants.
Variation is defined as the differences which exist between individuals of the same species. All members of a population have some characteristics in common, by which they can be recognized as members of the species. At the same time, members of the same species have individual differences. To learn more, Click here
Week 4
Topic: Evolution
Introduction
Organic evolution refers to the slow and gradual process by which living organisms have changed from the simplest unicellular form to the most complex multi-cellular forms that are existing today. Organic evolution primarily involves modifications in the existing organisms and the inheritance of these modifications.Biological evolution is genetic change in a population from one generation to another. The speed and direction of change is variable with different species lines and at different times. Continuous evolution over many generations can result in the development of new varieties and species. Likewise, failure to evolve in response to environmental changes can, and often does, lead to extinction. To learn more, Click here
Week 5
Topic: Behaviour Adaptation
Introduction
Behavioural adaptations are the way an organism behaves which helps it to survive in its environment. Behavior adaptations include activities that help an animal survive. Behavior adaptations can be learned or instinctive (a behaviour an animal is born with). Instinctive behaviour is a behaviour pattern that the organism naturally follows. Migration, hibernation and hunting behaviours are all behavioural adaptations that help an animal to survive in its habitat. For example, lizard hides under rocks to avoid gaining too much heat from the sun and survive in deserts.
Behaviour among the Groups:
- Aestivation:Some remain dormant during dry season (e.g. mud fish) or during a prolonged drought or during shortage of food
- Hibernation: This is when animals undergo dormancy especially in winter, during which metabolic rate is much reduced and the body temperature of homoeothermic species drops to that of the surrounding. Example is one found in bears, amphibians, reptiles and mammals. To learn more, Click here
Week: 6
Topic: Theories of Evolution
Theories of Evolution
The theories of evolution are attempts to explain how evolution have taken place. Two theories are explained below
Lamarck’s Theory of Evolution
Jean Lamarck a french zoologist was the first to suggest that organisms undergo evolution. His theory which was propounded in 1801 is also called the theory of use and disuse.
Lamarck’s contributions or postulates are as follows:
- that great changes in the environment result in corresponding changes in the species
- that these changes cause the organism to form new structures or habits to adjust to the new prevailing environment
- that organisms then develop specialised characters by use and disuse of organs. To learn more, Click here
Week: 7
Topic: Process of Development of Zygote in Flowering Plants (Continuation)
Germination in Dicotyledons
1. The primary root emerges through the seed coats while the seed is still buried in the soil.
2. The hypocotyl emerges from the seed coats and pushes its way up through the soil. The two cotyledons protect the epicotyl structures — the plumule — from mechanical damage.
3. Once the hypocotyl emerges from the soil, it straightens out.
4. The cotyledons spread apart exposing the epicotyl, consisting of the primary leaf (or leaves) and the apical meristem. To learn more, Click here
Week: 8
Topic: The Fruit
Introduction
A fruit is the ripened ovary or ovaries of a flowering plant, together with accessory parts consolidated with it, containing the seeds and occurring in a wide variety of forms and to some extent assists in the dissemination of the seeds.
Typically a fruit start to develop after that an ovule is fertilized as a result of the process of pollination, the ovary begins to enlarge. The petals of the flower drop and the ovule develops into a seed.
The ovary, together with accessory parts of the flower or other organs comes to form a structure surrounding the seed, which is the fruit. Fruit development continues until the seeds have matured. To learn more, Click here
WEEK 9
Topic: The Fruit (Continuation)
Dry Fruits
A dry fruit is the type of fruit in which the pericarp becomes dry, hard and woody or fibrous when the fruit ripens. Dry Fruits can be divided into those in which the seeds are contained in a seedpod of some sort which opens to release the seeds (called Dehiscent), and those in which there isn’t a seedpod which opens (Indehiscent).
Dry Dehiscent Fruits
Dry Dehiscent Fruits are the fruits which split to release their seeds when ripe, leaving the fruit walls on the plant. Dry dehiscent fruits are classified as: Follicle, Legume, Capsule, and Schizocarp. To learn more, Click here
Week: 10
Topic: Adaptation for Survival
Introduction
Adaptation is defined as the possession of special features or structure which improves the chances of an organism surviving in its environment. In other words, adaptation is a change in an organism that makes it to adjust or survive in its environment. Survival requires measures in terms of structure, reproduction, and other processes developed by the organism in other to withstand the hazard (or danger) and biological changes that exist in the environment. These is called adaptive features. To learn more, Click here
