What is Biodiversity?

This page introduces fundamental concepts related to biodiversity in GCSE Biology AQA and genetic diversity as level of biology.

Biodiversity refers to the variety of life in an ecosystem, encompassing both habitat diversity and species diversity. Species diversity considers both the number of different species present and the abundance of individuals within each species. Genetic diversity relates to the variety of alleles within a species population.

Definition: Biodiversity is the variety of life in an ecosystem, including the diversity of habitats and species.

A high level of species diversity contributes to ecosystem stability. It reduces the likelihood of species extinction due to greater genetic diversity and minimizes the impact of a single species loss on the food chain.

Highlight: High species diversity leads to more stable ecosystems that are resilient to change.

The Species Diversity Index is used to quantify biodiversity in an area, taking into account both the number of species and their relative abundances.

Example: Deforestation negatively impacts biodiversity by reducing plant species diversity, habitat variety, and food sources, which in turn decreases animal species diversity.

Agriculture also lowers species diversity through deforestation, monoculture practices, selective breeding, and pesticide use.

Vocabulary: Monoculture refers to the agricultural practice of growing a single crop or raising a single species of livestock in a given area.

Evolutionary Relationships and Variation

This page focuses on methods for determining phylogenetic classification evolutionary relationships and understanding variation within and between species.

DNA Hybridization is a technique used to compare the genetic similarity between species. It involves labeling DNA from one species, mixing it with DNA from another species, and measuring the temperature required to separate the hybrid DNA strands.

Highlight: A higher temperature required to separate hybrid DNA indicates more hydrogen bonds, more complementary base pairing, and thus more closely related species.

Amino Acid Sequence Comparison involves analyzing the sequence of amino acids in the same protein across different species. This method is less informative than DNA sequence comparison because it doesn't provide information on introns and the genetic code is degenerate.

Protein Shape Comparison uses immunological techniques to compare the shape of the same protein in different species. This method involves creating antibodies against a protein from one species and testing their reaction with the same protein from another species.

Example: Antibodies created against albumin from Species A are used to test the similarity of albumin in Species B. More precipitate formation indicates more similar protein shapes and more closely related species.

Variation refers to differences in characteristics between organisms and can be classified as:

• Intraspecific: differences within the same species
• Interspecific: differences between different species

Definition: Intraspecific variation refers to differences between organisms of the same species, while interspecific variation refers to differences between organisms of different species.

Causes of variation include both genetic and environmental factors.