AS OCR Biodiversity module notes

These notes are not just tailored to the spec, because I feel it is important to have background knowledge on this module, I would recommend Crash Course Geology on YouTube for effortless revision :), Thank you for reading

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  • Created by: Cymbeline
  • Created on: 07-04-13 13:50
Preview of AS OCR Biodiversity module notes

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Species: a group of individual organisms very similar in appearance, anatomy, physiology,
biochemistry and genetics, whose members are able to interbreed freely to produce fertile
Physiology is the mechanisms in organisms e.g. muscle contraction
Habitat/ecosystem: the place where an organism lives
Biodiversity: the variety of life or range of living organisms to be found
Random sampling: studying a small part of the habitat and assuming it contains a representative set
of species that can be applied to the whole habitat. The sample sites must be chosen at random.
Systematic: sampling in which the observer does not decide where to take measurements
Species richness: the number of species present in a habitat
Species evenness: a measure of the relative abundance of individuals in each species
Simpson diversity index: a formula used to measure the diversity of a habitat
Biological classification: the process of sorting living things into groups. Natural classification does
this by grouping things according to how closely related they are. Natural classification reflects
evolutionary relationships.
Artificial Classification: taxa created by humans for convenience such as ordering flowers by colour
Taxonomy: the study of the principles of classification. Prior to history, when scientists classified
organisms by analogous or homoplasic traits (similarity of looks).
Phylogeny: the study of the evolutionary relationships between organisms
Monophyletic: organisms belonging to the same phylogenetic group
Common ancestor: an ancestor shared by two or more taxonomic groups, do not survive today
The binomial system: uses two names to identify each species: the genus name and the species
A dichotomous key: uses a series of questions with two alternative answers to help you identify a
Variation: the presence of variety of differences between individuals
Genetic variation: caused by differences between the genes and combinations of genes or alleles
Continuous variation: variation in which there is a full range of intermediate phenotypes between
two extremes. This mainly concerns environmental variation.
Discontinuous variation: variation in which there are discrete groups of phenotypes with no or
very few individuals in between. This mainly concerns genetic variation.

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Adaptation: feature that enhances survival and long term reproductive success
Selective pressure: a factor that causes individuals to reproduce successfully.
Selective advantage: a factor that enables individuals to compete, adapt and reproduce.…read more

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Take samples at regular distances across habitats
o Use random number generators to plot coordinates in a habitat
When comparing two habitats of the same study, the sample sizes should be equal.
Trees-percentage of ground cover,large plants-species per unit area, herbs-percentage
Random sampling can miss rarities so a visual survey is done and would be recorded as
presence with no abundance and cannot be used for statistics.…read more

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An evolutionary/phylogenetic tree is a hierarchy that shows common ancestors at branch points and
evolutionary distances between closed related organisms that branch off when evolved.
Prokaryotes (bacteria and blue-green algae) like viruses, have no nucleus, histones,
membrane-bound organelles or chromosomes due to pre-evolution; instead have loop of naked
DNA. They are smaller the eukaryotes and have smaller ribosomes, they respire with mesosomes not
mitochondria and maybe free-living or parasitic.…read more

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The EIA has made it illegal to interfere with a protected species without a license, because
loss would cause a major impact on the environment
A dichotomous key will have one question fewer than the possible species it can identify
Individuals don't evolve, individuals are selected and populations evolve
Biochemistry can suggest evolutionary relationships:
o Cytochrome c : a protein in all organisms used for respiration, but varies in amino acid
sequence, the more differences found between them, the less closely related the
two species,…read more

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Speciation usually takes many years but depends on the pass rate of generations, which may
be a few hours in thriving bacteria.
Speciation that increases diversity may occur when:
1. A population migrates to new habitat
2. An environmental change affects group of the population
3. A reproductive barrier, is inherited until they cannot interbreed.…read more

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Growth of fuel and food
o Regulates atmosphere and climate for respiration
o Purification of water
o Fertile soil and pollination
o Recycling of wastes
o Aesthetic-improving emotional health via beauty of nature
o Like humans, all organisms have the right to survive
Genetic erosion is caused where there is damage to the ecosystem that affects biodiversity
and thus the gene pool and genetic variation, this way monoculture can lead to extinction.…read more

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Facilitates scientific research
Conservation must include the human community to avoid conflicts:
o People leaving litter or feeding animals
o Illegal harvest of plants or hunting
o Animals that escape the reserve may raid farmers crops
Conservation exists in the UK as 14 National Parks and over 6000 SSSIs, which use traditional
methods to rebuild biodiversity. Botanical gardens conserve endangered plant species.
Captive breeding programmes repopulate by providing a veterinary service and protection
from predators.…read more

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There are three stages to EIA
o The developer makes an environmental statement assessing effect on local
o environmental statement is publicised
o authority considers it into their decision
The EIA aims to keep clarity of the effects of a development to the developer, planning
authority and local community so that design of the final proposal is more environmentally
acceptable…read more


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