Chapter 11 - Biodiversity Flashcards
What are the 3 types of biodiversity?
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
What is habitat biodiversity?
The number of different habitats found within a particular area
What are the two types of species biodiversity?
Species richness
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 a species living in a particular area
What is genetic biodiversity?
The variety of genes that make up a species
What is the advantage of a greater genetic biodiversity?
More likely to have better adaptions for new/different selection pressures (e.g. the introduction of a new disease, species with higher genetic biodiversity are more likely to be resistant)
What is sampling?
Taking measurements of a limited number of individuals present in a particular order
What is random sampling?
Selecting individuals by complete chance, in which each individual in the population has an equal likelihood of selection
What are the 3 types of non-random sampling?
Opportunistic
Stratified
Systematic
What is opportunistic sampling?
When you select organisms that are conveniently available
What is stratified sampling?
When a population is divided into different sub-groups (strata), and then a random sample is taken from these strata
What is systematic sampling?
When samples are taken at specified and periodic points in a specific area
Example of systematic sampling
Taking samples of rock along a beach, every metre along a transect
What 2 factors that decrease reliability of results?
- Sampling bias
- Chance (outliers)
What is a pooter used for?
Catching small insects
What is a sweep net used for?
Catching insects in areas of long grass
What is a pitfall trap used for?
Catching small, crawling invertebrates (e.g. beetles, spiders and slugs)
What is tree beating used for?
Catching invertebrates in a tree
What is kick sampling used for?
Catching organisms living in a river
What are plants usually sampled using?
A quadrat
What are the two types of quadrat?
Point quadrat
Frame quadrat
What is a point quadrat?
A frame containing a horizontal bar, in which at set intervals along the bar, a pin can be pushed through to reach the ground. Each species of plant the pin touches is recorded
What is a frame quadrat?
A square frame divided into a grid of equal sections
What are the 3 things you measure using a quadrat?
Density
Percentage cover
Frequency
How do you measure density using a quadrat?
Count the number of a given plant/s in a 1x1; this will then give you density per square metre
How do you measure frequency using a quadrat?
Count the number of squares in which a given species is present. For example if a plant was present in 65 of 100 squares, it would give the plant a percentage of occurrence of 65%
How do you measure percentage cover using a quadrat?
Estimate (by eye) the percentage within a quadrat a given species covers
What is the main technique to determine population size over a large area?
Capture-mark-release-recapture
What are abiotic factors?
Non-living conditions in a habitat (e.g. temperature)
What do you use to measure wind speed?
Anemometer
What do you use to measure light intensity?
Light meter
What do you use to measure humidity?
Humidity sensor
What do you use to measure pH?
pH probe
What do you use to measure temperature?
Temperature probe
What do you use to measure oxygen content in water?
Dissolved oxygen probe
What is a calculation to measure biodiversity?
Simpson’s Index of Diversity
What 2 things do you need to calculate Simpson’s Index of Biodiversity?
The total number of organisms of all species
The total number of organisms of a particular species (for each species)
Why is Simpson’s Index a good way of measuring biodiversity?
It takes both species evenness and richness into account
What factors increase genetic biodiversity?
- Genetic mutations
- Gene flow
What is gene flow?
When an individual from one population breeds with an individual from a different population, so alleles/DNA are transferred between the two populations
What is selective breeding?
Where only a few individuals within a population are selected to be bred due to their advantageous characteristics- this decreases genetic biodiversity
What are captive breeding programs?
Where only a small number of captive individuals are available for breeding- this means there is a small gene pool so low genetic biodiversity
How does natural selection affect genetic biodiversity?
During natural selection, alleles for less advantageous characteristics will be eventually lost from a population- this therefore leads to a reduction in genetic biodiversity
What is genetic drift and give an example of it?
When the frequency of alleles changes as a result of a random occurrence.
For example, a meteor could hit a random area of a population and reduce the frequency of certain alleles from the population of a species in a unequal way
What is polymorphism/polymorphic genes?
Genes with more than one possible allele
How do you calculate the proportion of genes that are polymorphic?
