sci_bio

Evolution & Natural Selection

Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.

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Biology · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)

Some finches have thicker beaks, some thinner. This variation is the raw material selection acts on; without it, nothing can be selected.

The environment cannot support everyone. This competition is the 'selection pressure' that decides who lives long enough to breed.

A thick-beaked finch on a seed island eats well and raises more chicks. 'Fittest' means best-suited, not strongest.

Repeat for thousands of generations and one ancestor can give rise to new, well-adapted species, like Darwin's finches.

evolution	the gradual change in inherited characteristics of a species over many generations
natural selection	the process by which better-suited individuals survive and pass on their traits
variation	the differences in characteristics between individuals of the same species
mutation	a random change in DNA that creates new variation
adaptation	an inherited feature that helps an organism survive in its environment
homologous structures	body parts with the same basic plan but different uses, showing common ancestry
speciation	the formation of a new species, often after a population is isolated
artificial selection	humans breeding organisms for chosen traits; also called selective breeding

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