organisms and evolution Flashcards
definition of a hazard
something with potential to cause harm
definition of a risk
the likelihood of harm arising from exposure to a hazard
what does risk assessing involve?
identifying control measures to minimise risk
how should sampling wild organisms be carried out?
- in a way that minimises the impact on wild species and habitats
- consideration should be given to rare and vulnerable species and habitats that are protected by legislation
4 different sampling techniques
- point count
- transect line
- remote detection
- capture techniques
capture techniques
- traps and nets
- used for mobile species like mice
remote detection
- used to detect elusive species
- camera traps/scat sampling
point count
- involves recording all individuals seen from a fixed location
- can be compared to other locations or same location at a different time
transect line using quadrats
- line along which different samples can be taken, set up along an area with variable terrain or abiotic factors
- allows sessile organism abundance to be recorded
- abiotic features can also be measured to determine habitat features of organisms
two ways in which organisms can be classified
taxonomy and phylogenetics
what is taxonomy?
identification and naming of organisms and classifying them based on shared characteristics
- based on morphology
what is phylogenetics?
the study of evolutionary history and relationships among individuals or groups of organisms
- uses heritable traits to make inferences about an organisms evolutionary history
what is a phylogenetic tree?
a diagrammatic hypothesis of an organism’s relatedness to other organisms
what does genetic evidence reveal?
relatedness obscured by divergent or convergent evolution
three taxonomic groups needed
nematodes: round worms which show great variety, often parasitic
arthropods: joint-legged invertebrates which are identified by their segmented body, typically paired with appendages (wasps, spiders, butterflies)
chordates: sea squirts and vertebrates (birds, reptiles, amphibians, fish)
what are model organisms?
organisms which have been well studied or are easily studied
- used to obtain information that can be applied other species which are more difficult to study directly
methods of monitoring populations
- banding
- tagging
- surgical implantation
- painting
- hair clipping
indicator species
presence, absence/abundance of them can give info of environmental qualities such as the presence of pollutants
what does an absence of indicator species suggest?
a species is susceptible to some factor in the environment
what does an abundance of indicator species suggest?
a species is favoured by the conditions
what is ethology?
the study of animal behaviour
ways of quantifying animal behaviour?
latency, frequency, duration
what is latency?
time between stimulus occurring and the response behaviour
what is frequency?
number of times a behaviour occurs within the observation period
what is duration?
the length of time each behaviour occurs for during the observation period
what is an ethogram?
a method of recording animal behaviours over a set period of time
what is recorded in an ethogram?
- specific behaviours observed and recorded
- duration of each behaviour and total time of observation are recorded
- time budget can be constructed to show the percentage of time spent on each behaviour
what is anthropomorphism?
assigning human emotions to animal behaviour
why should anthropomorphism be avoided when performing an ethogram?
it can lead to invalid conclusions
what is evolution?
the change over time in the proportion of individuals in a population differing in one or more inherited trait
2 ways changes in allele frequency can occur
selection (natural or sexual)
genetic drift
what is natural selection and how does it arise?
- non-random increase in frequency of advantageous alleles and non-random decrease in frequency of deleterious alleles
- acts on genetic variation
- arises as a result of mutation
what will happen when more offspring are produced than the environment can handle?
only the best adapted will survive
what is sexual selection?
non-random process involving the selection of alleles that increase the chance of mating and producing offspring
- doesn’t increase chances of survival
what is sexual selection due to?
either male to male rivalry or female choice
what is male to male rivalry
- males compete aggressively to defend territories and gain access to females
what is female choice?
females will choose a male based on traits he displays, if males cannot control access to females
what is genetic drift?
random process which results in an increase or decrease in the frequency of inherited traits
when does genetic drift occur?
when a chance event such as a natural disaster causes unpredictable fluctuations in allele frequency from one generation to the next
examples of genetic drift
- population bottlenecks
- founder effects (isolation of a few members of a population from a larger one - gene pool is therefore not representative of the original pool)
what are selection pressures?
environmental factors that influence which individuals in a population pass on their alleles
- can be biotic or abiotic
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 is fitness in evolution?
a measure of the tendency of some organisms to produce more surviving offspring than competing members of the same species
two ways in which fitness can be defined
absolute or relative terms
definition of absolute fitness
ratio between the number of individuals of a particular genotype after selection, to that before selection
definition of relative fitness
ratio of number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype.
what is co-evolution?
the process by which two or more species evolve in response to selection pressures imposed by each other
where is co-evolution seen?
in pairs of species that have symbiotic relationships
what is symbiosis? + 3 types
co-evolved intimate relationship between members of two different species
- mutualism, commensalism, parasitism
sexual reproduction definition
offspring arise from the combination of male and female gametes after the process of fertilisation
asexual reproduction
offspring arise from a single organism and share the DNA of that parent only