3- natural selection

Question 1

natural selection

Answer 1

the process where individuals better adapted to their environment due to advantageous traits are more likely to survive, reproduce and pass on beneficial alleles to offspring

Question 2

evolution

Answer 2

the change in allele frequencies in a gene pool over time, primarily due to natural selection

Question 3

ways evolution happens:

Answer 3

• variation in phenotypes
• environmental changes and selection pressure
• advantageous alleles
• passing on of advantageous alleles
• change in allele frequency

Question 4

how evolution happens- variation in phenotypes

Answer 4

mutations introduce a variety of phenotypes within a population, contributing to genetic diversity

Question 5

how evolution happens- environmntal changes and selection pressures

Answer 5

changes in the environment alter the selection pressure, influencing the survival and reproduction of individuals based on their traits

Question 6

how evolution happens- advantageous alleles

Answer 6

individuals possessing advantageous alleles have a selective advantage, enabling them to survive and reproduce more effectively

Question 7

how evolution happens- passing on of advantageous alleles

Answer 7

these advantageous alleles are transmitted to the next generation, promoting the traits that provide a selection advantage

Question 8

how evolution happens- change in allele frequency

Answer 8

over time, natural selection leads to a change in the frequency of alleles in a population, driving evolution

Question 9

niche occupation in organisms

Answer 9

organisms occupy niches based on physiological, behavioural and anatomical adaptations.

Question 10

niche of a species

Answer 10

its role within its community

Question 11

species competition and survival

Answer 11

species sharing the same niche compete, with the better adapted species surviving. this principle forms the foundation of natural selection

Question 12

types of adaptations in organisms

Answer 12

• physiological
• behavioural
• anatomical

Question 13

physiological adaptations

Answer 13

biochemical processes inside an organisms body that increase chances of survival

Question 14

examples of physiological adaptations

Answer 14

• hibernating bears lower their metabolic rate so no food is needed during winter
• extremophiles near hydrothermal vents contain heat-stable enzymes and proteins

Question 15

behavioural adaptations

Answer 15

aspects of an organisms behaviour that aid survival

Question 16

examples of behavioural adaptations

Answer 16

• lizards bask in the sun to warm up in the morning and burrow if it gets too hot
• bird migration

Question 17

anatomical adaptions

Answer 17

structural features of an organism which increase chances of survival

Question 18

anatomical adaptations examples

Answer 18

• brightly coloured petals attract pollinators
• bacterial flagella aid in movement
• blubber in certain marine mammals provide insulation

Question 19

reproductive isolation

Answer 19

• the inability to breed successfully and produce fertile offspring due to various barriers
• helps maintain the genetic integrity by preventing or reducing gene flow

Question 20

types of reproductive isolation

Answer 20

• biochemical isolation
• behavioural isolation
• anatomical isolation
• temporal isolation
• spatial isolation
• barriers to fertilisation
• formation of sterile hybrids

Question 21

biochemical isolation

Answer 21

a biochemical change prevents fertilisation

Question 22

behavioural isolation

Answer 22

a courtship dance or behaviour is not recognised or attractive to mates

Question 23

anatomical isolation

Answer 23

differences in sexual organs can prevent successful mating

Question 24

temporal isolation

Answer 24

different flowering or mating seasons

Question 25

spatial isolation

Answer 25

different parts of the habitat are occupied, and they are less likely to meet

Question 26

barriers to fertilisation

Answer 26

changes to the uterus or stigma can prevent gametes from meeting

Question 27

formation of sterile hybrids

Answer 27

in mules, pairs of homologous chromosomes do not form in meiosis, preventing the production of viable gametes

Question 28

speciation

Answer 28

reproductive isolation between two populations can lead to the formation of new species due to the accumulation of different genetic information over time

Question 29

where does allopatric speciation occur

Answer 29

due to geographical isolation

Question 30

allopatric speciation

Answer 30

1) a physical barrier (like a flood, volcanic eruption or earthquake) isolated some individuals from the main population 2) environmental conditions may vary on each side of the barrier, leading to different selection pressures 3) different characteristics will be selected for/against on different sides, changing allele frequencies due to varying advantageous traits 4) mutations occur independently in each population, altering allele and phenotype frequencies further 5) over time, the populations become unable to interbreed and are reproductively isolated, forming separate species

Question 31

sympatric speciation

Answer 31

- occurs without geographical isolation - factors such as temporal, behavioural or gametic isolation come into play

Question 32

examples of sympatric speciation

Answer 32

the giant iguana lizards on the galápagos islands, with one species terrestrial and the other adapted to marine life

Question 33

evolutionary race between pathogens and medicines

Answer 33

- an evolutionary competition exists between bacteria and the development of medicines - this is because bacteria evolve antibiotic resistance that enable them to survive and reproduce

Question 34

development of antibiotic resistance- mutations

Answer 34

random mutations create strains that are less susceptible or even immune to certain antibiotics. antibiotics eliminate non resistant bacteria, but resistant strains can survive

Question 35

development of antibiotic resistance- survival and reproduction of resistant bacteria

Answer 35

the elimination of non resistant bacteria reduces competition for resources, allowing resistant bacteria to thrive. these bacteria reproduce and pass on their resistant alleles to their offspring

Question 36

development of antibiotic resistance- formation of resistant populations

Answer 36

over time, and with continued exposure to antibiotics, a completely resistant bacterial population can form