Lecture 4: Darwin's Evidence

Question 1

three factors necessary for natural selection

Answer 1

• variation in population
• variation leads to difference among individuals during reproductive phase
• variation must be transmitted to next generation

Question 2

exaplin evidence that organisms overbredd given available resources

Answer 2

-if given proper criteria (space, water, sunlight) populations will thrive

Question 3

Grants’ work on medium ground finch

Answer 3

• many variation in finch morphology
• post nina drought there was a great loss of tons of finches, survivors has longer and deeper beaks
• during el nino, small seeds fell out of big beaks so smaler beaks ended up dominating again

Question 4

Daphne Major

Answer 4

• island in Galapagos the Grants’ studied in after Darwin

- where large and medium ground finches lived

Question 5

can you analyze the graphs from the Grants’ work?

Answer 5

-increase or decrease in parent’s beak showed increase or decrease in offspring> correlation on coincidence

Question 6

El Nino and La Nina

Answer 6

• La Nina: drought, dry

- El Nino: flood, humid

Question 7

can you explain how the Grants’ data shows evidence of adaptation to environmental conditions?

Answer 7

-bc of the variation among the finches, they were able to adapt to different environmental condition and not allow for a species to entirely die off

Question 8

do survivors have more offspring and pass on their selected traits to the next generation?

Answer 8

• yes! the traits are heritable and are passed down to their offspring
• evolution via natural selection changed the avg beak size across generation

Question 9

why did people have have a hard time accepting Darwin’s work ?

Answer 9

-Darwin didn’t have enough evidence at his time to back up everything he said

Question 10

how does data of the age of earth support Darwin’s work?

Answer 10

-depth of canyons and thickness of strata indicated very long ad gradual natural processes

Question 11

how does data of fossil evidence of adaptation support Darwin’s work?

Answer 11

• shows extinction occurred and recent species were no longer extanct
• Darwin saw these big fossils and compared them to the modern version of them

Question 12

how does data of the percent of living fossils decreasing the older rock strata support Darwin’s work?

Answer 12

-bc he has evidence of animals being alive from up to ~50 MYA

Question 13

how does data on the Archaeopteryx support Darwin’s work?

Answer 13

• has aspects of both bird and reptile that can be clearly seen in fossils
• its a transitional form

Question 14

how does data on modern examples of transitional forms support Darwin’s work?

Answer 14

• the # of transitions we have now shows us that species change overtime and species do adapt to changing environments (proof of evolution)
• supports natural selection

Question 15

the problem with missing links

Answer 15

-can’t ever eliminate missing links

Question 16

ambulocetus natans

Answer 16

• an evolved four legged mammal but can swim

- transitioned from a whale (thus its a transitional form)

Question 17

tiktaalik

Answer 17

-a transitional form btwn fish and amphibbian

Question 18

equidae

Answer 18

-transition to horse-like animal

Question 19

hyracotherium

Answer 19

• believed to be first horse

- size was small to medium sized dog