biology unit 2

what are some examples of hazards in the field

difficult terrain, isolation, adverse weather conditions, harmful organisms

ways to reduce risk in the field

appropriate equipment, clothing footwear and means of communication

how should sampling of wild organisms be carried out?

be carried out in a way that minimises the impact on wild species and habitats

when sampling what species should extra consideration be given to?

rare and vulnerable species and habitats that are protected by legislation

what is a point count and what is it used for?

records all individuals seen from a fixed point, is often used for birds

what is a quadrat and what is it used for?

a frame of know area used to count plants or sessile/slow moving animals

what is a transect?

straight line across a large area, measurements are taken at regular intervals along it

what are examples of capture techniques and what do you use them for?

traps and nets, are used for mobile species

what is indirect sampling?

does not require seeing the organism is used for illusive speices eg. scat sampling

what are camera traps used for?

a direct method for sampling elusive species

what are some ways of identifing organisms?

classification guides, biological keys, analysis of DNA or proteins

what is taxomany?

classification of organisms based on shared characteristics, uses morphology

what is phylogenetics?

the study of evolutionary history and relationships, uses inheritable traits such as morphology, DNA sequences, protein structure

what is phylogentics changing?

the traditional classification of many organisms

examples of taxonomic groups

nematodes, arthropods, chordates

what are model organisms?

organisms that are easily studied or well studies

what does the study of model organsims allow for?

application of information onto species in the same taxonomic group that cannot be ass easily studied

examples of model organims

E-coli (bacteria), arabidopsis thaliana (flowering plant), C.elegans (nemitode), Drosophila melangaster (arthropod), mice, rates and zebra fish (chordates)

what is an indicator species?

a species who’s presence absence or abundance can give information on environmental quality

what is susceptible spieces?

absence or reduced population in response to environmental factor

what is a favoured species?

abundance or increased population in response to environmental factor

what is mark and recapture?

technique used to estimate population size

what is the mark and recapture equation?

number= number caught in 1st capture x number caught in second capture / number recaptured

what does mark and recapture assume?

all individuals have an equal chance of being caught, there is no emigration or immigration, marked individuals can mix fully and randomly with the population

what are some methods of marking?

banding, tagging, surgical implantation, painting, hair clipping

method of marking and observation in mark and recapture should…

minimise the impact on the study species

what is latency?

time between a stimulus occurring and a response behaviour

what is frequency?

number of times a behaviour occurs within an observation period

what is duration?

length of time each behaviour occurs for

what is an ethogram?

list of species specific behaviour that can be used to record during observation

what is a time budget?

the proportion of time an animal spends in different behaviours, can be calculated from data collected during observation

what is anthropomorphism and its effect on results?

the attribution of human traits emotions or intentions to animals, it should be avoided as it leads to invalid conclusions

what is an arthropod?

invertebrates with segmented bodies and paired appendages

what are classed as chrodates

vertebrates and sea squirts

what is convergent evolution?

when distantly related species evolve similar characteristics independntly

what is divergent evolurion?

what closely related species evolve and accumulate differences

what is an elusive species?

species that is difficult to see because of its habitat behaviour or rarity

what is a nematode

a round worm, they have unsegmented thread like bodies

what is remote detection?

the ability to show an animals presence from a distance eg. using camera trap or scat sampling

what is evolution?

the change overtime in the proportion of individuals in population differing in one or more inherited traits

why does evolution occur?

changes in allele frequency caused by natural selection, sexual selection and genetic drift

what does natural selection act on?

genetic variation within a population

what is natural selction?

the non-random increase in the frequency of advantageous alleles and decrease in disadvantageous alleles

how does variation occur?

through mutation which is the source of new DNA sequences

when does natural selection occur?

when populations produce more offspring than an enviroment can support

what are advantageous alleles

alleles that increase the likelihood of an individual surviving and reproducing

what is sexual selction?

a non-random process that involve the selection of alleles that increase an individuals chances of mating and producing offspring

what can sexual selection lead to?

sexual dimorphism

what is sexual dimorphism?

when different sexes of the same species exhibit different physical characteristics

what is advantageous in male-male rivalry male male rivalry?

large size and/or weaponry

what is advantageous in female choice?

elaborate markings and displays

what is genetic drift?

a random process where a chance event causes unpredictable fluctuations in allele frequency from one generation to the next

what populations does genetic drift have a greater impact on?

smaller populations as alleles are more likely to be lost

how does genetic drift effect allele frequencies?

it can cause over or under representation of certain alleles

what is the founder effect?

when a few members of a population are isolated, gene pool may not be representative of the original population

what is the bottleneck effect?

when population size is reduced for at least one generation, it can lead to lower genetic diversity

what are selection pressures?

environmental factors that influence which individuals in a population pass on their alleles

what happens when selection pressures are strong?

the rate of evolution is more rapid

what is the hardy-Weinberg priciple?

in the absence of evolutionary influences allele and genotype frequencies in a population will remain constant over generations

what is required to maintain the hardy Weinberg equilibrium?

no natural selection, random mating, no mutations, large population size, no gene flow

what can the hardy wienburg principle be used for?

to determine if allele frequencies are changing, this would suggest evolution

what is the HW equation for genotype?

p²+2pq+q²

what is the equation for allele frequency?

p+q=1

how would you find the frequency of the ressesive allele?

q=square root of recessive individuals/total population

what is fitness?

an indication of an individuals success in surviving and reproducing, it shows the tendency of some organisms to produce more surviving offspring than competing members of the same species.

what does higher fitness mean?

an individual is more likely to survive and reproduce

what is the fitness of a genotype?

the contribution of a genotype to the gene pool of the next generation

what does more offspring indicate

higher fitness

what is absolute fitness?

the ratio of individuals of a genotype before and after selection (between generations)

how would you calculate absolute fitness?

frequency after selection/frequency before selection

what does an absolute fitness of 1 indicate?

genotype is stable

what does an absolute fitness of less than 1 indicate?

genotype is decreasing in frequency

what does an absolute fitness of more than 1 indicate?

a genotype is increasing in frequnecy

what is relative fitness?

the ratio of surviving offspring from a genotype to the surviving offspring of the most successful genotype

how would you calculate relative fitness?

surving offspring of genotype/surviving offspring of most successful genotype

what is the relative fitness of the most successful genotyope?

1

what is coevoltion?

process by which two or more species evolve in response to selection pressures imposed by each other

what does the change in traits of one species act as in a co-evolutionary relationship?

a selection pressure

in what intreactions is co-evolution frequently seen in?

symbiotic interactions

what is symbiosis?

a co-evolved intimate relationship between 2 different species

what impact can symbiosis have on the species involved?

positive (+) negative (-) neutral (0)

what is mutalism?

symbiotic relationship where both species benefit and are interdependent on each others resources/services +/+

what is commensalism?

symbiotic relationship where one spiecs benefits and the other is unaffected +/0

what is parasitism?

symbiotic relationship where one species benefits by the gain of energy/nutrients and the other is harmed by their loss +/-

what is the red queen hypothesis?

in a co-evolutionary relationship the change in traits of one species acts as a selection pressure on the other

what does the red queen hypothesis mean?

species in co-evolutionary relationships must evolve to avoid extinction

female choice

mechanism of sexual selection where females assess fitness of males and choose a mate