| Front | What are homologous structures? |
| Back | They have different mature forms but all starts from the same embryonic tissueStructural similarities show evidence of common ancestor. Over many generations the bodyparts adapt to environment as they slowly change - Forelimbs of animals |
| Front | Darwin's idea |
| Back | Girafe were all born with different lengths of neck, those with short necks won't reach as much leaves meaning they die faster. Natural selection leaves those with long necks and over time, only the longest necks remain and reproduce. |
| Front | What are variatoins |
| Back | differences among individuals(inheritable variation) - Among species(no two alike)Sources of variations:- Random mutations**ultmate source***- Genetic recombinations during meiosis(crossing over)- Migrations(gene flow) |