lecture 10 - natural selection

Question 1

natural systems

Answer 1

most species produce excess offspring
most real populations are stable not increasing
there is limited food
no 2 individuals look the same
traits are heritable young resemble their parents

Question 2

conclusions from natural systems

Answer 2

less than 100% of young survive because of competition, being eaten by predators, disease
only individuals who do best in the environment grow up
individuals inherit traits that fit their current environment and are more likely to pass on good traits

Question 3

how does differential survival change allele frequency

Answer 3

eventually 1 allele will reach fixation and one will become extinct

Question 4

what did Mendel discover that solved darwins problem

Answer 4

natural selection is the change in frequency of stable variants

Question 5

does breeding remove variation

Answer 5

no, but natural selection does - can happen very quickly

Question 6

3 ways evolution was thought to progress on the geological timescale

Answer 6

gradualism
punctuated equilibrium
punctuated gradualism

Question 7

punctuated gradualism

Answer 7

evolution is gradual but varies in both rate and direction

Question 8

variation leads to 3 types of selection over a geological timescale

Answer 8

directional selection- move towards 1 extreme
stabilizing selection - mean of the population is best
disruptive selection - one extreme or the other no imbetween

Question 9

how does inclusive fitness have an effect on gene propagation

Answer 9

directly in the bodies of offspring
indirectly via non-descendent kin

Question 10

what is the measure of fitness

Answer 10

number of offspring produced and offspring of all other relatives and how many go on to breed

Question 11

what measurement is used instead of fitness

Answer 11

partial fitness

Question 12

why do organisms act to maximise their fitness

Answer 12

they have to
by fighting for mating opportunities
by having lots of offspring
by looking after their own interests

Question 13

2 important perspectives when thinking about evolution

Answer 13

its not about individual its a race between genes
animals are in competition with others of their species

Question 14

4 widely misunderstood natural selection concepts

Answer 14

only selects within the variation in the population
cannot plan ahead- only respond to the current environment
between individuals but evolution happens to populations
there is no intent or purpose to evolution it just happens