4.2.1 - Biodiversity Flashcards
What is biodiversity?
The variety of living organisms present in an area
What are the three levels of biodiversitry?
Habitat biodiversity, species biodiversity, genetic biodiversity
What is habitat biodiversity?
The number of different habitats found within an area
What are the two components of species biodiversity?
Species richness and species evenness
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 living organisms in a particular habitat
What is genetic biodiversity?
The variety of genes that make up a species.
What is sampling?
Taking measurements of a limited number of individual organisms present in a particular area
What are the three main types of non-random sampling?
Opportunistic, stratified, and systematic
What may cause a sample to not be reliable?
- Sampling bias (the selection process may be biased)
- Chance (the organisms selected may be, by chance, not representative of the whole population)
How can the impact of chance on a sample be reduced?
Increasing the sample size
Give examples of equipment that can be used to sample animals
Pooter, sweep net, pitfall trap, tree beating, kick sampling
What are plants normally sampled with?
A quadrat
What are the two types of quadrat?
Point quadrat and frame quadrat
Describe a point quadrat
Consists of a frame containing a horizontal bar. At set intervals along the bar, long pins can be pushed through the bar to reach the ground. Each species of plant the pin touches is recorded
Describe a frame quadrat
Consists of a square frame divided into a grid of equal sections. The type and number of species within each section of the quadrat is recorded
What are the main three ways of using a frame quadrat to sample plant population?
Working out density, working out frequency, and working out percentage cover
What are abiotic factors?
The non-living conditions in a habitat
How can wind speed be measured?
Using an anemometer
How can light intensity be measured?
Using a light meter
How can relative humidity be measured?
Using a humidity sensor
How can pH be measured?
Using a pH probe
How can temperature be measured?
Using a temperature probe
How can oxygen content be measured?
Using a dissolved oxygen probe
How can species biodiversity be calculated?
Using simpson’s index of diversity
Why is genetic biodiversity important?
Species that contain greater genetic biodiversity are likely to be able to adapt to changes in their environment, and hence are less likely to become extinct
What factors affect genetic biodiversity?
Mutations and interbreeding
What is gene flow?
When an individual migrates from one population and breed with a member of another population, causing alleles to be transferred between the two populations
What can cause decreases in genetic biodiversity?
Selective breeding, captive breeding, rare breeds, natural selection, artificial cloning, genetic bottlenecks, the founder effect, and genetic drift
What is selective breeding?
When only a few individuals within a population are selected for their advantageous characteristics and bred
What is captive breeding?
When only a small number of captive individuals of a species are available for breeding
What are rare breeds?
Situations where selective breeding has been used historically to produce a breed of animal or plant with attributes that then become less popular, so the numbers of the breed fall sharply
What are genetic bottlenecks?
When few individuals within a population survive an event or change, reducing the gene pool
What is the founder effect?
When a small number of individuals create a new colony, geographically isolated from the original
What is genetic drift?
The variance in allele frequency between generation due to the random nature of alleles being passed down to their offspring
What are polymorphic genes?
Genes that have more than one allele
How does proportion of polymorphic gene loci relate to genetic biodiversity?
Higher proportion, higher genetic biodiversity
What are the main ways that humans are decreasing biodiversity?
- Deforestation
- Agriculture
- Climate change
How does deforestation affect biodiversity?
- Directly reduces the number of trees present in an area
- Destroys habitats
- Forces animals to migrate
How does agriculture affect biodiversity?
- Deforestation
- Removal of hedgerows
- Use of chemicals such as pesticides and herbicides
- Monoculture
How does climate change affect biodiversity?
- Melting of the polar ice caps could lead to the extinction of the few plant and animal species living in these regions
- Rising sea levels from melting ice caps and thermal expansion of oceans could flood low-lying land
- Higher temperatures and less rainfall would result in some plant species failing to survive
- Insect life cycles and populations will change as they adapt to climate change
What are the aesthetic reasons for maintaining biodiversity?
- Presence of different plants and animals in our environment enriches our lives.
- Natural world provides inspiration for people
- Patients recover faster from stress and injury when supported by plants
What are the economic reasons for maintaining biodiversity?
Crops and agriculture are vital sources of food and income for many countries. Also, resources can be obtained, such as raw materials and medicines, from plants
What are the ecological reasons for maintaining biodiversity?
All organisms are interdependent on others for their survival. The removal of one species have a significant effect on others. Also, some species play a key role in maintaining the structure of an ecological community. These are keystone species.
What is conservation?
Active management of the environment and of natural resources.
What are the two main types of conversation?
In situ conservation - within the natural habitat.
Ex situ conservation - out of the natural habitat
What is sustainable development?
Economic development that needs of people today, without limiting the ability of future generations to meet their needs.
Give examples of in situ conversation strategies
- Controlled grazing
- Restricting human access
- Controlling poaching
- Feeding animals
- Reintroducing species
- Culling or removing invasive species
- Halting succession
Give examples of ex situ conservation strategies
Botanic gardens, seed banks, captive breeding
