Evolution

BELLWORK What was the most difficult part of designing and conducting your own experiment? Write one paragraph - you will turn this in for a grade.

EVOLUTION The term evolution does not refer to the idea that man and ape may have had a common ancestor. evolution - a change in genetic characteristics from one generation to the next

Survival of the Fittest “Fit” individuals are more likely to survive than “unfit” ones. Why is this important? Because they pass their characteristics on to future generations!

What does “fit” mean? Fit organisms are more adapted to their environment. adaptation - a genetic trait that increases an organism’s chance of survival in a specific environment

Natural Selection natural selection - allows individuals that are better adapted to their environment to survive and pass on their genes to future generations examples: -giraffes with longer necks can reach trees easier -wolves with thicker fur survive in cold environments -chameleons catch prey by blending in with surroundings

Which is Natural Selection? TPS 1) A leopard builds strong muscles in his legs by climbing trees every day, so climbing becomes easier for him the more he does it. 2) Over time, cheetahs become extremely fast in order to be able to catch fast prey such as gazelles or jackrabbits.

ANSWER #2 is natural selection because faster cheetahs were more likely to survive and pass on their genetic speed to their cubs. #1 is not natural selection because the leopard’s strength is not a genetic trait that is passed down to its offspring.

Which is Natural Selection? TPS 1) Over time, butterflies develop bright marking on their wings that can frighten predators and give them a chance to escape. 2) Over time, many different breeds of domestic (pet) dogs evolve from one common ancestor: the wolf.

ANSWER #1 is natural selection because colorful butterflies are more likely to survive and pass on colorful genes to their offspring. #2 is not natural selection because the dogs did not adapt to their natural environment. They were intentionally bred by humans.

Artificial Selection artificial selection - the selective breeding of organisms by humans for specific characteristics examples: dogs: bred to be friendly and loyal to humans crops: bred to be bigger or taste better cows: bred to produce a lot of milk or meat