Unit 2 Flashcards
Examples of hazards and what should be done about them
uneven/ challenging terrain, weather
conditions and isolation, should be identified and risk assessed
how should sampling be carried out and what should be given consideration?
in a manner that minimises impact on the wild species and habitats, consideration given to rare and vulnerable species and habitats
techniques for sampling wild organisms
transects (a line along which different samples are taken), point counts (counts of organisms seen and heard from a stationary point), remote detection (camera traps), quadrats, camera traps and scat sampling (indirect)
how can chosen techniques be appropriate for species being sampled?
-quadrats of suitable size and shape are used for sessile and slow-moving organisms
- capture techniques for mobile species
- elusive species can be sampled directly using
camera traps or indirectly using scat sampling
how can a sample be identified?
classification guides, biological keys or
analysis of DNA or protein
what does familiarity with taxonomic groupings allow?
predictions and inferences to be made between the biology of an organism and better-known (model) organisms
what does genetic evidence reveal?
relatedness obscured by divergent or convergent evolution
three domains
archaea, bacteria, eukaryota
plant kingdom main divisions
mosses, liverworts, ferns, flowering plants, conifers
phyla of the animal kingdom
Chordata, Nematoda, Arthropoda, Mollusca, Platyhelminthes
chordata
sea squirts and vertebrates
Arthropoda
joint-legged invertebrates: segmented body
typically with paired appendages
Nematoda
round worms: very diverse, many parasitic
Platyhelminthes
flatworms: bilateral symmetry, internal organs but no body cavity, many parasitic
Mollusca
molluscs: diverse, many with shells
what are model organisms from within all taxonomic groups used for?
to obtain information that can be applied to species that are more difficult to study directly
Model organism that have been important in the advancement of modern biology
- bacterium- E.coli
- flowering plant- Arabidopsis thaliana
- nematode- C. elegans
- arthropod- Drosophila melanogaster
- chordates- mice, rats and zebrafish
indicator species
presence, absence or abundance can give information about enviromental qualities such as presence of pollutant
Mark and recapture
method for estimating population size
A sample of the population is captured and marked (M) and released. After an interval of time, a second sample is captured (C). If some of the individuals in this second sample are recaptures (R) then the total population N = (MC)/R, assuming that all individuals have an equal chance of capture and that there is no immigration or emigration.
methods of marking
banding, tagging, surgical implantation, painting and hair clipping
method of marking and tagging must
minimise the impact on the study species
ethogram
recording of all observed behaviors shown by a species over a period of time
what does an ethogram of the behaviours shown by a species in a wild context allow?
construction of time budgets- shows % of time spent on certain activities
measurements taken for ethogram
latency (time taken for animal to respond to a particular stimulus), frequency and duration of certain behaviours and activites
anthromorphism
when animals are credited with human emotions and qualities, must be avoided
evolution
change over time in the proportion of individuals in a population differing in one or more inherited traits
how can evolution occur?
random processes of genetic drift or non-random processes of natural and sexual selection
genetic drift
random change in how frequently a particular allele occurs within a population
why is genetic drift is more important in small populations?
alleles are more likely to be lost from the gene pool
natural selection and sexual selection cause
certain alleles to occur more frequently within a population because they confer a selective advantage
mutation
causes variation in traits to arise, original source of novel sequences of DNA, most are harmful but rarely can be beneficial to fitness of an individual
absolute fitness
ratio of frequencies of a particular genotype from one
generation to the next
F1/P
relative fitness
ratio of surviving offspring of one genotype compared
with other genotypes
absolute fitness of one genotype/ absolute fitness of most successful genotype
As organisms produce more offspring than the environment can support
those individuals with variations that best fit their environment are the ones most likely to survive and breed. Through inheritance, these favoured traits are therefore likely to become more frequent in subsequent generations
selection pressures
environmental factors that may reduce the reproductive success in a population and thus contribute to evolutionary change or extinction
where selection pressures are high
rate of evolution can be rapid
rate of evolution can be increased by
shorter generation times, warmer environments, the sharing of beneficial DNA sequences between different lineages through sexual reproduction and horizontal gene transfer
coevolution is frequently seen between
pairs of species that demonstrate a symbiotic relationship- interact frequently or closely
examples of pairs of species that undergo coevolution
herbivores and plants, pollinators and plants, predators and their prey, and parasites and their hosts
In co-evolution, a change in the traits of one
species acts as
a selection pressure on the other species
what is the Red Queen hypothesis and what does it exemplify?
evolution merely permits organisms to maintain their current success, exemplifies the ongoing co-evolution
between a parasite and host
fitness with respect to the coevolution of parasite and host
Hosts better able to resist and tolerate parasitism have greater fitness
Parasites better able to feed, reproduce and find new hosts have greater fitness
sexual reproduction
involves fusion of two gametes from two different parents producing dissimilar offspring
asexual reproduction
involves making exact copies of one parent
disadvantages of sexual reproduction
half of the population (males) are unable to produce offspring, only half of each parent’s genome passed onto offspring disrupting successful parental genomes
advantage of sexual reproduction
increase in genetic variation in the population
advantage of genetic variation
provides the raw material required to continue
adapting in the Red Queen’s arms race between parasites and their hosts
when is asexual reproduction a successful reproductive strategy?
very narrow stable niches or when recolonising disturbed habitats
examples of asexual reproduction in eukaryotes
vegetative cloning in plants and parthenogenic animals that lack fertilisation
where is parthenogenesis common?
cooler climates that are disadvantageous to parasites or regions of low parasite density/diversity
what do organisms that reproduce asexually have mechanisms for?
horizontal gene transfer between individuals, such as the plasmids of bacteria and yeast
Homologous chromosomes are pairs of chromosomes of
methe same size, same centromere position and with the same genes at the same loci
meiosis
mechanism by which variation is increased through the production of haploid gametes by meiosis in gamete mother cells