3.4.4-Genetic Diversity And Adaptation Flashcards
(20 cards)
What is genetic diversity?
The number of different alleles of genes in a population
Natural selection can only occur if…
There is genetic diversity within a population
What is natural selection?
The process that leads to evolution in populations
How can adaptations be characterised?
Anatomical
physiological
Behavioural
What is an anatomical adaptation?
Structural/physical features which inverse chance of survival
What is a physiological adaptation?
Processes/chemical reactions inside an organisms body that increase chance of survival
What is a behavioural adaptation?
Ways an organism acts that increases chance of survival
Natural selection results in…
Species better adapted to their environment
Process of natural selection
-Random mutations result in new alleles of a gene
-If the new alleles increases the chances of the individual to survive in that environment they’re more likely to survive and reproduce
-The advantageous allele is inherited by members of the next generation
-As a result over many generations the new allele increases in frequency
What are the two types of selection?
Directional selection
Stabilising selection
What is directional selection?
When one of the extremes has the selective advantage as a response to a change in the environment
Eg.antibiotic resistance in bacteria
What is stabilising selection?
Organisms with a modal trait has the selective advantage in an unchanging environment
Eg.babies with an average weight
What 4 things can be compared to assess genetic diversity?
1.observable characteristics
2.DNA base sequence
3.mRNA base sequence
4.amino acid sequence
Other than hunting, suggest two reasons why populations might show very low levels of genetic diversity
Population might have been very small
Inbreeding
The spotted owl is a bird. The number of spotted owls have decreased over the past 50 years explain how this decreased may affect genetic diversity.
Reduce genetic diversity as there is a reduced gene pool
Aseptic techniques that could be used in bacteria practical
Wash hands with soap/disinfect surfaces
Flame neck of bottle of bacteria
Work close to Bunsen burner as upward current of air draws airborne microbes away
Lift lid of Petri dish slightly and away from mouth to prevent microbe entry
Describe a method to investigate the effect of antimicrobial substances on microbial growth
Prepare area using as septic techniques (name)
Use a sterile pipette to transfer bacteria to agar plate using a septic techniques (name)
Use a sterile spreader to evenly spread bacteria over agar plate
Place same size discs soaked in different types/concentrations of antimicrobials for same length of time onto agar plate
Lightly tape lid onto plate and incubate at 25°C for 48 hours
Measure diameter inhibition zone around each disk and calculate area using pi r squared
Why is the lid not sealed completely on the agar plate?
Allows oxygen to prevent the growth of anaerobic bacteria which is more likely to be harmful to humans
Why is a paper disk with water or no antimicrobial agent used?
To act as a control ensuring antimicrobial prevented growth, not the paper disc
Why should bacteria be incubated at 25°C or less in a school environment?
Below human body temperature to prevent the growth of harmful pathogens
