Biodiversity

What are the 3 levels that biodiversity can be assessed?

number & range of different ecosystems and habitats (habitat biodiversity), number of species and their relative abundance (species biodiversity), genetic variation of alleles and genes within each species (genetic biodiversity)

What is species richness?

number of species within an ecosystem

What is species eveness?

evenness of abundance across the different species present

How is genetic diversity measured?

proportion of genes that have more than one form (allele) and how many possible alleles each gene has

Why is genetic diversity limited in small populations?

Inbreeding in small populations leads to a high proportion of individuals being homozygous (e.g. AA to aa) for many genes, resulting in lower genetic diversity

Which factors decrease genetic biodiversity?

Selective breeding, artificial cloning, natural selection, genetic bottlenecks, founder effect, genetic drift

Which factors increase genetic biodiversity?

Mutations, gene flow

How do mutations increase genetic biodiversity?

Mutations in the DNA will create new alleles.

How does gene flow increase genetic biodiversity?

Interbreeding between populations allows for alleles to be transferred between the two populations

How does selective breeding decrease genetic biodiversity?

Only a few individuals within a population are bred due to their advantageous characteristics.

How does artificial cloning decrease genetic biodiversity?

Choosing an individual in a population to clone based on advantageous characteristics

How does natural selection decrease genetic biodiversity?

Alleles coding for less advantageous characteristics will be lost over time, resulting in species evolving to contain primarily advantageous alleles

How does genetic bottlenecks decrease genetic biodiversity?

Few individuals in a population survive an event/change meaning that only the alleles from surviving individuals can be passed on.

How does the flounder effect decrease genetic biodiversity?

A few individuals create a geographically isolated new colony, reducing the gene pool size

How does genetic drift decrease genetic biodiversity?

Due to the random nature of alleles being passed on, the frequency of their occurrence will vary so the existence of an allele can disappear from a population altogether

What is a locus?

particular location on a chromosome or the DNA at that position

What is polymorphic gene?

When more than one allel exists for a locus

What is the gene pool?

all the alleles of all the genes within a species

What is the equation for measuring genetic biodiversity?

Proportion of polymorphic gene loci = number of polymorphic gene loci / total number of loci

What is common in small, isolated populations?

Genetic diseases caused by recessive alleles can become more common

What is sampling used for?

Used to make an estimate of biodiversity in area by measuring biodiversity in multiple small areas within a habitat and using this information to represent the habitat as a whole

Why is sampling needed?

Measuring biodiversity within an ecosystem can be challenging; in large and complex ecosystems where it is impossible to find, identify and count every organism

What are the two things sampling measures?

Distribution and abundance

What is distrbution?

where organisms live within a habitat

What is abundance?

how many organisms are present

What does a sample have to be in order to be truly representative?

must be large enough to eliminate the effects of chance

What are the two types of sampling methods?

Random & non-random

What is random sampling?

The sampling sites are selected at random avoiding bias from the researcher choosing sites to assess

Methods of random sampling:

grid system, random number generator, graph coordinates

How is grid system used as method of random sampling?

set up by laying out two long tape measures along the outer edges of a habitat

How is graph coordiantes used as a method of random sampling?

numbers are used like graph coordinates, and the sample site is placed at the point of intersection

When is random sampling the best option of sampling?

When a sampling area is reasonably uniform or has no clear pattern of species distribution

What are the 3 main types of non-random sampling?

opportunistic, stratified, systematic

What is opportunistic sampling?

Sampling is carried out on the basis of opportunity (Eg: sample sites that can be reached quickly and safely are chosen)

What is stratified sampling?

number of random samples taken within each habitat type is proportional to the area covered by each habitat type

What is systematic sampling?

Samples are taken across a habitat with reference to the changes in habitat conditions (Eg increasing altitude, increasing distance from the edge of a woodland, increasing distance from the shore line)

What is reliability?

The degree to which an investigation produces stable and consistent results

How can sampling bias be reduced?

