Speciation

4. Speciation that occurs when two populations of the same species get geographically isolated.
6. Natural selection that shifts the median towards one extreme
10. Theory that new species evolve through small and gradual changes taking place over long periods of time.
12. When change(s) in a species acts as the selection pressure for another species.
13. Natural selection that favours and stabilises the existing median
16. Anatomical structures that appear similar but are not inherited from a common ancestor, and have different evolutionary origins.
17. Random changes in allele frequency due to chance
18. when two populations or species start to become more and more different, but share a common ancestor.
19. Anatomical structures which have similar features and are inherited from a common ancestor.

1. Speciation that occurs when two populations of a species are in the same area and gene flow is stopped by a non-geographical barriers
2. Environmental factors that influence the likely survival of an individual
3. When rapid evolution leads to a large number of species diverging from a common ancestor.
5. When individuals with the most favourable alleles for the environment survive and reproduce, and pass their alleles on to their offspring
7. Natural selection that selects against the median and favours the two extremes
8. When an ancestral population diverges into two new species
9. Theory that species have long periods of time with no change (called stasis) followed by sudden and rapid changes.
11. A cell (or organism) with extra sets of chromosomes
14. Random, permanent changes in the base sequence of DNA
15. When two or more species which share the same environment/selection pressure evolve to become more similar to each other.