4.2.1 - Biodiversity (set A - Types Of Biodiversity + Sampling) Flashcards
Define biodiversity?
The variety of all living organisms present in an area - includes plants, animals, fungi and other living things
- essential for maintaining balanced ecosystems for all organisms
Explain the role of measuring biodiversity?
Important role in conservation - informs scientists of the species present in an area
- information can be used to measure the effect of any changes to an environment (eg human activity, disease or climate change)
Give the 3 different levels biodiversity can be studied?
- habitat biodiversity
- species biodiversity
- genetic biodiversity
Outline and explain habitat biodiversity?
Refers to number of different habitats found within an area - in general the greater the habitat biodiversity, the greater the species biodiversity will be within the area as the habitat can support more species
- uk habitats include meadows,woodland, streams and sand dunes (large habitat biodiversity) - where as Antartica has low (covered entirely by ice sheet)
What are the 2 components of species biodiversity?
- species richness - number of different species living in a particular area
- species evenness - comparison of the number of individuals of each species living in a community
define community?
All the populations of living organisms in a particular habitat
Explain with an example how an area can differ in species biodiversity even if it has the same number of species?
A cornfield and a grass meadow may both contain 20 species - however the corn will make up 95% of the community with the remaining 5% made up of other organisms like weed plants and insects - in the grass meadow the species will be more balanced in their populations
Outline and explain genetic biodiversity?
Refers to the variety of genes that make up a species - different versions of genes (alleles) lead to genetic biodiversity within a species
- greater genetic biodiversity within a species allows for better adaption to a changing environments
Explain what sampling is?
Taking measurements of a limited number of individual organisms present in a particular area - can be used to estimate number of organisms within an area
- two ways random and non-random
Explain random sampling?
Selecting individuals by chance (each individual in population has an equal likelihood of selection)
- can use random number tables or computers
Explain non-random sampling?
The sample is not chosen at random - divided into 3 types opportunistic, stratified and systematic
Explain opportunistic sampling?
weakest form of sampling - may not be representative of the population
uses organisms that are conveniently available
Explain stratified sampling?
Some populations can be divided into a number of strata (sub groups) based on a particular characteristic
- random sample then taken from each of these strata
Explain systematic sampling?
Different areas within an overall habitat are identified, which are then sampled separately - often carried out using a line or belt transect
- may be used if studying how plant species change as you move inland from the sea for example
Explain sampling bias?
Selection process may be biased (maybe by accident or deliberately) - can be reduced by using random sampling
- example would be choosing a particular area that has more flowers because it looks more interesting
Impacts reliability
Explain how chance can impact reliability?
Organism selected may by chance not be representative of the whole population - can be reduced by using a larger sample size which increases reliability of results
- eg studying sizes of worms - first 5 you find could be the longest in the habitat
Explain 4 techniques for sampling animals and plants?
- pooter - used to catch small insects by sucking on mouthpiece which draws insect into a holding chamber
- sweep nets - used to catch insects in long grass
- pitfall traps - used to catch small invertebrates, which fall into small hole in ground (often left overnight)
- quadrats - used for plants
Explain how quadrats are used for sampling?
Frame quadrat consists of a grid of equal sections - type and number of species within each section is recorded this is often paired with a random sampling technique
- another type is point quadrats
Explain how animal population size can be estimated?
Technique called capture-mark-release-recapture can be used
- by comparing the number of marked individuals with the number of unmarked individuals in the second sample - scientists can estimate population size
Explain how species evenness can be calculated?
By comparing the total number of each organism present - populations of plants/animals that are similar in size or density represent an even community and high species evenness
Explain the habitat features of an environment with low biodiversity?
- relatively few successful species
- nature of environment is stressful/extreme
- species often have very specific adaptions for the environment
- relatively simple food webs
Explain the habitat features of an environment with high biodiversity?
- large number of successful species
- nature of environment is benign
- species have very few specific adaptions for the environment
- complex food webs
