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
Describe the binomial system
- 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
What is courtship behaviour?
- helps an organism to attract mates
- specific to each species
- helps to prevent interbreeding as only certain species respond to certain rituals
27
Describe morphology
- how organisms look
- traditional methods of classification were based on this
28
What modern methods are there that can be used to help classify organisms?
- 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
Describe how immunology can be used during classification
- 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
Describe the method as to how proteins created by different organisms can be compared
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
