1.2 Evolution Flashcards
IB Definition
Evolution is the process of cumulative change in the heritage characteristics of population over time
Evidence for Evolution
Fossils
Homologous Structures
How do fossils show evolution?
- Show change in evolution over time
- Show transitional forms between ancestral and modern species
- Show extinct species (change has occurred)
- Show homologous structures
Homologous Structures
- Structure inherited from a common ancestor
- Develop through adaptive radiation
- Similar structure but may have evolved different functions (pterodactyl limb)
Adaptive Radiation
- Usually rapid diversification from a common ancestor
- Adaptive radiation of vertebrates led to the pterodactyl limb evolving new functions from the same structure
- The diversification of a group of organisms into forms filling different ecological niches
Artifical Selection
Process in which humans consciously select for or against particular features in organisms
Continous Variation
Variation along a range, such as height or color
Divergent Evolution
Common ancestor, become more different over time
Convergent Evolution
No common ancestor, structure become more similar (analogous structures - Fins on orcas vs. Fins of Sharks)
Descent
Inherited from an ancestor
Niche
The role a species has in its environment to meet its needs for survival and reproduction
Tetrapod
Animals that have four legs and 5 toes on each foot
Extinction
The process of species dying out
Phenotype
Individual characteristics resulting from interaction of genotypes with the environment
What are fossils?
The remains of plants or animals that have been embedded and preserved in rocks
