A4.1 Evolution and Speciation

Question 1

Evolution

Answer 1

cumulative change in the heritable characteristics of a population

development of life

Question 2

what have scientists now understood about evolution

Answer 2

can happen rapidly not just geologically

Question 3

theory of jean baptise Lamarck

Answer 3

physical changes occurring in a lifetime of an individual can be inherited by offspring

a blacksmiths children will inherit his muscles that he gets from working

Question 4

changes through use and disuse

Answer 4

organs that are not used aren’t passed down and the ones that are used get adapted more and more each generation

Question 5

inheritance of acquired characters lamarkism

Answer 5

an individual squires certain characteristics through their life which are then passed down to their children

Question 6

effect of environment and new needs

Answer 6

change in the environment brings about changes and gives rise to new needs

produces new structures and changes the habits of organisms

Question 7

example of acquire characteristic Lamarckism

Answer 7

giraffes neck
the giraffe wanted to reach leaves of trees to find new food so it stretched is neck
this was passed down to the next generation till the neck became very long

Question 8

Darwins theory of evolution

Answer 8

variation within a population leafs to selection pressures

they pass their adaptation to their children

Question 9

what does DNA knowledge for evolution show

Answer 9

shows that Darwin was correct by natural selection
variation caused by random mutations in DNA leading to alterations in the genetic makeup of species

Question 10

epigenetic

Answer 10

the study of heritable changes un gene activity that are not caused by changes in DNA base sequences

Question 11

what does epigenetics show

Answer 11

shows how environment factors that affect surviving of parents can alter the environment in which genes operate. changes can be inherited

Question 12

why is epigenetic evolution not stable for evolutionary change

Answer 12

only lasts for a few generations

Question 13

where does evidence for evolution come from

Answer 13

comes from many sources - study of fossils, artificial selection of domesticated breeds etc

Question 14

what is the evidence from base sequences in DNA, RNA and AA sequences

Answer 14

biochemical commonality suggests a common origin of life because there are no such differences in the major processes of life such as respiration

large molecules are susceptible to change like DNA and protiens so its possible to measure relatedness of different groups of organisms bu the amount of difference between specific molecules

Question 15

artificial selection

Answer 15

selection in breeding, carried out deliberately by humans to alter populations

Question 16

what actually happens in artificial selection

Answer 16

involves identifying the largest, best or most useful of the progeny - use them as next generation parents

Question 17

what is the outcome of artificial selection

Answer 17

continuous removal of progeny with less desired features leads to deliberate genetic change and genetic constitution of population to change fast

Question 18

example of artificial selection

Answer 18

cereal crops
wheat, barely, oats and rice - most rice and have adapted to temperate climates with moderate rains

have been modified to produce more for the growing population

Question 19

hard wheat

Answer 19

higher in protiens
grown in areas of lower rain
used to produce bread that can be kept for long

Question 20

soft wheat

Answer 20

starchier
used for making pasta and French bread
grown in humid conditions

Question 21

homologous structures

Answer 21

similar structures due to common ancestry

Question 22

natural classification

Answer 22

organisms grouped by as many common features as possible, and therefore likely to reflect evolutionary relationship

Question 23

example of evidence from homologous structures

Answer 23

limbs of vertebrates conform but show modification

they occupy similar positions in an organism, have a common underlying basic stricter but many have evolved different functions

Question 23

phylogenetic classification

Answer 23

a classification based on evolutionary relationships rather than appearances

Question 24

analogous structure

Answer 24

a feature in organisms

similar - function and superficial structure

different - fundamental structure and evolutionary origin

Question 25

artificial classification

Answer 25

classifying organisms on the basis of few, self evident features

Question 26

analogus features

Answer 26

• similar function
• different fundamental structure
• only superficial resemblances
• eg. wings of insects and birds

Question 27

homologous features

Answer 27

• similar in fundamental structure, origin and position
• can be different in function
• eg. limbs of vertebrates

Question 28

convergent evolution

Answer 28

the process by which distantly related organisms independently evolve analogous traits due to similar selection pressures

Question 29

divergent evolution

Answer 29

occurs when an ancestral species spits into two reproductively isolated groups causing each group to develop different traits due to their respective selective pressures and natural selection

Question 30

speciation

Answer 30

the process by which new species from, where one species is split into two or more species

Question 31

speciation by splitting of existing species

Answer 31

when they are separated different environmental factors would act on them causing selection process again

Question 32

why is progressive evolutionary change not speciation

Answer 32

inbreeding keeps the same gene pool

Question 33

how does barrier lead to evolution

Answer 33

separating population means they cant inbreed
overtime through natural selection adaptive genes are chosen
2 gene pools change and evolve

Question 34

roles of reproductive isolation and differential selection in speciation

Answer 34

before separation, individuals share a common gene pool, but after isolation - disturbing processes such as natural selection, mutation and random genetic differences.

Question 35

reproductive isolation

Answer 35

different species cant interbreed to produce fertile offspring

when members of related populations have evolved to this point and have become fully reproductively isolated they can have fertile offspring with members of different species

Question 36

geographical isolation

Answer 36

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

barriers can natural or man made