species, taxonomy & biodiversity Flashcards
define ‘species’
a group of similar organisms able to reproduce to give fertile offspring
define ‘courtship behaviour’
a seq. of actions which is unique to each species
types of acts classified as courtship behaviour
- seq of dance moves
- display of colours
- release of pheromones
- sounds
the importance of courtship behaviour
- organisms can recognise sexually mature members of their own species
- ensures successful species recognition —> courtship rituals genetically determined —> the more similar a courtship sequence, the more closely related species are
- ensures survival of offspring —> form pair bond —> strong, healthy male identified & advantageous alleles passed onto offspring
define ‘hierarchy’
smaller groups arranged from within larger groups with no overlap between groups
phylogenetic classification
arranges species into groups according to their evolutionary origins & relationships
the names of the taxons in the classification pyramid
(demanding kids prefer chips over floppy green spinach)
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
which system is used to identify species?
- the binomial system
1) Genus 2) species
define ‘species diversity’
no. of diff species & no of individuals of each species within 1 community
define ‘genetic diversity’
the no. of diff alleles of genes in a population
define ‘ecosystem diversity’
the range of diff. habitats in an area
define ‘species richness’
the no. of diff species within a habitat
species index =
N(N-1) / Sum n(n-1)
N = total no. of organisms
n = total no. of organisms of each species
is low biodiversity a cause for concern?
- no —> arctics and deserts
- a decrease in biodiversity = cause for concern
impact of agriculture
- selective breeding
- hedgerow removal
- woodland clearance
- use of monoculture
ways of investigating diversity
1 - the base seq of DNA
2 - the base seq of mRNA
3 - the aa seq
index of diversity > species richness
index of diversity also measures abundance of each species —> useful bc there may be many of some species
ways to standardise the sampling procedure
- same size of sampled area
- samples taken at same time of day
how to ensure index diversity is representative of each habitat
- random samples
- large no. of samples
how to find the total no. of individuals of a species in a field/meadow
1 - determine area of the plot
2 - calculate total area of meadow/field
3 - divide area of meadow by area of plot
advantages of replanting hedgerows
- greater diversity —> increase in predators of pests
- increase in predators of pests —> more yield
disadvantages of replanting hedgerows
- reduced land area for growth of crops
- greater diversity —> increase in population of pests
- increased population of pests —> less yield
effect of non-native species
- out-competes native species
- some populations of native species go extinct
effect of herbicide
- low conc. kills weeds —> more yield
- high conc = toxic to crops
correlation doesn’t mean..
causation (may be some other factor)
which test do u carry out to tell if a correlation is significant?
find correlation coefficient
