1. Populations Evolve

Question 1

Why is Darwin famous?

Answer 1

provided a plausible mechanism for evolution → natural selection

Question 2

What is natural selection?

Answer 2

the differential reproductive success of individuals within a population
- causes evolution → changes in the genetic composition of a population over time

Question 3

Why are cats usually different colours?

Answer 3

individuals can vary within populations

Question 4

What is Darwins theory?

Answer 4

• organisms within species vary in traits
• some variation is due to genes
• populations have the capacity to over-reproduce

Question 5

What inferences did Darwin make in his theory?

Answer 5

Inference 1: some survive to reproduce, some don’t
Inference 2: those with higher reproductive success leave more offspring and copies of their genes

Question 6

What is a Darwinian theory to why giraffe’s necks are so long?

Answer 6

those with longer necks have more access to vegetation
sexual selection (long necks, yum!)

Question 7

What do populations evolve in response to? Example?

Answer 7

environmental change, fish living above vs. below a waterfall

Question 8

What is the definition of evolution?

Answer 8

change in gene frequency within a population (not possible in a single organism)

Question 9

What is the unit of evolution?

Answer 9

population is the unit of evolution, not the species
- much of the biodiversity on earth is at the within species level
sometimes differences between populations are trivial, but other times they’re very important

Question 10

What is an example of proof to the unit of evolution?

Answer 10

the same species of ibex mated, but they were from different regions with different birthing patterns, chaos ensues

Question 11

What is important about “populations evolve”?

Answer 11

• be careful when stocking or moving organisms
  
  • specifically across landscapes → see case study
  • the wrong species can destroy local adaptation
• local populations usually outperform “foreign” populations (the ones added in)

Question 12

What is a case study proving that different populations of the same species should be kept apart?

Answer 12

• escapees from fish farms can interbreed and threaten wild stocks
  
  • “Atlantic salmon” → many of the east coast Atlantic salmon is endangered
  • wild fish are swamped/outnumbered by escapees

Question 13

What is COSEWIC?

Answer 13

committee on the status of endangered wildlife in Canada
(any species, subspecies or variety or genetically distinct population?)

Question 14

What is the species at risk act?

Answer 14

Genetically discrete and significant populations get protection under the species at risk act (SARA)