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1.6 Biodiversity

Classification/Adaptations/Genetics

Niche: The role of an organism within its habitat or ecosystem. Species which occupy the same niche will compete with each other for resources such as food/shelter.

Keep- Kingdom

Pond- Phylum
Clean- Class
Or- Order
Frogs- Family
Get- Genus
Sick- Species

Simpsons index of biodiversity:

D=

N(N-1)

Σn(n-1)​​

Adaptations in ecosystems:

-Anatomical adaptations mean differences in the components of animals bodies.

-Behavioural adaptations describe differences in behaviour (such as aggression/mating calls)

-Physiological adaptations such as differences in the way things are regulated in the body (homeostasis)

Impacts of agriculture:

Humans typically reduce biodiversity within an area by growing monocultured crops (one species) and using heavy pesticides and herbicides. Farmland drainage leaks nitrates and phosphates into the soil, contributing to further reductions in biodiversity.

Humans can increase biodiversity by:

-Planting multiple crops at once instead of monocultures

-Use effective draining mechanisms

-Plant trees and maintain A-shaped hedgerows

-Reduced use of pesticides and herbicides

Biodiversity: The variety of different organisms. This means how many organisms in total, as well as how many individuals of each species in what kind of distribution. A high biodiversity value will mean a large number of different organisms.

N = Total number of organisms

n = Total number of organisms of each species

Further human impacts:

-Deforestation (loss of habitat)

-Hunting (risks of extinction)

-Emissions (acid rains/fuel emissions)

-Building (loss of habitat)

Variation within populations:

  • Crossing over during meiosis and the random assortment of chromosomes causes variation between individuals to arise.

  • Mutation (which can be random or induced by mutagenic agents) causes random changes to the genetic code, causing further variation.

  • Natural selection means advantageous alleles will be more likely to be passed on to the offspring thereby increasing allelic frequency.

Gene technology:

The sequence of amino acids that make up proteins translated from specific genes can be read, and an mRNA sequence can be derived from it.

Fertilisers, runoff and eutrophication:

Eutrophication describes the long term damaging effect to aquatic ecosystems in rivers and lakes. Farm and industrial waste have a high nitrogen content, and so promote algal growth on the waters surface. 

Algal bloom thickens the layer of algae, so much so that light can no longer penetrate the water beneath. As a result, aquatic plants and algae die due to lack of available light for photosynthesis.

This build up of organic waste promotes the growth of decomposers, or saprobionts. These digest the organic material, but require oxygen to aerobically do so. As a result, the oxygen concentration of the water decreases and promotes the death of aquatic animals such as fish and insects.

Further deoxygenation of the water promotes the activity of anaerobic bacteria, which produce hydrogen sulphide and methane, further worsening the water supply.

Comparing genomes and biodiversity:

  • Sequencing of genomes and then alignment comparison will allow a measure of how similar two genomes are.

  • Comparing visible characteristics or behaviour could help determine how similar organisms are.

Issues with comparing genomes:​

  • Characteristics coded for by not just one gene (may be more than one gene)

  • These similar characteristics (behavioural e.g.) could have arisen due to environmental effects.

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