Concepts 1.1-1.3 (Evolution) Flashcards
What is evolution?
The cumulative change in the genetic composition of a population or species over time
What are Darwin’s 3 major propositions?
- Species are not immutable
- Descent without modification
- Natural selection
What is meant by species are not immutable?
Populations show phenotypic variation and species can change overtime
What is meant by descent without modification?
Related species, which share a common ancestor, diverge from one another gradually overtime
What is meant by natural selection?
Differences in the phenotypes of individuals cause some of them to survive and reproduce more effectively than others and therefore outcompete them
What is speciation?
An evolutionary consequence of reproductive isolation
What do phylogenies describe?
The degree of similarity in the genetic info and common ancestry of organisms
What does macroevolution explain?
The evolutionary changes among large taxonomic groups above the species level
How can phylogenies be produced?
Using DNA or protein sequences, and morphology
What is a polyphyletic group?
Does not include the common ancestor
What is a monophyletic group?
Includes the common ancestor and all descendants (a “clade”)
What is an adaptation?
A favoured trait that spreads through a population by natural selection
What is involved in convergent evolution?
Similar traits in different species not due to common descent. They evolved independently for similar purposes
