module 4 - 10.8 changing populations characteristics

Question 1

what is evolution by natural selection?

Answer 1

• variation in traits
• differential reproduction
• heredity
• evolution

Question 2

what is variation in traits?

Answer 2

• variety of phenotype and genotype of individuals
• you have to assume this is genetic variation for natural selection to happen

Question 3

what is differential reproduction?

Answer 3

• not all individuals get to reproduce to their full potential
• selection pressure - selects those individuals that can reproduce

Question 4

what is heredity?

Answer 4

e.g. surviving brown beetles have brown baby beetles because this trait has a genetic basis

Question 5

what is evolution?

Answer 5

• usually over many generations
• the more advantageous trait allows individual to have more offspring and becomes more common in the population
• eventually all individuals in the population will have advantageous trait

Question 6

what is a niche?

Answer 6

the role of an organisms habitat, reproduction, disease etc.

Question 7

what are the 14 concepts in natural selection?

Answer 7

1. there is a fit between organisms and their environments
2. evolution results from selection acting upon genetic variation within a population
3. new heritable traits can result from recombination of existing genes or genetic mutations in reproductive cells
4. mutations are random
5. advantageous traits are adaptations
6. inherited characteristics affect survival and reproduction
7. inherited characteristics can be advantageous, neutral or detrimental
8. random factors affect survival
9. natural selection acts on variation
10. organisms can’t intentionally produce adaptive mutations in response to environmental influences
11. populations evolve not individuals
12. proportion of individuals with advantageous adaptations increases over time
13. evolution results in genetic drift acting on genetic variation
14. fitness is reproductive success

Question 8

what is methicillin-resistant staphylococcus aureus (MRSA)?

Answer 8

• groups of gram-positive bacteria that are genetically distinct from other strains of staphylococcus aureus
• responsible for several hard-to-treat infections in humans
• MRSA is any strain of S. aureus that’s developed through natural selection or acquired through horizontal gene transfer

Question 9

what is the evolution of the peppered moth an example of?

Answer 9

directional evolution by natural selection

Question 10

how is the evolution of the peppered moth an example of directional evolution by natural selection?

Answer 10

• frequency of dark coloured moths increased at that time
• dark moths become the dominant form compared to peppered moths
• this selective survival was due to birds which easily cause dark moths on clean trees, and white moths on trees darkened with soot

Question 11

what is the founder effect?

Answer 11

loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population
(extreme version of genetic drift)