4B Genetic Diversity

Question 1

What is genetic diversity?

Answer 1

the number of different alleles in a species or population

Question 2

What is a phenotype?

Answer 2

A displayed characteristic

Question 3

Why is genetic diversity important?

Answer 3

• it is important in maintaining the ecological fitness of a population
• if a population has low genetic diversity it may not be able to adapt to a change in the environment

Question 4

How could genetic diversity be increased within a population?

Answer 4

• mutations can produce new alleles which may be advantageous and increase likelihood of survival
• new alleles may be brought in via migration, they may interbreed with the current population and bring different alleles in (referred to as gene flow)

Question 5

What are genetic bottlenecks?

Answer 5

• these cause the size of a population to dramatically reduce
• may be due to a new disease or a new predator or increased hunting

Question 6

What do genetic bottlenecks cause?

Answer 6

• when the size of the population decreases, the gene pool gets smaller (no. of alleles)
• surviving members reproduce and new population is based on the genetic diversity of a few individuals so new population has much lower genetic diversity than original

Question 7

Describe the Founder effect

Answer 7

• a few members of a population may leave and relocate to start a new colony
• an allele that may have been rare in the original pop may be very common in the new one
• this results in a general reduction in genetic diversity
• may occur due to migration or if the new population becomes isolated from the original

Question 8

Describe the Amish population

Answer 8

• in American east
• case study of founder effect
• entire population is descended from a small group of 17th century Swiss settlers
• they have remained genetically isolated for much of their history and as such show very little genetic variety

Question 9

Describe the Ellis-van Creveld syndrome

Answer 9

• traced back to Samuel King and his wife
• came to Amish area in 1744
• mutated gene causing the syndrome was passed alonng from King and his offspring
• today the syndrome is many times more common in Amish than the American population at large

Question 10

What is selective breeding?

Answer 10

• aka artificial selection
• select individuals to breed based on desirable characteristics

Question 11

Describe natural selection

Answer 11

• over generations, the frequency of beneficial alleles will increase
• this is because beneficial ones increase the survivability of organisms so they are more likely to reproduce and pass on the allele

Question 12

List the stages of natural selection

Answer 12

1. there is different levels of reproductive success, individuals with beneficial alleles are more likely to survive and reproduce
2. there is a greater frequency of this allele in the next generation, these are more likely to have reproductive success than those without the allele
3. over several generations the allele becomes much more common in the population, population becomes better adapted to living in a particular habitat which leads to evolution

Question 13

What are the 3 types of adaptations?

Answer 13

• behavioural, acts eg. penguin huddling
• physiological, processes eg. bears hibernating
• anatomical, phyical features eg. whales have blubber

Question 14

What is directional selection?

Answer 14

• the range remains relatively constant
• the mean frequency increases

Question 15

What is stabilising selection?

Answer 15

• the range decreases
• the mean frequency becomes more concentrated

Question 16

What is disruptive selection?

Answer 16

• the frequency is most at the middle but then splits to be high and low and uncommon in the middle

Question 17

What is phylogeny?

Answer 17

• the study of the evolutionary development of organisms
• it looks at how closely related different species are

Question 18

What is a LUCA?

Answer 18

• last universal common ancestor
• all organisms on earth share a luca
• every species has evolved from this organism

Question 19

What is taxonomy?

Answer 19

• the branch of science related to the classification of organisms
• involves naming organisms and assigning them to various taxonomic groups
• the phylogeny of an organism is considered when undergoing classification

Question 20

How many taxons are there and list them in order

Answer 20

• there are 8 taxons
  Domain
  Kingdom
  Phylum
  Class
  Order
  Family
  Genus
  Species

Question 21

How many domains are there? List them

Answer 21

3
archaea
bacteria
eukarya

Question 22

How many kingdoms are there? List them

Answer 22

5
Animal
Plant
Fungi
Protist
Monera

Question 23

Describe the taxonomy hierarchy system

Answer 23

• as you move down the system, each group becomes more closely related
• there is only ever 1 type of organism per species

Question 24

Define species

Answer 24

• a species is a group of similar organisms that can reproduce to yield fertile offspring
• this is the biological species concept

Question 25

Describe the binomial system

Answer 25

• a scientific standard for naming organisms
• Carl Linnaeus created the system
• in Latin
• consists of the genus starting with a capital letter followed by the species with a lowercase letter
• often in italics
• names organisms in a standardised way
• avoids confusion and language barriers

Question 26

What is courtship behaviour?

Answer 26

• helps an organism to attract mates
• specific to each species
• helps to prevent interbreeding as only certain species respond to certain rituals

Question 27

Describe morphology

Answer 27

• how organisms look
• traditional methods of classification were based on this

Question 28

What modern methods are there that can be used to help classify organisms?

Answer 28

• comparing genomes, similar species will have a high degree of similarity in their DNA sequences
• the protein cytochrome c oxidase is found in a variety of eukaryotic and prokaryotic life and can be compared to aid classification

Question 29

Describe how immunology can be used during classification

Answer 29

• the proteins in closely related organisms will bind to the same antibodies so scientists can design antibodies that are complementary to a particular protein
• any protein that is structurally similar to the original will also bind to the antibody eg. humans and chimpanzees create similar proteins

Question 30

Describe the method as to how proteins created by different organisms can be compared

Answer 30

1. human serum (blood plasma) is injected into a rabbit
2. an immune response is triggered in the rabbit
3. the serum is extracted and human serum is added to it to form a precipitate
4. the rabbit serum is added to serum extracted from different animals
5. the quantities of precipitate formed can be compared