1. I know that fossils found in the lowest geological strata are generally the m

Question

1. I know that fossils found in the lowest geological strata are generally the most primitive. Can you explain why they would not be advanced, complex, widespread and specialized?

2. When a population goes through a bottleneck, genetic drift is likely to occur. Why would it not be mutation rates increase, extinction rates decrease, natural selection decreases in intensity, mutation rates decrease?

3. Geographical barriers are NOT necessary for sympatric speciation, why?

4. Sympatric speciation through polyploidy has been a frequent phenomenon in the evolution of plants. Why is it not for insects, mammals, bacteria and fish?

5. I know none of these can be called adaptations, but you you explain why to me? tomatoes in salty areas that store salt in their leaves, spines and thick cuticles on cactus, and white fur in polar bears.

Explanation / Answer

1) Fossils found in the lowest geological strata are the most primitive and the oldest. This is because, the oldest remains imprints first and the younger fossils get deposited over and above the older ones. Advanced, complex and specialised fossils occur in the younger strata.

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