biodiversity Flashcards
(25 cards)
What are the different kinds of biodiversity?
1 - Habitat diversity - The number of habitats.
2 - Species diversity - The number of species and the number of individuals in each species.
3 - Genetic diversity - The variation in alleles within a population of a species.
What is the meaning of species richness?
Species richness: The total number of different species in a habitat. A higher species richness indicates greater diversity.
What is the meaning of species eveness
Species evenness: A comparison of the numbers of individuals of each species in a community. More even abundances mean higher species evenness and diversity.
How is random sampling performed?
How random sampling works:
1 - Choose an area.
2 - Randomly generate coordinates across the area - This prevents sampling bias by removing human involvement in choosing samples.
3 - Collect samples from random coordinates - This gives us samples that are representative of the population.
4 - Repeat this several times - This gives us a large sample size and minimises the effects of chance.
5 - Analyse the data collected - This lets us identify any relationships.
What are the different methods of random sampling?
Techniques for sampling animals:
1 - Pooter - This samples small insects by sucking air containing the insects into a plastic container via a tube.
2 - Sweep net - This samples insects in long grass or air, where the net is swept in a ‘figure of eight’ motion.
3 - Pitfall trap - This samples small, ground-crawling animals like insects and spiders by catching them in a hidden trap.
4 - Tree beating - This samples the invertebrates living in a tree or bush by shaking or beating the tree to dislodge insects onto a white sheet below.
5 - Kick sampling - This samples river organisms by kicking a river bank and catching organisms downstream in a net.
6 - Quadrats - Frame quadrat - This is a square frame divided into a grid. The type and number of species within each section of the quadrat is recorded.m Point quadrat - This is a frame with a horizontal bar, through which pins are pushed at set intervals to touch the ground. Each species the pin touches is recorded.
What are the different types non random sampling?
Stratified
Opportunistic
Systematic
What is strartified sampling?
This divides the population into subgroups (strata) based on a characteristic.
A random sample is taken from each subgroup/stratum.
The number of samples taken in each stratum is proportional to the size of the stratum.
What is systematic sampling?
This samples different areas in a habitat separately at regular intervals to avoid bias.
What is opportunistic sampling?
This uses conveniently available organisms. It may not be representative of the population.
How can we measure genetic diversity?
Genetic biodiversity can be assessed by calculating the percentage of gene variants (alleles) in a genome within isolated populations. A high genetic biodiversity means there is a large variety of alleles in the population’s gene pool. This increases a population’s ability to adapt to environmental changes, and so helps them avoid extinction.
Equation = proportion of polymorphic gene loci = number of polymorphic loci/ total number of loci.
How can genetic diversity be decreased ?
Genetic biodiversity of a population can be decreased by:
1 - Selective breeding - Humans choose organisms with advantageous characteristics to breed (e.g. for rare dog breeds).
2 - Captive breeding programmes - A small group of individuals are bred in captivity.
3 - Artificial cloning - Using asexual reproduction to artificially produce large numbers of a particular (e.g. cloning crop plants).
4 - Natural selection - Species evolve and advantageous characteristics increase in a population.
5 - Genetic bottlenecks - A sudden decrease in population size means only a few individuals remain.
How can genetic diversity be increasesd?
Genetic biodiversity of a population can be increased by:
1 - Gene flow - This is interbreeding between different populations, introducing new alleles.
2 - Mutations in the DNA of an organism - This creates new alleles.
How does agriculture reduce biodiversity?
1 - Monocultures - This involves growing single crops over large areas, typically without crop rotation, directly decreasing the diversity of plants and of species that depend on them for food or a habitat. Monocultures also deplete the nutrients from soil.
2 - Converting woodland and hedgerows into fields - This decreases numbers of trees and other species, and destroys habitats relied on by many species.
3 - Filling in ponds, draining marshes, over-grazing of land - This directly destroys habitats and reduces species diversity.
4 - Removing weeds with herbicides - This may harm other species or those that depend on target species.
5 - Using pesticides to kill crop pests - This may harm other species or those that depend on target species.
6 - Using inorganic fertilisers - These may runoff into water courses, causing issues for aquatic species.
