Chapter 11 Biodiversity 2.0 Flashcards
What is biodiversity?
The variety of different organisms present within an ecosystem
Describe the importance of maintaining biodiversity
Essential for maintaining a balanced ecosystem for all organisms in order to survive and reproduce.
Describe the importance of measuring biodiveristy
This informs scientists of the species which are present in the area, therefore measuring the level of effect any changes to the environment will have on biodiversity.
What is habitat biodiveristy?
The number of different habitats found within an area.
Describe the impact to species biodiversity if habitat biodiversity increases.
A greater habitat biodiversity means there will be a greater species biodiversity in the area, as each habitat can support a number of different species.
What is species biodiveristy?
Species biodiversity refers to the richness and evenness of a species within a particular area.
What is Species richness?
The number of different species living in a particular area.
What is Species evenness?
A comparison of the numbers of individuals of each species living in a community
What is a community?
All the populations of different species within the same habitat
What is genetic biodiversity?
The variety of genes that make up a species
Why can a greater genetic biodiversity be considered advantageous?
A greater genetic biodiversity within a species allows for better adaption to changing conditions within an environment. Therefore, more organisms are likely to survive and reproduce.
What is sampling?
Taking measurements of a limited number of individual organisms present in an particular area.
What is sampling used to measure?
Sampling provides an estimation of the populations of different species, distribution of a species or measured characteristics throughout the entire species.
What are the different types of sampling?
Random
Non random
What is random sampling?
Selecting an individual by chance so each individual in a population has an equal opportunity of being selected.
This is carried out using random number tables or computers, the investigator has no involvement in deciding which organisms are investigated.
What is Non random sampling?
All organisms have different probabilities of being selected
What are the three techniques of Non random sampling?
Opportunistic
Stratified
Systematic
What is opportunistic non random sampling?
Uses organisms that are readily available.
Weakest form of sampling as it is not representative of the population.
What is stratified non random sampling?
Populations are divided into a number of subgroups based on particular characteristics.
A random sample is then taken from each of these subgroups proportional to its size.
What is systematic non random sampling?
Different areas within an overall habitat are identified and then sampled separately.
How can systematic sampling be carried out?
Using a line transect or belt transect
How is a line transect used to sample organisms?
A line is marked on the ground between two points and samples are taken at specified points.
For example, sampling all the organisms that touch the line or distances of samples away from the line.
How is a belt transect used to sample organisms?
Two parallel lines are marked and samples are taken in the area between the two lines.
Why is a sample never entirely representative of the population?
Selection process may be biased and the organisms selected may not be representative of the whole population.
How can the reliability of the sample be increased?
Sampling bias can be reduced by using random sampling and the effects of chance can be minimised by using a large sample size.
What are the different techniques that can be used to sample animals?
Pooter
Sweep nets
Pitfall traps
Tree beating
Kick sampling
Describe the process of sampling using a Pooter
A Pooter is used to catch small insects, by sucking on a mouthpiece insects are drawn into a chamber where they can then be counted.
Describe the process of sampling using a sweep net
Sweep nets are used to catch insects in areas of long grass
Describe the process of sampling using a pitfall trap
Pitfall traps catch small crawling invertebrates.
A hole is dug into the ground and covered with a roof structure to prevent the trap filling with water.
The trap can then be left overnight so nocturnal species can also be sampled.
Describe the process of sampling using tree beating
This is used to sample invertebrates that live in tree or bushes.
A cloth is stretched out underneath the tree and the tree is then shaken to dislodge invertebrates so they fall onto the sheet to be counted.
Describe the process of sampling using kick sampling
Kick sampling is used to study organisms living in a river. The river bank and bed is disturbed by kicking up the sediment.
A net is set downstream in order to capture any organisms released into flowing water.