Classification and Biodiversity



Process by which organisms are put into groups based on various features. The current syatem of classification uses 8 taxa:









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Scientific Names

All living things have a binomial name (It will always have two words)

The Binomial system is genus then species. The genus name has a capital letter and the species name does not.

Why do we use scientific names?

To avoid confusion so people know what organism is being described.

Aids communication between international scientists.

Different areas have different common names for plants

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Competion and Adaptations

Interspecific Competition - Between different species for a resource

Intraspecific Competition - Between members of the same species

Plants may compete for:

Water, Sunlight, Nutrients, Space

Animals my compete for:

Food, Water, Teritory, Mates, Shelter

Organisms have morphological and behavioral adaptations which enable them to survive in their environment

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To find out what species are present and the size of the population of each of them would be ideal but would take too long.

Random Sampling

Random sampling is used when an area looks uniform or as though the species distribution is patchy with no clear pattern.

You may miss species in this method. Always record species present even if they do not fall within a quadrat.

Random sampling should eliminate bias.

Systematic Sampling

If you want to investigate how vegetation changes as the land/soil type changes, a belt transect will give you the data you need.

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Estimating the Population Size of Animals

Mark, Release and Recapture

  • Catch as many individuals as possible and record the number
  • Mark individuals
  • Return to habitat and allow to mix in with the rest of the population
  • Capture a second sample and record total number as well as number of marked individuals

Estimated Population Size= Number in First Sample X Number in Second Sample

    Number of Marked Individuals in Second Sample

Assumptions Made

Mark given will not jepardise survival

No immigrations or births between sampling

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Biodiversity is the number of diffeent species in a particular area.

Biodiversity is important because it leads to stable ecosystems. Ecosystems help to regulate the amosphere, regulate water supply, regulate nutrient cycles and provide fertile soil. This means biodiversity is important for food, industrial materials, medicines and human well being.

Biodiversity is at risk because more and more species are becoming extinct due to habitat loss. Habitats are being destroyed due to building, quarrying, dumping rubbish and agriculture. In the last 50 years the population of animal has dropped by 60%.

Biodiversity is being protected by:

CITES (agreement to prevent trade in endagered species)

SSSI (protecting sites of special scientific intrest)

Captive breeding programs and seed banks

National parks and local biodiversity conservation schemes

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Biological Control-Key words

Biological control is the use of living organisms to control the population of pest species.

Alien species are species brought in from a different country

Natural enemies are the natural predator of the pest

Beneficial insects are insects that are actively benefical to the crop (eg. pollinators)

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Biological Control-Advantages and Disadvantages

Advantages of Biological Control

No chemicals involved

Reduces pest population rather than wiping them out so it results in a stable ecosystem

If carefully selected the control agent will only attack the pest

Disadvantages of Biological Control

Alien species may have no natural enemies and may grow out of control

May compete with an existing species causing it to die out, lowering biodiversity

May bring a disease that affects existing populations

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