Investigating populations and succesion Flashcards
Biodiversity
5
The number of species and the number of individuals of each of the different species within one community
Species Richness
The number of different species within a community
Community
All the individuals of all the species living together in the same area at the same time
Species
Group of similar organism with the same genes that reproduce to produce fertile offspring
Genetic Diversity
Difference in DNA
Niche
Describes where an organism lives and what it does, including what it feeds on and how it interacts with other organisms and the environment.
Habitat
Place where organisms live in an ecosystem
What information is required to calculate an index of diversity for a particular community
Number of species, number of individuals in each species
the number of species present is one way to measure biodiversity. Explain why an index of diversity may be a more useful way to measure
also measures number of individuals of each species. some species may be present in low and high numbers.
2 advantages of using an index of biodiversity rather than an indicator species
you don’t need to identify each species, index considers the number of organisms of each species.
economic argument for maintaining biodiversity
medical/pharmaceutical use, commercial products, tourism, agriculture, saving local forest communities.
farming
Decrease in the variety of plants- fewer plant species. Fewer habitats, decrease in variety of food sources, clearing forest through machinery or pesticides.
Clearing a tropic forest for crops- why does this cause diversity of insects to decrease
lower diversity of plants, few food sources, few habitatas, fewer species of herbivore so few species of carnivores, kills insects
Taxonomy
Theory and practice of classification
Binomial naming system- first word= genus. second word= species name.
classification system:Domain, kingdom, phylum, class, order, family, genus, species
Phylogenetics- all share a common ancestor
courtship
display this behaviour to attract a mate of the same species of opposite sex. Important to ensure reproductive success.
1. Attracts same species of the opposite sex, indication of sexual maturity, stimulates release of gametes. form bond pair
modern classification methods
frequency of measurable or observable characteristics, the base sequence of DNA, base sequence of mRNA, amino acid sequence of proteins encoded by DNA and mRNA
Genetic comparisons and DNA
genetic- made by examination of their DNA, mRNA or of the proteins coded for by this DNA, classified within their genome.
DNA- the more closely related the species the more similar their DNA base sequence.
Comparing the base sequence of a gene provides more information than comparing the amino acid sequence for which the gene codes. Explain why
Longer base sequence than amino acid sequence. Introns, same amino acid may be coded for and a DNA code may be degenerate
Comparing base sequence provides more evolutionary information. Explain why
More bases than amino acids, introns, degenerate code
Population
All the individuals of a given species living together in the same area at the same time
carrying capacity
carrying capacity is the maximum, equilibrium number of organisms of a particular species that can be supported in a stable environment. birth rates and death rates are in equilibrium.
ecosystem
a community made up of living organisms and their interactions with non-living components such as water and mineral soil
why do two species not have exactly the same niche?
different roles within the ecosystem . they would outcompete and one would be more successful.
what happens when niches overlap
species have adaptations that outcompete
method of quadrating
map the area using two tape measures. use a random number generator, place a quadrat at each intersection. can only measure stationary and slow moving populations
why is it incorrect to say that organisms live in the same niche
different organisms may operate the same ecological niche whilst competing until one is eliminated.
how to know when to stop quadrating
calculate running mean, stop sampling when there is little change, enough to carry out a statistical test, a large number to make sure it is reliable, need to make sure it can be completed in the time available.
what rules are there for calculating an estimated population
not biased and random
all data is reliable and representable
not biased and random
all data is reliable and representable
quadrating
density- actual account of all individuals present- limitations- often time consuming, difficult to count
most accurate
percentage cover- the area of the quadrat covered by one species is recorded as a percentage of the total area. used when there are too many individuals to count. overlaying species may occur, total percentage may be over 100%
frequency- proportion of quadrat that contains a particular species. least accurate
factors affecting distribution
Biotic- competition, invasive species, human impact, algae
abiotic- climatic factors, physical factors such as soil and ater PH, aspect (NESW), turbidity and salinity of water.
systemic sampling
transect- recording what species are touching the line at each sampling point
belt transect- placing two parallel lines across, a meter apart and recording what species are found between the two lines
interrupted belt transects- using one line and placing a quadrat down at equally spaced sampling points and recording abundance in each quadrat.
sere
complete succession from pioneer community to climax community- has its own distinctive community of organisms.
mark release recapture
animals are ethically collected, animals are then marked, animals are released and left to redistribute into their population, recapture.
calculation: Number caught the first time x caught the second time/ number caught the second time that were previously marked.
pioneer species
the organisms that first colonise an area
climax community
final stage in an ecological succession- most stable, formed depending on abiotic factors
diversity
the relationship between the number of individual organisms and the number of species within a community.
stages of succession
colonization by named pioneer species, change in environment, enables other named species to colonise, change in diversity, stability increases, climac community represented by named species.
secondary succession occurs after forest fire or clearance of agricultural land.
deflected succession- when climax community is prevented from being established. community maintained under such conditions is known as a plagioclimax.
