phylogeny Flashcards
What is phylogeny? (1)
The study of the evolutionary history of groups of organisms
What does a phylogenetic tree represent? (2)
It demonstrates how all organisms
Have evolved from shared common ancestors
According to phylogenetics, what defines a species? (1)
A species is the smallest group that shares a common ancestor
How does phylogeny relate to classification systems? (2)
Classification systems now take phylogeny into account when arranging organisms into groups
System = cladistics
What were Darwin’s four key observations that led to his theory of evolution? (4)
Organisms produce more offspring than survive
There is variation in the characteristics of members of the same species
Some characteristics can be passed on from one generation to the next
Individuals best adapted to their environment are more likely to survive.
What is the basic premise of Darwin’s theory of evolution by natural selection? (2)
Individuals with advantageous adaptations are more likely to survive, reproduce, and pass on their traits
Leading to evolution over time
What is a selection pressure? (2)
Environmental factors that affect an organism’s chances of survival
Such as predation, disease, or competition
How do genes contribute to evolution according to modern understanding? (3)
Genes determine many of an organism’s characteristics
Advantageous alleles can be passed on to offspring
Leading to evolution over generations
How does the fossil record provide evidence for evolution? (3)
By arranging fossils in chronological order
Gradual changes in organisms can be observed
Showing the process of evolution over time
How does DNA provide evidence for evolution? (2)
Evolution causes gradual changes in an organism’s DNA
Organisms that diverged more recently have more similar DNA sequences
