Evolution 1 & Evolution 2

Question 1

Define evolution

Answer 1

genetic change in a population over generations

Question 2

difference between small and large scale evolution

Answer 2

small occurs from one generation to the next

large is descent of diff. species from com. ancestor over many gens

Question 3

What are the three levels of debate and their meaning

Answer 3

1. fact- do pops change over time?
2. course- what course did it take?
3. mechanism- what causes evolutionary change?

Question 4

Carolus Linneaus theorised what? explain

Answer 4

Fact: Fixity of species

- no evolution, created as seen today

Question 5

What are the three levels debated by Lamarck

Answer 5

Fact: change of species
Course: scale naturae
Mech: inheritance of acquired characteristcs

Question 6

Explain Lamarcks inheritence of acquired characteristics

Answer 6

o Environment change > developing new needs to meet new demands
Needs altered animals’ metabolism to change physiology + new traits passed onto offspring

Question 7

What did Sir Charles Lyell describe? and explain

Answer 7

• Principal of Uniformitarianism
  o Laws of physics and chemistry not changed
  o Same geological events of pasts seen today

Question 8

Darwins first three observations?

Answer 8

1. able to reproduce > enables growth of pop.
2. pops stay same size
3. nat. resources are limited

Question 9

what inference did the first three observations of darwin create

Answer 9

Inference 1: struggle for existence

Question 10

Darwins 4 and 5th observation

Answer 10

4. variation occurs

5. variation is inheritable

Question 11

what did inference 1, observations 4 and 5 produce of darwin

Answer 11

inference 3: organisms show differential survival + reproduction, favouring advantageous traits = nat selec

Question 12

explain inference 3 of darwin

Answer 12

nat selection, acting over many gens, produces new adaptions and new species

Question 13

explain the mechanism natural selection

Answer 13

♣ Individuals w/ more favourable traits would fare better than competitors > survive + pass on traits

Question 14

what are the three things evolution by natural selection requires

Answer 14

1. variation
2. differential reproduction
3. heredity

Question 15

what are the three levels of debate theorised by darwin

Answer 15

• Fact: Populations of a species changes over time
• Course: descent with modification
• Mechanism: Natural selection

Question 16

what were three challenges faced by darwin

Answer 16

1. Competing theories
2. Time (current theory did not fit estimated timeline of Earth)
3. Inheritance (unknown exact course of inheritance)

Question 17

why does blending inheritence not go with darwins theory

Answer 17

if black flower was advantageous= lose trait

Question 18

define population

Answer 18

a group within a species of interbreeding individuals and their offspring in the same geographic location

Question 19

define gene pool

Answer 19

all genes in the eggs and sperm in a population

Question 20

does natural selection act on the pheno or genotype

Answer 20

pheno

Question 21

how do new traits arise?

Answer 21

mutation

Question 22

define mutation

Answer 22

♣ spontaneous error in DNA replication leading to a heritable change in an individual’s genome
♣ Not a ‘change in genetic code’

Question 23

what two things determine fitness

Answer 23

survival + reproductive success

Question 24

define adaption

Answer 24

anatomical structure, physiological process, or behavioural trait that evolved by natural selection and improves a organisms ability to survive and leave descendants

Question 25

two types of selection pressures

Answer 25

♣ Biotic factors (related to another organism- own or another species i.e. competition)
♣ Abiotic factors (relate to environment i.e. topography)

Question 26

what are the 3 types of selection

Answer 26

natural selection, articifial, sexual

Question 27

what are the three types of natural selection

Answer 27

a. Stabilising selection: selects against extreme phenotypes (loses extremes, = more narrow, mean remain same)
b. Directional selection: phenotypic character shifts in one direction (pushes range as selects against one phenotype)
c. Disruption selection: selects against average phenotypes (average of range= lower fitness than extremes- bimodal distribution= can result in two species)

Question 28

define sexual selection

Answer 28

• Selection of trait that give individual an advantage in attracting mates (even if harmful to survival), increase reproductive success

Question 29

what are the types of sexual selection

Answer 29

♣ Intresexual: ‘Power to conquer:’ outcompeting other males

♣ Intersexual: ‘Power to charm:’ competing to attract female

Question 30

how can a trait decrease survival chances

Answer 30

trait uses up energy/ visibility to predators

Question 31

explain when fitness enables a trait to decrease survival chances

Answer 31

o Fitness consists of survival + fertility. If the in fertility (through the ability to attract multiple mates) outweighs the in survival, then fitness overall is

Question 32

4 steps of speciation

Answer 32

1. variation
2. isolation
3. selection
4. speciation

Question 33

define gradualism

Answer 33

Large differences in anatomical traits that characterise species originate through accumulation of many small incremental changes over long periods of time

Question 34

define punctuated equilibrium

Answer 34

Long periods of evolutionary stasis (no change) followed by relatively short periods of rapid evolutionary change