Topic 4- Biodiversity and Natural Resources

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  • Created by: Emily
  • Created on: 15-01-11 12:17

Species and Biodiversity

Biodiversity: Variety of different organisms within a habitat. Two things to consider are ....

  • Species Richness - Number of different species with an area at a particular time.
  • Genetic Diversity - Genetic Variation within a species

Species: A group of organisms with so many features in common that they can mate and produce sexually viable offspring.

Measuring...

  • Species richness - quadrats randomly placed in an area - all species found in area are used to estimate the total species richness.
  • Measuring Genetic Diversity - Find the number of different alleles in a gene pool (total number of genes a species has)

Endemism: A situation where species is found in only one particular area.

Taxonomic Grouping

Molecular Phylogeny: Compares the structure of a particular molecule from different organisms to discover their degree of evoluntionary relatedness. There have been three catagories identified

  • Bacteria (prokaryotic)
  • Archaeo
  • Eukaryotic

Species eveness: When most species have simular adundances there is a high eveness ( no single species dominants the community)

Biodiversity Hotspot: contains the largest proportion of the worlds plant species.

Natural Selection and Evolution

Niche: The way a species makes use of its environment. All species sharing a habitat will have a different niche. If two different species in the same environment share the same niche then there will be competition between toe 2, The better adapted will survive.

Types of Adaption (improve the chances of survival)

Anatomical - physical Adaption (cacti have highly modified leaves called spines. The reduction in size decreases the number of pore though which water can be lost.) (bumble bees have long tongues which stick to nectar)

Behavioural - Changes in behaviour/ actions ( a single cell organism reverses it direction if it accidently moves into an unfavourable conditions from favourable conditions)

Physiological- Changes in internal functioning of organism (people who move from sea level to high up a mountain slowly increase their oxygen carrying capacity by producing more red blood cells)

Co-adaption: When 2 things become dependant on one another and more and more closely adapted. (plant and pollinator)

Natural Selection

Can lead to adaption and evolution. It is the survival of individuals in a population because they have the alleles that improve their chances of survival and reproduction. (survival of the fittest - characteristics that give them the advantage)

Evolution - Change in the frequency of certain alleles in a gene pool over time due to natural selection.

  • Population of organisms shows genetic diversity due to have a variety of alleles.
  • Environmental conditions change.
  • Natural selection removes indiviudals whith alleles with are not advantageous.
  • Remaining individuals grow and reproduce passing on advatangeous alleles.
  • Frequency of these alleles increase.

For animals to be adaptable in new conditions is dependant on

  • Strength of selection pressures
  • Size of gene pool
  • Reproductive rate of organism

A hierarchical System

A taxonimcal herarchy is created which is a series or groups in which members share one or more thing in common

  • Kingdom - Plant/animal
  • Phylum - Invertabraw/vertabrae
  • Class - Insect/

Comments

tashfeen

Dese notes are amazin..... thanks a lot....!!!!!!!!!!!!:D

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