Amoeba Sisters Speciation

Which of the following best defines a “species” as described in the video?

• Any two organisms that look similar

• A group of organisms that can interbreed and produce viable, fertile offspring

• Any organisms that live in the same habitat

• A population of organisms that share the exact same DNA

What is a characteristic of organisms within the same species?

• They cannot interbreed.

• Their offspring are always sterile.

• They can interbreed and have fertile offspring.

• They are always identical in appearance.

What is a Zonkey?

• A new species of dog

• A type of bird

• A type of cat

• A hybrid of a donkey and a zebra

What is allopatric speciation?

• Speciation due to behavioral differences

• Speciation in the same habitat

• Speciation due to geographic barriers

• Speciation without any barriers

Which of the following is a prezygotic barrier?

• Hybrid sterility

• Behavioral isolation

• Genetic drift

• Natural selection

What is the role of isolation in speciation?

• It prevents any form of evolution.

• It ensures all species look the same.

• It separates gene pools for other mechanisms to act.

• It is the mechanism for change over time.

Suppose a beetle population is split when a glacier recedes, creating a lake dividing the land. After thousands of years, the two populations can’t interbreed even though they look alike. This is best classified as which type of speciation and why?

• Sympatric speciation, because they diverged in the same region

• Allopatric speciation, because geographic separation occurred

• Hybrid speciation, because they still look alike

• Artificial speciation, because the glacier forced the change

Two fish species in the same lake evolve: one breeds in spring and the other in fall, so they never mate although they live together. Over time they accumulate genetic differences and cannot interbreed. Which barrier is at work, and why might speciation occur in this case?

• Habitat isolation; because they live in different zones of the lake

• Temporal isolation; because they breed at different times

• Postzygotic barrier; because their offspring would be sterile

• Behavioral isolation; because they swim differently