P2 Biodiversity Flashcards
What is biodiversity?
The variety of living organisms found in a particular place.
What is habitat biodiversity?
The number of habitats in a particular area.
What is species biodiversity?
- Species richness - the number of different types of species living in an area.
- Species evenness - the relative abundance of each species in an area.
Biodiversity increases as the number of types of species increases, and as populations of each species becomes more balanced.
What is genetic biodiversity?
The range of genetic diversity within a species.
- increasing the number of alleles increases the number of genetic differences, and increases biodiversity
- genetic biodiversity helps populations adapt to changes in the environment
What are 6 sampling techniques?
- Quadrats - place randomly, count number of organisms/estimate percentage cover, then scale up to entire habitat (sample plants and slow moving animals).
- Pitfall trap - container placed in the ground at soil level, protected from rainfall by a roof (used to sample small, fast moving organisms on the ground).
- Tullgren funnel - take a sample of soil, light and heat from the funnel causes organisms to move away from the soil, into the container (used to sample small, fast moving organisms on the ground).
- Pooters - suck on a tube to pull organisms into a container (used to sample organisms on the ground, or on trees).
- Sweeping nets (used to sample organisms in the air or in long grass).
- Kick-sampling - place a net on the stream bed so that water flows in, kick the stream bed and organisms will flow into the net (used to sample organisms in streams or rivers).
Advantages and disadvantages of random sampling
- Removes bias
- By chance, the sample may not be representative of the population (minimise this chance by taking a large number of samples)
What are the types of non-random sampling?
- Opportunistic sampling - choose where to sample eg. avoid high, hard to reach areas
- Stratified sampling - the number of samples taken from each area is representative to it’s size.
- Systematic sampling - used to study how biodiversity changes across areas in a habitat, using a belt transect (quadrant sampling at regular intervals)
How is habitat biodiversity measured?
Using Simpsons Index of Biodiversity:
- 0 = no biodiversity (only one species in a habitat)
- 1 = infinite biodiversity
- the higher the index of biodiversity, the more stable a habitat is
- habitats with a small index of biodiversity typically have a smaller number of species that are highly adapted to their environment, they are much less likely to cope with changes in the species presence or their environment
- habitats with a large index of biodiversity usually have larger numbers of species that aren’t adapted to their environment, so they are more likely to cope with change
How is genetic diversity measured?
- By the proportion of polymorphic genes loci (genes with multiple alleles, where loci refers to the position of the gene on the chromosome).
- It is most important to measure genetic diversity in isolated populations, such as zoos where captive breeding takes place, as isolated populations tend to have a lower genetic biodiversity. Therefore it is important to monitor genetic biodiversity to ensure that organisms are still able to adapt and survive if their environment changes.
What are the reasons for maintaining biodiversity?
- Ecological reasons:
- genetic biodiversity helps populations adapt to changes in the environment
- protects keystone species (species that have a large effect on the population), eg. beavers that build damns that flood areas and create new pond habitats - Aesthetic reasons:
- variety of nature brings happiness to people
- provides inspiration, eg. for photography and music - Economic reasons:
- promotes ecotourism
- provides a large amount of resources for drug development
What are the factors affecting biodiversity?
- Human population growth:
- as the human population grows, we need more food, more fuel and more space for houses
- we get these resources by destroying habitats, eg. forests for wood, decreasing species biodiversity - Agriculture:
- monoculture (farmers only growing a single crop) reduces species diversity
- fertilisers used on crops run into water eg. rivers and kill aquatic life, reducing species diversity
- farmers commonly use pesticides that kill a variety of insects - Climate change:
- species that are unable to adapt to climate changes could become extinct
- increases in temperature cause rising sea levels, resulting in flooding that disrupts habitats
What is In Situ conservation?
Conservation that takes place within the natural habitat:
1. Wildlife reserves - provides protecting from humans and excess hunting on land
2. Marine conservation zones - prevent pollution and overfishing
What is Ex Situ conservation?
Conservation that takes place outside the natural habitat:
1. Zoos - protect animals in human controlled environments, educate the general population and use captive breeding programmes to increase a species population, then release the offspring into the wild.
2. Botanic gardens - grow plants in human controlled environments.
3. Seed banks - store a large number of dried seeds, which can be grown at a later date (seeds take up less space than plants, are cheaper to transport, and are less susceptible to disease, however, not all seeds can be stored).
What conservation agreements have been made to maintain biodiversity?
- Convention on International Trade in Endangered Species restricts the trade of endangered species.
- Rio Convention on Biological Diversity - ensures counties that sign enforce strategies to conserve biodiversity.
- Countryside Stewardship Scheme gives money to farmers to conserve the natural habitats.
