Biodiversity 4.2 Flashcards
What is biodiversity?
A measure of the variation found in the living world
What is a habitat?
Where an organism lives
What is a species?
A group of organisms that can freely interbreed to produce fertile offspring
What are the three types of biodiversity?
- habitiat
- species
- genetic
Describe habitat bidiversity
The range of habitats in which different species live
Describe genetic biodiversity
The variation between individuals belonging to the same species which ensures we do not look identical
Describe species biodiversity
The range and number of organisms found in a habitat
What are the 4 types of sampling?
- random
- opportunistic
- stratified
- systematic
Explain random sampling
It is sample sites inside a habitat that are randomly selected by using randomly generated numbers as coordinates for your sample
Explain opportunistic sampling
When the researcher makes sampling decisions based on prior knowledge or during the process of collecting data, they may deliberately sample an area that contains a certain species
Explain stratified sampling
Dividing a habitat into areas which appear different and sampleing them a proportionate amount of times in proportion to how much of each habitat there is
Explain systematic sampling
When samples are taken at fixed intervals across the habitat, line transect and belt transect are systematic techniques
What are the advantages of random sampling?
Ensures the data is not biased by selective sampling
What are the disadvantages of random sampling?
- may not cober all areas of the habitat equally
- low presence may be missed
- underestimates biodiversity
What are the advanatges of opportunistic sampling?
Easier and quicker than random sampling
What are the disadvantages of opportunistic sampling?
- the data may be biased
- large colourful species may entice researcher to include that species
- leads to overestimate of importance of the species
- overestimates biodiversity
What are the advantages of stratified sampling?
- ensures that all different areas of the habitat are sampled
- species are not under represented
What are the disadvantages of stratified sampling?
- there is the possibility that it leads to over representation
Eg/ disproporionate number of samples taken in a small area
What are the advantages of systematic sampling?
- useful when the habitat shows a clear gradient on some environmental factor
Eg/ getting drier away from the pond
What are the disadvantages of systematic sampling?
- only species on the line are recorded
- some species may be missed
- leads to underestimate of biodiversity
What is the preparation of sampling a habitat?
- suitable clothing
- suitable footwear
- apparatus needed to carry out sampling
- appropriate key to identify species
- camera to record specimens
- pen and paper to record observations
What apparatus is used for sampling plants?
- quadrat
- measuring tape
- clipboard, pen, paper
- camera
What are the methods for catching invertebrates?
- sweep netting with a stout net
- pooter
- spred a white sheet under a tree and nock it with a stout stick
- pitfall trap
- a light trap (tullgren funnel)
What are the methods for cathcing small animals?
- longworth trap
- capture recapture
What is the equation for capture recapture?
N = (MxC) / R
What does N represent in the capture recapture equation?
Population size
What does M represent in the capture recapture equation?
Number of in first sample
What does C represent in the capture recapture equation?
Number in second sample
What does R represent in the capture recapture equation?
Number of marked in the recapture
What is an allele?
A version of a gene
What is a locus?
The position of that gene on a chromosome
What is a polymorphic gene locus?
A locus that has more than two alleles
What is Simpson’s index of biodiversity?
A measure of the diversity of a habitat
What is the formula for simpson’s index of diversity?
D = 1 - (E (n/N)^2)
What is species eveness?
A measure of how evenly represented the species are
What is species richness?
A measure of how many different species are presented
How do you survey the frequency of plants?
- record the percentage cover of each plant species
- for large plants count the number of individuals
How do you measure the density of animals in a habitat?
- large animals can be counted by observation
- smaller animals can be counted by using capture recapture
What does a higher value mean on Simpson’s index?
A higher biodiversity
What does a lower value mean on Simpson’s index?
A lower biodiversity
How do you calculate genetic diversity?
When a particular feature shows variation between individuals
What is climate change?
Significant, long lasting changes in weather patterns
What is monoculture?
Acrop consisting of one strain of one species
How have humans affected the natural world?
- learned to use the environment to our advantage
- we alter the ecosystem to provide ourselves with food
- we destroy and fragment nabitats
- we are using more of the earths resources
- we pollute the atmosphere
How has agriculture affected biodiversity?
We reduce the size of habitats and population size of any wild species in those habitats, this reduces genetic diversity meaning that species have less capacity to adapt
How does selective beeding reduce genetic diversity?
Farmers select particular traits which means that some characteristics are ignored which means genetic diversity decreases
How does climate change affect species?
As climate changes they are less able to adapt to the changes in temperature and rainfall and this means there will be slow migration of populations towards the poles
What are the obstructions to migration?
- major human developments
- agricultural land
- large bodies of water
- mountain range
When does extinction occur?
When the last living member of a species dies and the species ceases to exist
What are the statistics to do with extinction?
- there have been over 800 recorded extinctions since the year 1500
- up to 20% of the species alive today could be extinct by 2023
- the current rate of extinction is at least as fast as in any extinction rate
What is a keystone species?
One that has a disproportionate effect upon its environment relative to its abundance
What is soil depletion?
The loss of soil fertility caused by removal of minerals by continuous cropping
Why is it bad if genetic biodiversity declines?
It means that we could lose the natural solutions to some of our problems
What are economic reasons to maintain biodiversity?
- regulation of the atmosphere and climate
- formation and fertilisation of the soil
- recycling of nutrients
- crop pollination
- growth of timber, food and fuel
- purification and retention of water
What are the aesthetic reasons to maintain biodiversity?
We experience a feeling of joy and wellbeing when observing variations of nature
What are the ecological reasons for maintaining biodiversity?
- minimise disruption to food chain
- minimise disruption to nutrient cycle
- minimise disruption to pollinators
- protect keystone species
What is In situ conservation?
It is inside an organism’s natural habitat and include marine conservation and wild reserves
What is Ex situ conservations?
It removes organisms from their natural habitat and includes seed banks, botanic gardens and captive breeding programs?
How do wildlife reserves help?
- protect an area
- control grazing
- restricts human access
- controls poaching
- removes invasive species
- feeding animals until they reach reproductive age
How does marine conservation help?
- Lundy islands in Devon
- protects habitats (seaweed)
- creates areas of refuge so populations can increase in size
How do botanic gardens help?
- plant species grown successfully with the right conditions and care
- provides the plants with nutrients, minerals, water, removes pests and correct temperature
How do seed banks help?
- seeds are stored in underground vaults at the right conditions
- dry, dark, -20 degrees
- slows rate that they lose their ability to germinate
- backup in case of extinction
How do captive breeding programmes help?
- offspring are produced in a human controlled environment
- often managed by zoos or aquatic centres
- provides animals with shelter, food, no predators, vets and breeding partners
What are the problems with captive breeding?
- maintaining genetic diversity
- low resistance to disease/ new diseases in the wild
- behaviour, not knowing how to hunt
- natural habitat may be lost
- genetic differences to animals in the wild might mean they can’t interbreed