How does climate change reduce biodiversity?
Effects of climate change on biodiversity:
1 - Different regions experience changes in temperature and rainfall, and most species are adapted to specific climates.
2 - Changed conditions will make certain areas more or less habitable in general.
3 - Suitable habitats for some species will expand or contract e.g. melting polar ice caps removes a habitat for all polar animals.
4 - Changing climate conditions may influence species distribution and migration.
5 - Slow-moving species may become extinct if change is too rapid or severe.
6 - If conditions in general become warmer, tropical diseases will be more likely to spread.
7 - Rising sea levels may lead to more frequent flooding of terrestrial habitats in low-lying land.
how does human population reduce/ affect biodiversity?
Some impacts of the growing human population on biodiversity include:
1 - Deforestation for development destroys habitats and reduces ecosystem diversity.
2 - Overuse of resources causes certain species to decline or go extinct, reducing genetic and species diversity.
3 - Urban sprawl isolates wildlife populations, limiting breeding and decreasing genetic diversity.
4 - Pollution kills species directly and harms habitats long term.
What are the ecological reasons for maintain biodiversity?
Ecological reasons for conserving biodiversity:
1 - Food webs rely on multiple species, so declines in certain species can disrupt food chains.
2 - Losing keystone species that have disproportionately large effects on their environments destabilises these ecosystems.
3 - Nutrient cycles depend on decomposers recycling matter like carbon, nitrogen, sulfur, and phosphorous through ecosystems.
4 - Provides resilience to a changing climate, other abiotic stresses, and disease.
What are the economic reasons for maintaining biodiversity?
Some products that diverse ecosystems directly provided to the economy include:
1 - Renewable energy and fuel source production.
2 - Industry and raw material compounds like timber, fabric, latex, biofuels, and pesticides.
3 - Many medicines (like aspirin or morphine) originate from living organisms.
4 - Wildlife and natural scenery is a source of income for many countries through tourism (ecotourism).
5 - Microorganisms are the source of many useful products, including antibiotics.
Protecting genetic diversity supports future industries and the economy by providing:
1- Gene sources for future medicines and products that have not yet been discovered.
2 - Resilience against a changing climate, other abiotic stresses, and disease to economically useful organisms.
What are the asthetic reasons for biodiversity?
These include:
1 - Enriching our environment and providing inspiration for musicians, artists, photographers, poets, and writers.
2 - Helping people recover from stress and injury.
What is in situ conservation?
In situ conservation protects species in their natural habitats.
What is ex situ conservation?
Ex situ conservation relocates species facing imminent threat.
What are the methods and advanatge/disadvantage of in situ conservation?
Some methods of in situ conservation include:
1 - National parks and wildlife reserves.
2 - Controlling invasive or threatening species.
3 - Protecting food sources and nesting sites.
4 - Making hunting of certain species illegal.
5 - Marine conservation zones.
Advantages of in situ conservation include:
1 - Larger populations can be sustained.
2 - More chance of recovery than ex situ conservation.
Disadvantage:
But species remain at risk from things like climate change.
What are the methods and advanatge/disadvantage of ex situ conservation?
Some methods of ex situ conservation include:
1 - Relocating species to safer regions.
2 - Relocating species for captive breeding, research, and to education centres like zoos or botanic gardens.
3 - Storing seeds in seed banks.
4 - Reintroducing species once populations are stable.
Captive animals may struggle to survive when reintroduced into the wild because of potential loss of resistance to local diseases, behavioural issues, genetic differences, and limited suitable habitat.
What is the Rio Convention on Biological Diversity?
1 - Aims to develop conservation strategies and sustainable use of resources.
2 - Made biodiversity conservation an international legal responsibility.
3 - Aims to stabilise greenhouse gas concentrations, and prevent the transformation of fertile land into desert.
4 - Provides governments guidance on protecting habitats.
What is CITES?
1 - Makes trading endangered species internationally illegal.
2 - Regulates trade of wild plant and animals and their products (like furs, skins, and ivory) through licensing requirements.
3 - Raises awareness through education on threats.
