This comprehensive guide for SS 3 Biology second-term revision focuses on essential topics, ensuring students grasp key concepts and prepare effectively for examinations. Topics range from heredity to adaptation for survival, with detailed explanations and likely examination questions for each.
Week 1: Heredity (Genetics)
Heredity is the transmission of genetic traits from parents to offspring. It explains why children resemble their parents. Genes, located on chromosomes, carry the instructions for traits such as eye color, height, and blood type.
Key Concepts:
- Genes: Units of heredity.
- Chromosomes: Structures that carry genes.
- Mendelian Genetics: Gregor Mendel’s experiments on pea plants laid the foundation for modern genetics.
Likely Questions:
- Define heredity and explain its importance.
- What are genes, and where are they located?
- Discuss Mendel’s laws of inheritance.
Week 2: Chromosomes
Chromosomes are thread-like structures found in the nucleus of cells. They are made of DNA and proteins and carry genetic information. Humans have 46 chromosomes (23 pairs).
Key Features:
- Structure: Composed of DNA and proteins.
- Types: Autosomes and sex chromosomes.
- Function: Carry hereditary information.
Likely Questions:
- What are chromosomes?
- Differentiate between autosomes and sex chromosomes.
- Explain the role of chromosomes in heredity.
Week 3: Variation and Evolution
Variation refers to differences among individuals within a species. Evolution is the gradual change in species over time due to natural selection and genetic variation.
Key Points:
- Types of Variation: Continuous (height) and discontinuous (blood type).
- Factors of Evolution: Mutation, natural selection, and genetic drift.
Likely Questions:
- Define variation and give examples.
- How does natural selection contribute to evolution?
- Discuss the significance of genetic variation in populations.
Week 4: Different Castes of Termites and Their Roles
Termites live in social groups with distinct castes that perform specific roles:
- Queen: Lays eggs.
- King: Mates with the queen.
- Workers: Build and maintain the colony.
- Soldiers: Defend the colony.
Likely Questions:
- Name the castes in a termite colony.
- What role does the queen play in a termite colony?
- How do soldiers protect the colony?
Week 5: Evolution
Evolution is the process by which species change over time. It is driven by natural selection, mutation, and environmental changes. Fossil evidence and genetic studies support evolutionary theory.
Likely Questions:
- What is evolution?
- Discuss the evidence for evolution.
- Explain the role of mutations in evolution.
Week 6: Theories of Evolution
Several theories explain evolution, including:
- Lamarck’s Theory: Inheritance of acquired traits.
- Darwin’s Theory: Natural selection drives evolution.
- Modern Synthesis: Combines genetics and Darwinian theory.
Likely Questions:
- State Lamarck’s theory of evolution.
- How does Darwin’s theory differ from Lamarck’s?
- Explain the modern synthesis theory of evolution.
Week 7: Process of Development of Zygote in Flowering Plants (Continuation)
The development of a zygote in flowering plants begins with fertilization, leading to the formation of an embryo. Key stages include:
- Fertilization: Fusion of male and female gametes.
- Embryogenesis: Development of the embryo.
- Seed Formation: Maturation of the zygote into a seed.
Likely Questions:
- What is fertilization in flowering plants?
- Describe the process of embryogenesis.
- How does a zygote develop into a seed?
Week 8 & 9: The Fruit
A fruit develops from the ovary of a flower after fertilization. It protects seeds and aids in their dispersal.
- Types of Fruits: Simple, aggregate, and multiple.
- Functions: Protect seeds, aid in dispersal, and provide food.
Likely Questions:
- Define a fruit and explain its functions.
- Differentiate between simple and aggregate fruits.
- What role do fruits play in seed dispersal?
Week 10: Adaptation for Survival
Adaptation refers to the traits that help organisms survive in their environment. Examples include:
- Structural Adaptations: Thick fur in polar bears for insulation.
- Behavioral Adaptations: Migration in birds to avoid harsh weather.
- Physiological Adaptations: Ability of camels to store water.
Likely Questions:
- What is adaptation?
- Give examples of structural adaptations in animals.
- How do plants adapt to survive in arid environments?
This expertly crafted guide equips students with a thorough understanding of second-term SS 3 Biology topics, ensuring confidence and readiness for examinations.