Proportion of polymorphic gene species = number of polymorphic gene species/total number of species
How does deforestation affect biodiversity?
- Felling specific types of trees but leaving others reduces the biodiversity of trees in that area
- Destroys the habitat of many species, causing many to reduce in number, and also forcing many to other areas. These both have a knock-on effect on the balance of the food web, which will result in a decrease in biodiversity
What are the 3 main human causes of reduced biodiversity?
- Deforestation
- Climate change
- Agriculture
3 ways in which agriculture affects biodiversity
- Deforestation
- Monoculture
- Pesticides + herbicides
What is monoculture and how does it affect biodiversity?
Where a large area of land is used for the growth of a single crop- this therefore reduces the biodiversity of that area
How do pesticides and herbicides affect biodiversity?
They kill pests/weeds that would otherwise be growing in that area, reducing biodiversity
3 ways in which climate change affects biodiversity
- Ice caps melting = loss of polar habitats
- Sea levels rising = flooding = loss of habitat
- Higher temperatures = harder to survive for certain organisms
What are the 3 broad categories of the importance of maintaining biodiversity?
- Aesthetic
- Economic
- Ecological
Aesthetic reasons for maintaining biodiversity:
- Presence of plants and animals enriches our lives, such as through reducing stress
- Natural world is often inspiration for people such as artists and writers, which in turn provide pleasure for us
Economic reasons for maintaining biodiversity:
- Maintain soil fertility = countries are able to continue to cultivate their own crops
- Non-sustainable harvesting = eventual loss of that resource = collapse of the industry
- Lack of (genetic) biodiversity = easier to get wiped out by certain selection pressures = widespread famine (e.g. Irish potato famine, which resulted in 1 million deaths)
- Biodiverse areas attract tourism
Ecological reasons for maintaining biodiversity:
Organisms are interdependent on one another for their survival, meaning if certain species are affected, this often has a knock-on effect upon the entire food web
What are keystone species?
Species within a community that have a disproportionately large impact in an ecosystem (relative to their abundance). If a keystone species is removed, the ecosystem is often drastically changed
Why are keystone species often predators?
As just a few predators can control the distribution and population of large numbers of prey species, preventing one species from becoming too dominant
What is conservation?
The preservation and management of the environment and of natural resources
What are the two main ways conservation is divided?
In situ conservation
Ex situ conservation
What is in situ conservation?
Conservation that takes place within the natural habitat of the organism
What is ex situ conservation?
Conservation that takes place outside of the natural habitat of the organism
What are the 4 classifications of species that may need conservation?
- Extinct
- Extinct in the wild
- Endangered
- Vulnerable
What does extinct mean?
There are no organisms of the species in the entire world
What does extinct in the wild mean?
Organisms of the species are only present in captivity
What does endangered mean?
A species in danger of extinction
What does vulnerable mean?
A species that is considered likely to become endangered in the near future
What is sustainable development?
Economic development that meets the demand of people today, without limiting the ability of future generations to meet their need
Why is in situ often better than ex situ conservation?
Allows interdependent relationships to be maintained
Allows the species to continue to adapt to their environment
Often cheaper
What are examples of areas of in situ conservation?
- Wildlife reserves
- Marine conservation zones
How is poaching controlled?
Issuing fines/arresting poachers
Removal of desired product for poachers (e.g. removing rhino horn)
Banning access
What is succession?
The natural process in which early colonising species are replaced over time, until a stable population is achieved- this can cause certain species to become extinct
Give 2 in situ conservation techniques used
Controlling/culling of invasive species
Feeding the given species
What are examples of ex situ institutions?
- Botanic gardens
- Gene banks
- Captive breeding programs
What do gene banks do?
They freeze genetic material, preserving the genes of many species of both animal and plant
What do captive breeding programs do?
They produce offspring of species in a human controlled environment- they aim to create a healthy population size of a species, then reintroduce it into the wild
Why may species born in captivity not be suitable for release?
- Not resistant to local diseases
- Behaviour necessary to survive not learnt
- Destroyed habitat
