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7 Cards in this Set
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(What leads to speciation ?) Explain how 2 different species could have developed from an ancestral species. [6] |
Isolation by geographical barrier/sea ↓ Variation in isolated population(different alleles caused by mutation) ↓ Different environmental conditions EG. Climate/predators/food ↓ Natural selection on the isolated population (Only certain favorable(different) alleles passed on to offspring) ↓ So difference lead to inability to interbreed |
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What do fossil provide evidence that species today have evolved from simpler organism?[3] |
1) fossils are organism that lived a long time ago. 2)fossils show changes overtime 3) fossils have similar features as present- day species. species.
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Why are scientists unsure about the theory of evolution [2] |
1) lack of valid/reliable evidence 2)Because the early organisms were soft bodies and soft tissues decay. 3) remains destroyed by geological action |
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Definition of fossils |
Fossils are the dead remains of plants and animals (organisms) from many years ago. |
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Why are there gaps in the fossil records? |
-Many early organisms were soft bodied, and the soft tissues decay away completely, so fossil record is incomplete. -destroyed by geological activity. eg. Movement of tectonic plates. |
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Why have some species become extinct? |
1) environment changes too quickly.(EG. Destruction of habitat) 2) a new predator 3) a new disease 4) competition for food 5) a catastrophic event EG. Volcanic eruption or collision with an asteriod 6) a new specie develop |
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Definition of evolution |
Organism that can breed together successfully to produce a fertile offspring |
