Field Techniques for Biologists / evolution Flashcards
what are hazards in fieldwork
adverse weather conditions
difficult terrain
problems associated with isolation
contact with harmful organisms
what is risk
the likelihood of harm arising from exposure to a hazard
what is a risk assessment
involves identifying control measures to minimise risk
what are some control measures
appropriate equipment, clothing, and footwear
means of communication
what does a point count involve
the observer recording all individuals seems from a fixed point count location
this can be compared to other point count locations or with data from the same location gathered at other times
what are capture techniques for mobile species
traps and nets
how do you sample elusive species
directly - camera traps
indirectly - scat sampling
how can you identify an organism
classification guides
biological keys
analysis of DNA or protein
what is taxonomy
the identification and naming of organisms and their classification into groups based on shared characteristics
classic taxonomy is based on morphology
what is phylogenetics
- the study of the evolutionary history and relationships among individuals or groups of organisms
- uses heritable traits such as morphology, DNA sequences, and protein structure to make inferences about an organism’s evolutionary history and create a phylogeny (or phylogenetic tree) - a diagrammatic hypothesis of its relationships to other organisms. genetic evidence can reveal relatedness obscured by divergent or convergent evolution
give examples of taxonomic groups
nematodes, arthropods, and chordates
what are model organisms and give examples
model organisms are those that are either easily studied or have been studied well
- the bacterium - E. coli
- the flowing plant - Arabidopsis thaliana
- the nematode - C. elegans
- the arthropod - Drosophila melanogaster
- the chordate - mice, rats, and zebrafish
equation for estimating a population size
N= MC / R
what are methods of marking animals
banding
tagging
surgical implantation
painting
hair clipping
what are measurements used to quantify animal behaviour
latency - the time between the stimulus occurring and the response behaviour
frequency - the number of times a behaviour occurs within the observation period
duration - the length of time each behaviour occurs during the observation period
what is animal behaviour recorded on
an ethogram
why should you avoid anthropomorphism when analysing behaviour
it can lead to invalid conclusions
what is evolution
the change over time in the proportion of individuals in a population different in one or more inherited traits
what causes changes in allele frequency
non-random - natural selection, sexual selection
random - genetic drift
describe natural selection
- natural selection acts on genetic variation
- variation in traits arises as a result of mutation
- mutation is the original source of new sequences of DNA
- these new sequences can be novel alleles
- most mutations are harmful or neutral, but in rare cases they may be beneficial to the fitness of an individual
describe selection
- individuals with variations that are better suited to their environment tend to survive longer and produce more offspring, breeding to pass on those alleles that conferred an advantage to the next generation
- selection results in the non-random increase in the frequency of advantageous alleles and the non-random decrease of deleterious alleles
describe sexual selection
- the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring
- sexual selection can lead to sexual dimorphism
- sexual selection can be due to male-male rivalry and female choice
describe male-male rivalry
large size or weaponry increases access to females through conflict
describe female choice
females assessing the fitness of males
describe genetic drift
- occurs when chance events cause unpredictable fluctuations in allele frequencies from one generation to the next
- important in small populations, as alleles are more likely to be lost from the gene pool
- a gene pool is altered by genetic drift because certain alleles may be under-represented or over-represented and allele frequencies change
describe the bottleneck effect
population bottlenecks occur when a population size is reduced for at least one generation
how does selection pressure influence the rate of evolution
where selection pressures are strong the rate of evolution can be rapid
what are selection pressures and give examples
selection pressures are the environmental factors that influence which individuals in a population pass on their alleles
examples
biotic - competition, predation, disease, parasitism
abiotic - changes in temperature, light humidity, pH, salinity
what does the hardy-weinberg principle state
in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over the generations
what are the condition for painting the HW equilibrium
- no natural selection
- random mating
- no mutation
- large population size
- no gene flow (migration etc)
what is the HW equation and what does each symbol mean
p^2 +2pq+q^2 =1
p = frequency of dominant allele
q = frequency of recessive allele
p^2 = frequency of homozygous domination genotype
q^2 = frequency of heterozygous genotype
2pq = frequency of heterozygous genotype
what is fitness and what does it measure
fitness is an indication of an individual’s ability to be successful at surviving and reproducing
fitness is a measure of the tendency of some organisms to produce more surviving offspring than competing members of the same species
what is absolute fitness and how is it calculated
- the ratio between frequency of individuals of a particular genotype after selection, to those before selection
frequency of a particular genotype after selection / frequency of a particular genotype before selection
what does the absolute fitness show
=1 frequency of that genotype is stable
>1 increase in the genotype
<1 decrease in the genotype
what is relative fitness and how is it calculated
the ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype
number of surviving offspring per individual of a particular genotype /
number of surviving offspring per individual of the most successful genotype
explain co-evolution
- the process by which two or more species evolve in response to selection pressures imposed by each other
- a change in the traits of one species acts as a selection pressure on the other species
- co-evolution is frequently seen in pairs of species that have symbiotic interaction
explain symbiosis
co-evolved intimate relationships between members of two different species
the impacts of these relationships can be positive (+), negative (-) or neutral (0) for the individuals involved
what is mutualism
both organisms in the interaction are interdependent on each other for resources or other services
as both organisms gain from the relationship, the interaction is (+/+)
what is commensalism
only one of the organisms benefit but he other is unaffected (+/0)
what is parasitism
the parasite benefits in terms of energy or nutrients and the host is harmed as the result of the loss of these resources (+/-)
what does the red queen hypothesis state
in a co-evolutionary relationship, change in the traits of one species can act as a selection pressure on the other species
this means that species in these relationships must adapt to avoid extinction
