Biodiversity Definitions

• biodiversity

  the variety of ecosystems and species in an area and the genetic diversity within each species
• ecosystem

  a relatively self-contained, interacting communityof organisms and the environment in which they live and with which they interact. Also includes the interaction between abiotic and biotic factors
• Community

  All of the living organisms, of all species, that are found in a particular ecosystem at a particular time
• habitat

  the place where an organism, a population or community lives
• niche

  the role of an organism in an ecosystem
• species diversity

  The number and relative abundance of species in a biological community.
• hardy weinberg assumptions

  - No change in allele frequency

  - No mutations to create new alleles

  - No selection favouring particular alleles

  - No migration - introducing or removing alleles from the population

  - Large population

  - Mating is random
• Biological Species Concept

  - A species is defined as a group of individuals that interbreed to produce fertile offspring

  - Not based on their similarities in appearance
• Morphological Species Concept

  - Classifies species by their morphological similarities (how they look), not by their ability to reproduce or their DNA
• Ecological Species Concept

  - A species is a group of organisms that are adapted to a particular niche in an ecosystem
• Outline the main features of the domain Archaea

  - Prokaryotic

  - DNA is circular, most have histones, plasmids are present

  - Cell walls present

  - Do not have organelles

  - 70s ribosomes
• Outline the main features of the domain Bacteria

  - Prokaryotic cells

  - DNA is circular, plasmids are present

  - Do not have organelles

  - Ribosomes have prokaryotic and eukaryotic features; transcription is similar to eukarya
• Outline the main features of the domain Eukarya

  - Eukaryotic cells

  - DNA is linear and found within the nucleus, histones are present

  - Cell walls present in plants and fungi

  - Cells have organelles

  - 80s ribosomes
• List the three levels at which biodiversity can be considered

  - Variation of ecosystems or habitats

  - Number and abundance of species

  - Genetic variation within a species
• Describe how random sampling and frame quadrats can be used to assess the abundance of a species

  - The study area is divided into a grid

  - A random number generator is used to obtain coordinates

  - At the coordinates, the frame quadrat is placed on the ground and the abundance of the species within the quadrat is recorded
• How can the abundance of a species within a quadrat be estimated

  - The number or organisms within the quadrat can be counted (species richness)

  - The percentage cover can be estimated. This is useful for species that are very abundant
• When is it appropriate to use transects rather than random sampling of an area

  - Transects are used to measure the change in abundance and distribution of a species across a habitat

  - Rather than within the habitat only

  - A gradual change in an abiotic factor often cause the change in species abundance
• Describe how systematic sampling and a belt transect can be used to assess the abundance and distribution of a species

  - A belt transect is drawn from one part of a habitat to another

  - The frame quadrat is placed at regular intervals along the belt transect and the abundance of a species is measured
• Describe the differences between a line transect and a belt transect

  - Line transect - all organisms touching the line are recorded

  - Belt transect - only organisms in the frame quadrat at each interval are recorded
• Outline the mark-release-recapture method

  - A group of organisms of the target population are caught, counted and marked

  - The marked organisms are released back into their habitat

  - After a period of time, organisms of the same populations are captured again

  - The proportion of marked to unmarked organisms in the captured group is assumed to be the same as the proportion of marked to unmarked in the whole population
• Outline the difference between Pearson's and Spearman's correlation coefficient

  Pearson's - used for linear correlations between two data sets (DF = N-2), quantitative

  Spearman's - works for linear correlations, qualitative data
• Why does biodiversity need to be maintained?

  - To maintain stable ecosystems

  - Ethical reasons

  - Aesthetic reasons

  - Many plant species are yet to be discovered and may contain chemicals that could be used in future medicines
• Describe the difference between continuous and discontinuous variation

  Continuous - shown by a characteristic that can have any value over a range e.g. human height, normal distribution, quantitative data

  Discontinuous - shown by a characteristic that an only take certain values, qualitative data