Speciation

What is a species?

• A group of organisms that can mate with each other and produce fertile offspring. 
• A group of organisms that genetically are very different from each other. 
• A group of organisms that can mate and produce offspring even if those offspring are infertile.
• Indivual organisms that live in the same environment. 

If two species form a hybrid that is not viable it is what kind of reproductive barrier?

• Prezygotic
• Postzygotic
• Allopatric
• Sympatric

Fruit flies are beginning to live & mate on different types of fruit on the floor of the Amazon. Bigger fruit flies prefer rotting mangos, while smaller fruit flies prefer rotting bananas. What type of reproductive barrier is this?

• habitat isolation
• temporal isolation 
• gametic isolation
• mechanical isolation 

The pollen (sperm) of a flowering plant cannot fertilize the egg cell of a nearby flowering plant of its kind. What type of reproductive barrier is this?

• behavioral isolation
• temporal isolation 
• gametic isolation
• geographic isolation 

The genitalia of the male damselfly varies in shape. Certain males can only hold onto & mate with females whose genitalia fit.  What type of reproductive barrier is this?

• behavioral isolation
• temporal isolation 
• gametic isolation
• mechanical isolation 

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When a zebra & horse mate, they create a zorse. Zorses are most often sterile. What type of reproductive barrier is this?

• behavioral isolation
• hybrid sterility 
• gametic isolation
• mechanical isolation 

The flowers of pink tulips open in the morning, while the flowers of lavender tulips open in the early afternoon. The bees that pollinate these tulips cannot carry pollen back & forth between the two types of tulips because of their flowers being closed at different times of day. What type of reproductive barrier is this?

• behavioral isolation
• hybrid sterility 
• temporal isolation
• mechanical isolation 

What evidence does speciation provide for the theory of evolution by natural selection?

• Speciation can show us that new species don't choose to adapt, but have changed due to diverging from an original species due to reproductive barriers.
• Speciation can show us that new biological species can come from divergence (separating) due to reproductive barriers.
• Speciation can show us that environmental changes & genetic variation play a role in the process of a new species diverging from an original species due to reproductive barriers. 
• All of the above fit!

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What is founder effect?

• Any change in the allelic frequencies in a population that is due to chance
• ›A small sample of a population settles in a location separated from the rest of the population
•   The process in which humans select for or against particular features in organisms
• ›Members of one sex choose mates with particular features

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What is genetic drift?

• The movement of genes in/out of a population
• A small, random change in the DNA
• Any change in the allelic frequencies in a population that is due to chance
• ›The process in which humans select for or against particular features in organisms