🐱 Cat Evolution Fun Fact!
Alishba, all domestic cats descend from the African wildcat (Felis silvestris lybica) — they were first domesticated about 10,000 years ago in the Near East. Cats have a special reflective layer behind their retinas called the tapetum lucidum — an adaptation evolved for hunting at night. This is why cats’ eyes glow in the dark! Every cat breed you see today is the result of both natural selection and artificial selection (Topic 4, Q5).
✏️ Worked Example — Read This First!
Explain natural selection using Darwin’s four conditions.
1
Variation.
Individuals in a population have different traits (e.g., some beetles are green, some are brown).
Individuals in a population have different traits (e.g., some beetles are green, some are brown).
2
Heritability.
These traits are passed from parent to offspring through genes.
These traits are passed from parent to offspring through genes.
3
Overproduction.
More offspring are born than the environment can support — there is competition for resources.
More offspring are born than the environment can support — there is competition for resources.
4
Differential survival & reproduction.
Individuals with traits better suited to the environment are more likely to survive, reproduce, and pass on those genes. Over many generations, the favourable trait becomes more common in the population.
Individuals with traits better suited to the environment are more likely to survive, reproduce, and pass on those genes. Over many generations, the favourable trait becomes more common in the population.
Natural selection: variation + heritability + overproduction + differential survival = change in a population over time.
💡 Remember: Natural selection acts on phenotypes (what you see), but evolution occurs through changes in allele frequencies in a population over generations.
EasyQuestions 1–3
Question 1 EasySee Answer →
What is evolution? What is natural selection? Who proposed the theory of natural selection and in what book?
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Question 2 EasySee Answer →
What is an adaptation? Give THREE examples of adaptations in animals and explain how each helps survival.
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Question 3 EasySee Answer →
What is the difference between homologous structures and analogous structures? Give one example of each and explain what each type of evidence tells us about evolution.
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MediumQuestions 4–7
Question 4 MediumSee Answer →
Explain the four types of evidence for evolution: fossil record, comparative anatomy, comparative embryology, and molecular biology (DNA). For each, describe how it supports evolutionary theory.
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Question 5 MediumSee Answer →
What is artificial selection? How is it different from natural selection? Give TWO examples of how humans have used artificial selection (e.g. dog breeding, crop plants).
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Question 6 MediumSee Answer →
Describe how antibiotic resistance in bacteria is an example of natural selection occurring today. Why is antibiotic resistance a major public health concern?
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Question 7 MediumSee Answer →
What is speciation? What is reproductive isolation? Describe TWO mechanisms that can lead to the formation of new species.
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HardQuestions 8–10
Question 8 HardSee Answer →
Explain the concept of Hardy-Weinberg equilibrium. What are the FIVE conditions required? If a population has 36% homozygous recessive individuals (aa), use Hardy-Weinberg to find: a) the frequency of the recessive allele (q), b) the frequency of the dominant allele (p), c) the frequency of heterozygous individuals (2pq).
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Question 9 HardSee Answer →
Compare convergent evolution and divergent evolution. Give one example of each. What does convergent evolution tell us about the relationship between an organism’s environment and its traits?
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Question 10 HardSee Answer →
Evaluate this statement: “Evolution is just a theory.” a) What does “theory” mean in science (vs. everyday language)? b) Name FOUR independent lines of evidence that support evolutionary theory. c) Is evolution considered settled science? Justify your answer.
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🌟 Great work, Alishba!
You have just traced the story of life on Earth — 3.8 billion years of change! Think about it: every cat breed, every Vocaloid character design, and even the yeast in your baking all share a common ancestor. Evolution is the thread that connects all living things. Tomorrow: Ecology!