Biodiversity and classification 3.4.5/6

Heirarchial taxonomic system

(Largest to smallest)
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. (King prawn curry or fat greasy sausage)

There are 3 domains: Bacteria (prokaryotic), Archaea (prokaryotic), Eukarya (eukaryotic).

Binomial nomenclature

Each species has a 2-part binomial name in Latin. The name is italicised if typed and underlined if written down.

Genus (uppercase first letter) species (lowercase).

Courtship behaviours

Courtship behaviours help animals attract mates through displays and signals that are species specific. It enables recognition of the same species and leads to successful mating and the production of fertile offspring, preventing wasteful interspecies breeding.

Phylogeny

Phylogenetic classification is based on evolutionary relationships between organisms and their ancestors, classifying species into groups. A phylogenetic tree reveals how closely related organisms are by showing the most recent common ancestor.

Early classification used physical characteristics to determine phylogeny, however this was not accurate so we now use molecular comparisons (DNA genome), development studies (embryonic differences), anatomical examinations (physical characteristics) and behavioural analysis.

Biodiversity

Biodiversity is the variety of organisms in an area. High genetic biodiversity (high variation in alleles within a population of a species).

The index of diversity is a way of measuring biodiversity: Index of diversity = (N(N-1))/(En(n-1))
N = Total number of organisms of all species
n = Total number of organisms of one species
E = sum of

Types of species variation

Interspecific variation is the variation between different species due to different genes causing different physical traits and adaptations and environmental factors such as climate and diet.

Intraspecific variation is variation between individuals within one species due to different alleles and environmental factors.

Biodiversity measures

Species richness - A measure of the number of different species in a community. It can be measured by taking random samples and counting the number of species present.

Species evenness - A comparison of the number of individuals in each species in a community. It is measured by taking random samples and counting how many individuals are in each species.

Human population growth

Human population growth impacts biodiversity:

Deforestation for development destroys habitats.
Overuse of resources causes species to decline.
Urban sprawls isolate wildlife populations, limiting breeding and decreasing genetic diversity.
Pollution kills species and harms habitats.

Agricultural practices

Some agricultural methods decrease biodiversity:

Monocultures is growing a single crop over a large area, this decreases the species richness.
Herbicides/pesticides may harm species or runoff into water sources.
Removal of hedgerows destroys habitats and plant species.

Conservation schemes

Maintaining hedgerows, reducing pesticide and herbicide use, using organic fertilisers and rotating crops.

Genetic diversity

A high genetic biodiversity means there is a large variety of alleles in the population's gene pool. Genetic diversity can be compared by the frequency of measurable characteristics, or using comparative biochemistry. Comparative biochemistry studies molecular aspects of organisms such as the DNA or mRNA base sequence and amino acid sequence.