Patterns of Evolution n n n Divergent evolution

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Patterns of Evolution: n n n Divergent evolution – the accumulation of differences between

Patterns of Evolution: n n n Divergent evolution – the accumulation of differences between related groups Convergent evolution – the accumulation of similarities between unrelated groups Coevolution – the process by which 2 or more species evolve in response to changes in each other.

Divergent vs. Convergent Similar Characteristics

Divergent vs. Convergent Similar Characteristics

Coevolution

Coevolution

Are the following pairs examples of divergence or convergence: ___ C 1. ___ D

Are the following pairs examples of divergence or convergence: ___ C 1. ___ D 2. Platypus Duck (mammal) (bird) Both lay eggs C 4. ___ D 3. Venomous Snake Both Mammals Lives in Water Lives on Land Nonvenomous Snake Shark Dolphin (fish) (mammal) Both streamlined

SPECIATION: n n species – a group of organisms that are closely related and

SPECIATION: n n species – a group of organisms that are closely related and can naturally mate to produce fertile offspring speciation – the formation of new species as a result of evolution by natural selection; occurs when a species becomes so different they can no longer interbreed and are eventually considered to be different species

What leads to speciation (the formation of a new species)?

What leads to speciation (the formation of a new species)?

Reproductive Isolation leads to Speciation. v Reproductive Isolation – is the condition in which

Reproductive Isolation leads to Speciation. v Reproductive Isolation – is the condition in which two populations of the same species can no longer breed with one another Ex: as two isolated populations of the same species become more different over time, they may eventually become unable to breed with one another; generally, when the individuals of two related populations can no longer breed with one another, the two populations are considered to be different species.

Factors that lead to Reproductive Isolation: n n n Geographical isolation – physical barriers

Factors that lead to Reproductive Isolation: n n n Geographical isolation – physical barriers such as rivers or mountains separate a population Temporal Isolation – timing prevents reproduction between a population Behavioral Isolation – differences on courtship or mating behaviors

Identify which type of reproductive isolation is being described below: →Geographical isolation →Temporal Isolation

Identify which type of reproductive isolation is being described below: →Geographical isolation →Temporal Isolation →Behavioral Isolation T 1. The Red-legged Frog breeding season lasts from ___ January to March. The closely related Yellow-legged Frog breeds from late March through May. ___ G 2. A mountain range prevents two types of goat from mating, causing the gene pool to become less varied. B 3. Female fireflies only flash back and attract males ___ who first signaled to them with a species-specific rhythm of light signals. G 4. A forest fire causes the permanent separation of a ___ group of deer from their native population, causing the small group to interbreed only with one another.