4B Genetic Diversity Flashcards
1
Q
What is genetic diversity?
A
the number of different alleles in a species or population
2
Q
What is a phenotype?
A
A displayed characteristic
3
Q
Why is genetic diversity important?
A
- 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
4
Q
How could genetic diversity be increased within a population?
A
- 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)
5
Q
What are genetic bottlenecks?
A
- these cause the size of a population to dramatically reduce
- may be due to a new disease or a new predator or increased hunting
6
Q
What do genetic bottlenecks cause?
A
- 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
7
Q
Describe the Founder effect
A
- 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
8
Q
Describe the Amish population
A
- 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
9
Q
Describe the Ellis-van Creveld syndrome
A
- 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
10
Q
What is selective breeding?
A
- aka artificial selection
- select individuals to breed based on desirable characteristics
11
Q
Describe natural selection
A
- 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
12
Q
List the stages of natural selection
A
- there is different levels of reproductive success, individuals with beneficial alleles are more likely to survive and reproduce
- 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
- 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
13
Q
What are the 3 types of adaptations?
A
- behavioural, acts eg. penguin huddling
- physiological, processes eg. bears hibernating
- anatomical, phyical features eg. whales have blubber
14
Q
What is directional selection?
A
- the range remains relatively constant
- the mean frequency increases
15
Q
What is stabilising selection?
A
- the range decreases
- the mean frequency becomes more concentrated
16
Q
What is disruptive selection?
A
- the frequency is most at the middle but then splits to be high and low and uncommon in the middle
17
Q
What is phylogeny?
A
- the study of the evolutionary development of organisms
- it looks at how closely related different species are
18
Q
What is a LUCA?
A
- last universal common ancestor
- all organisms on earth share a luca
- every species has evolved from this organism
19
Q
What is taxonomy?
A
- 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
20
Q
How many taxons are there and list them in order
A
- there are 8 taxons
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
21
Q
How many domains are there? List them
A
3
archaea
bacteria
eukarya
22
Q
How many kingdoms are there? List them
A
5
Animal
Plant
Fungi
Protist
Monera
23
Q
Describe the taxonomy hierarchy system
A
- as you move down the system, each group becomes more closely related
- there is only ever 1 type of organism per species
24
Q
Define species
A
- a species is a group of similar organisms that can reproduce to yield fertile offspring
- this is the biological species concept
25
Q
Describe the binomial system
A
- 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
26
Q
What is courtship behaviour?
A
- helps an organism to attract mates
- specific to each species
- helps to prevent interbreeding as only certain species respond to certain rituals
27
Q
Describe morphology
A
- how organisms look
- traditional methods of classification were based on this
28
Q
What modern methods are there that can be used to help classify organisms?
A
- 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
29
Q
Describe how immunology can be used during classification
A
- 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
30
Q
Describe the method as to how proteins created by different organisms can be compared
A
- human serum (blood plasma) is injected into a rabbit
- an immune response is triggered in the rabbit
- the serum is extracted and human serum is added to it to form a precipitate
- the rabbit serum is added to serum extracted from different animals
- the quantities of precipitate formed can be compared
