Why Evolution is True and Early Evo Bio Flashcards
(19 cards)
What is EVOLUTION?
Evolution is the change in the frequency of alleles in a population over time
What is the concept of Common Descent?
The relatedness among all organisms
Homologous trait
Similar trait among different species because of inheritance from a common ancestor
Variation in form and function among species can be attributed to 3 reasons:
mutation, genetic drift, natural selection
Why evolution is true (1)
- A ____ explanation for both ____and ____
single; similarities; variations
Why evolution is true (2)
No other explanation is as ___ (the most popular alternative is infinitely ____)
simple; complex
Why evolution is true (3)
No other ____ has been supported by the ____ ____
Hypothesis; scientific method
Hypothesis
Untested ideas based on observations; usually NARROW in scope
Theories
Explanations that incorporate facts, laws, inferences, and/or other hypotheses; usually BIG in scope.
Facts
Observations that have been repeatedly confirmed and are accepted as “true”
Laws
Descriptive generalizations about nature
*Usually logical or rigid in some way.
Phylogenetic tree
Diagram of evolutionary relationships among a group of organisms
What does the root on a phylogenetic tree represent?
The ancestor of all species in the tree
What does the nodes on a phylogenetic tree represent?
The ancestor of the species that belong to a single clade
What is a clade?
The species that share a common ancestor (tips that share a single node)
2 different representation of the branches on a phylogenetic tree
Scaled / unscaled
Scaled branches
Branches will be different lengths based on the number of evolutionary changes or distance – May convey additional info such as mutations and the time at which the branches start to diverge
Unscaled branches
All branches in the tree are the same length – only considers evolutionary relationships between species
Branch length can represent ____ or the rate of ____ change.
Time; genetic
