Evolution Flashcards
How do you read a tree?
Nodes - common ancestor.
Branches - lines that represent evolutionary relationships and passage of time
Topology - the overall shape of how species diverge from common ancestor
What is asymmetrical speciation and give examples of successful novelties?
Rapid diversification producing many descendant species, while other doesn´t.
Novelties:
- Jaws in vertebrates
- Wings in insects
What are the three geological eras?
- Cambrian explosion 500 m.y.a
- Extinction of dinosaurs 65 m.y.a
- Divergence of human and chimpanzee 10 m.y.a.
What is a cladogram and a phylogenetic tree?
A cladogram is a diagram that shows the relationship between species based on shared characteristics. A phylogenetic tree also shows the same, but also evolutionary time and the amount of change.
What are the differences between a monophyletic group and a paraphyletic group?
A monophyletic group includes an ancestor and all of its descendants. A paraphyletic group includes a common ancestor and some, but not all, of its descendants.
Mechanism of evolution
Random change and natural selection
What is random change?
Genetic variation within a population. This variation happen through random changes such as:
Mutation, genetic drift and cross-over
What is natural selection?
The process in which certain traits become more or less common in a population due to their impact on the survival and reproduction. Non-random
What is the difference between divergent and convergent evolution?
Divergent: common ancestor that leads to different traits.
Convergent: no common ancestor that leads to similar traits
At what level does evolution happen?
The gene.
What is the difference between orthologs and paralogs?
Orthologs are genes in different species that evolves from a common ancestral gene. Paralogs evolve new functions, even though they originate from the same ancestral gene.
