evolution theory

Question 1

what is evolution?

Answer 1

• The process in which significant changes in the inheritable traits (genetic makeup) of a species occur over time
• biological change over time
• sequence of events depicting the gradual progression of changes in the genetic composition of a biological population over successive generations

Question 2

how has the earth changed over time?

Answer 2

• human actions: changes to the amazon rainforest over 70 years
• without human interaction: extinction of the dinosaurs

Question 3

what causes evolution?

Answer 3

• mutations

- artificial selection

Question 4

mutations

Answer 4

• permanent random change in the genetic material of an organism
• caused by errors in DNA copying of cells that are exposed to mutagens (radiation)
• mutations can be good, bad or neutral (most are neutral, some can be harmful, if it occurs in gametes it can be passed onto offspring, some give increased reproductive success)
• ie harmful: 2 faced cats, helpful: camouflage

Question 5

artificial selection

Answer 5

• directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation
• used to produce new breeds or varieties of plants and animals
• occurs in captivity and not a natural setting
• ie. Canis lupis (earliest animal to be domesticated was the wolf, all modern breeds of dogs are descended from wolves, dogs are considered a sub species and give the scientific name canis lupus familiaris)
• thousands of years of artificial selection have produced a great variety of dog breeds

Question 6

limitations to artificial selection

Answer 6

• not all attempts to artificial selection have been successful
• breeders cannot create traits that do not already exist in some form within the population
• an example is blue roses no amount of crossbreeding will create a true blue rose
• breeders must work with the genetic diversity that already exists in the population

Question 7

does evolution really matter?

Answer 7

• darwin’s theory
• fish are shrinking in size- traits for smaller body size is passed down because small fish are always tossed back and larger fish are removed to be eaten
• where did HIV come from- chimps in 1900
• why are grasslands turning into deserts- plants depend on wild grazers to move soil around, fertilize it with their feces and urine and remove excess vegetation
• theory of evolution is guiding us to new discoveries

Question 8

why harmful mutations do not accumulate over time?

Answer 8

-it is selected against and does not accumulate over time because it reduces the reproductive success of an individual

Question 9

how is possible for mutations to play such a key role in evolution?

Answer 9

mutations create new genetic info and add genetic diversity to species