Mechanisms of evolution Flashcards
what are the 3 key factors of evolution?
Hereditary, variation, Differential reproduction
Which is example of evolution?
Beetles are smaller because not enough food.
The color of beetles change throughout generations
The color change, a small body size is not determined by genetics,
In the second one you compare 2 gens and they are different
What are the mechs of change
MIgration, mutation, Genetic drift, natural selection,
What is migration
ex . some new members join a population. This adds some more variation to the population.
ex. could cause parents with
genes for bright green colouration to
have offspring with gene for brown
colouration.
Mutation
What is genetic drift
Selection is caused by a random event.
one example is a bunch of green beetles get stepped on, this will cause fewer green beetles in the next gen.
What is natural selection example
Some beetles that are green are easier to see and therefore are eaten. The brown ones that are not eaten get to reproduce. The next gen will have more brown beetles.
What are sources of genetic variation
Mutations, gene flow,sex, and genetic shuffling
What are mutations in terms of genetic variation
They are random, they can be beneficial, harmful, or neutral
They do not always matter to evolution (if its in somatic cells)
what are the causes of mutation
DNA fails to copy accurately
Radiation - it destroys DNA which repairs itself but not perfectly
What is gene flow
It is the same as migration
any movement of genes from on pop to another
can be a source genetic variation
What is sex and genetic shuffling
When the genes are mixed through mating
It introduces new gene variations to population
Effects of genetic drift on evolution
Reduces genetic variation, acts faster and has more drastic results, contributes to speciation
What is a population bottleneck
When the population size is reduced for at least one generation.
reduces genetic variation in small gens
pop will not adapt that quick
What is the founder effect
When small numbr breaks off from bigger pop and starts a new pop.
this causes smaller genetic variation in the new pop
also non random sample of genes
What does natural selection need to have
hereditary - traits need to be genetic
differential reproduction - not everyone can reproduce
Variation in traits
What is fitness
used to describe how good a genotype is at producing offspring
example that help fitness
caring for offspring, having fancy feathers to attract mate ,
What is sexual selection
Sexual selection acts on an
organism’s ability to mate.
What animals will do to find a mate, sometimes making it harder to survive,
ex peacocks
What is female choice
females can choose which males to mate with, and sometimes whos sperm can fertilize egg.
What is male competition
males compete to access female
What are the ways we can get things at are not through adaption
Its a result of history - it always has been
Its a by product - ex blood is red because of the chemistry of blood
outdated adaption - might have been an adaption for past environment
Genetic drift - it is random, some traits are kept at random
What is an example of a bottleneck in evolution
northern elephant seals have low gen variation because bottleneck caused by humans in 1890
what are some examples of natural selection at work
katydids look like leaves, king snake mimic poisonous coral snake
What are some misconceptions about natural selection.
Natural selection does not make perfect being, just good enough.
its a process not a guiding hand
