Topic 4C: Diversity and Classification Flashcards
Definition: Phylogeny
The study of the evolutionary history of groups of organisms
What do the branches of a phylogenetic tree symbolise?
Common ancestors shared between different species. The closer the branch point, the more recent the common ancestor.
Definition: Taxonomy
The organisation of organisms into different groups called.
Definition: Taxa
The different groups used to classify organisms. Each group is known as a taxon.
Definition: Heirarchy
The way in which groups are arranged, to prevent overlap with an organism only belonging to one group.
Classification
Domain Kingdom Phylum Class Order Family Genus Species
The binomial system
The system used to name organisms.
Homo sapiens
What is courtship behaviour?
An action carried out by organisms to attract a mate of the right species.
Courtship behaviour is species specific allowing members of the same species to recognise each other, preventing interbreeding which makes reproduction more successful.
Classification: Courtship behaviour
Courtship behaviour is species specific, meaning courtship behaviour can be used to classify organisms. The more closely related species are, the more similar their courtship behaviour.
Classification: Genome sequencing
The entire base sequence of an organism’s DNA can be determined, and compared with that of another organism to see how closely related they are. Closely related species will have a higher percentage of similarity in their DNA base sequence.
Classification: Comparing amino acid sequence
Related organisms will have similar DNA sequences and so similar amino acid sequence in their proteins.
Classification: Immunological comparisons
If organisms are similar they will have similar proteins. These proteins will bind to the same antibodies. Therefore, by seeing if antibodies will bind to proteins from different organisms, you can see how similar they are.
What are the causes of variation?
- Genetic factors
* Environmental factors
Definition: Variation
The differences that exist between individuals.
Why should random sampling be used?
To ensure that results aren’t biased.
What is the shape of a normal distribution graph?
Bell-shaped
Definition: Biodiversity
The variety of living organisms in an area.
Definition: Habitat
The place where organisms live
Definition: Community
All the populations of different species in a habitat.
Definition: Species richness
A measure of the number of different species in a community.
How do you calculate biodiversity?
Use the index of diversity equation.
Equation: Index of diversity
d = N(N-1) / Σ n(n-1)
d = index of diversity N = total number of organisms of all species n = total number of organisms of one species
Impact of agriculture on biodiversity: Woodland clearance
- Used to increase the area of farmland.
- Reduces number of trees and destroys habitats, meaning there is no shelter or food available.
- Therefore, species die or are forced to migrate, reducing biodiversity.
Impact of agriculture on biodiversity: Hedgerow removal
- Used to increase the area of farmland.
- Destroys habitats, meaning there is no shelter or food available.
- Therefore, species die or are forced to migrate, reducing biodiversity
Impact of agriculture on biodiversity: Pesticides
- Used to kill pests that feed on crops.
- This directly kills organisms and also destroys the food source of animals which feed on these organisms.
- Therefore, biodiversity decreases.
Impact of agriculture on biodiversity: Herbicides
- Chemicals used to kill weeds.
- Reduces plant diversity and means less animals are supported by these plants.
- Therefore, biodiversity decreases.
Impact of agriculture on biodiversity: Monoculture
- When farms only grow one type of plant.
- Reduces biodiversity directly and also supports less organisms.
- Therefore, biodiversity is reduced.
Why are conservation schemes used?
To increase biodiversity in order to provide us with new sources of materials and medicines, and to benefit agriculture.
