A4.1 Evolution and Speciation

Question 1

evolution

Answer 1

the development of life
the process of cumulative changes in the heritable characteristics of a population

Question 2

lamarck’s theory of evolution

Answer 2

change through use and disuse
inheritance of acquired characteristics
effect of environment and new needs

Question 3

how does darwin contrast with lamarck

Answer 3

proposed that variation within a population leads to selection pressures enabling organisms that are better adapted to the enviornment to survive and pass on this advantage to future generations

Question 4

what do modern genetics show in terms of evolution

Answer 4

acquired biological characteristics cannot be inherited unless they cause a change to the organisms DNA

Question 5

what do epigenetics show

Answer 5

how environmental factors that affect parents can alter the environments in which genes operate and that these cahnges can be inherited by offspring, leading to alteration of gene expression in the next gen
they do not lead to long term changes, only last a few gen

Question 6

evidence of evolution from base sequences in DNA/RNA

Answer 6

reading code, protein synthesis, respiration etc are all common suggesting a common origin for life as the biochemical differences between living things of today are limited

Question 7

evidence for evolution from selective breeding of domesticated animals and crop plants

Answer 7

gneeration of variation on which artificial selection acts is no different from the generation of variation in natural population

Question 8

evidence of evolution from homologous structures

Answer 8

many organisms seem to have a common underlying base strucutre, such as limbs that then diverge to form based on specific needs

Question 9

analogous structures

Answer 9

organisms that have similar functions but fundamentally different origins

Question 10

artificial classification

Answer 10

classification based on analogous structures

Question 11

convergent evolution

Answer 11

when different species evolve similar biological adaptations in response to similar selective pressures
happens when there are similar ecological niches

Question 12

divergent evolution

Answer 12

when evolution comes from a common ancestor

Question 13

speciation

Answer 13

a process in which ancestral species are separated causing different environmental factors to act on them, forming new species

Question 14

how can separation in speciation occur

Answer 14

throuhg the formation of barrier, causing the sme gene pool to evolve differently

Question 15

how can new species appear

Answer 15

through speciation

Question 16

reproductive isolation

Answer 16

when different species cannot interbreed and have fertile offspring meaning gene flow between them is prevented. This means they are of different species

Question 17

geographical isolation

Answer 17

occurs when barriers arise and restrict the movement of individuals between the divided populations

Question 18

example of geographic isolation

Answer 18

seen in two species of apes that theoreticlly got separated million of years ago by the congo river

Question 19

temporal isolation

Answer 19

when organisms produce gametes at different times or seasons when they are active at different times of the day

Question 20

behavioural isolation

Answer 20

when organisms acquire distinctive behaviour routines, not matched indiviuals of the same species

Question 21

allopatric speciation

Answer 21

isolating mechanisms that involve spatial separation
physically separated

Question 22

sympatric speciation

Answer 22

isolating mechanisms that occur within the same location, such as temporal/behavioural isolation

Question 23

adaptive radiation as a source of biodiversity

Answer 23

concept is seen in the similarity of limbs in vertebrates as evidence for evolution
leads to many diverse species
different roles or niches provide a range of different selection pressures which lead to variety of species

Question 24

polyploidy

Answer 24

an abrupt change in the structure of number of chromosomes may lead to a new species

Question 25

which organisms are usually polyploids

Answer 25

largely restricted to plants and thought to be its most important evolutionary process

Question 26

the two mechanisms with which polyploids form

Answer 26

a diploid gamete fuses with a haploid one, creating triploid offspring
diploid with diploid gamete, resulting in tetraploid offspring

Question 27

polyploid orgnaisms can be divided into two categories

Answer 27

autopolyploid - result of diploid genome
allopolyploid - result of distinctive genomes combining

Question 28

polyploidization can explain what

Answer 28

the speed of invasive plant evolution, allowing them to spread and establish
why invasive species are more likely to be polyploid

Question 29

what do hybrid organisms usually show

Answer 29

improved bio function compared to parents and are usually larger, more fertile and invasive