Random sampling using quadrats in selected areas, random selection of transects, systematic sampling of transects as regular intervals

What is the risk of chance during sampling?

organisms selected may by chance not be representative of the entire population

How can chance be reduced?

using a large sample size

Different methods of sampling for ANIMALS:

Pooter, sweep nets, pitfall traps, tree beating, kick sampling

What are sweeping nets & what do they do?

Large, strong nets that is swept across vegetation to catch flying insects and insects living on leaves, after sampling count insects and identify

What are pitfall traps & what do they do?

cans or jars that are sunk into ground so ground dwelling invertebrates fall into trap and lid ensures trap doesn’t fill with rainwater

What are pooters & what do they do?

small plastic / glass containers with two tubes from the lid which is used to suck up small invertebrates by one tube placing over the insect and the 2nd tube used to suction

Different method of sampling for PLANTS:

Quadrats & transects

What are the two types of quadrats?

Point & frame quadrat

What can be measured in a quadrat?

number of species present, number of individuals of species present, presence of species, percentage cover of species

What does a transect measure?

abundance and distribution of organisms is affected by changes in abiotic factors across a habitat

What are the two types of transect?

line (identity organisms touching the line) and belt transect (identify organisms present in area between two parallel lines by recording abundance or % cover of each species within each quadrat)

List abiotic factors, sensors used for each and units:

wind speed (anemometer, m s^-1), light intensity (light meter, lx), humidity (humidity sensor, mg dm^-3), pH (pH probe, pH). temperature (Temperature probe, degrees celcius), O2 content in water (dissolved oxygen probe, mg dm^-3)

What is the formula for simpson’s index?

D = 1 - Sum of ( n / N) ² where n is the total number of organisms for a single species and N is the total number of organisms for ALL species

How od you calculate simpson’s index?

• Step 1: First calculate n / N for each species

• Step 2: Square each of these values

• Step 3: Add them together and subtract the total from

If D is near to 0 what does it mean?

Low levels of biodiversity

If D is near 1 what does it mean?

High levels of biodiversity

What are the reasons for exponential growth?

Improved technology leading to abundance of food increasing birth rate, improved medicine / hygiene / health care decreasing death rate

How does growth of human population affect biodiversity?

As human population increases and countries become more economically developed, requirement for resources increases

What are the main factors affecting biodiversity?

Habitat destruction, overexploitation, agriculture, climate change

What are the consequences of habitat destruction?

Habitat loss (plants and animals lose their habitats) & habitat fragmentation (habitats are divided into small areas so populations living within these separated habitat fragments are more likely to suffer from inbreeding or local extinction)

Give examples of habitat destruction?

Deforestation, destroying marine habitats (Eg coral reefs as dynamite is used to catch fish damaging coral, sea beds as trawling results in nets being dragged along sea bed)

What is overexploitation?

natural resources being used faster than they can be replaced

Give examples of overexploitation?

• Deforestation is unsustainable as trees are removed but not replaced

• Overexploitated fish stocks affecting those feeding on fish

  • Hunting as wild, non-farmed species hunted and removed more quickly than their populations can be replendished

Name modern farming practices:

• Farms became more specialised so they grew only one crop or raised one type of livestock (monoculture)

• There was a switch to growing cereal crops rather than vegetables

• Fields were made bigger to accommodate machinery via the removal of hedgerows and stonewalls

• More land was made suitable by draining wetland and filling in ponds

• The use of fertilisers and pesticides massively increased

Why do MONOCULTURES have a negative impact on biodiversity?

support much lower levels of biodiversity compared to natural habitats or even natural grazing land

How do HEDGEROWS negatively impact biodiversity?

As hedgerows are being increasingly removed, this habitat and the biodiversity it supports for insects / mammals / birds is lost

How do FERTILISERS negatively affect biodiversity?

Fertilisers can leach into waterways, causing eutrophication, which can lead to the death of many aquatic invertebrate and fish species

How do PESTICIDES negatively affect biodiversity?

used on crops kill insect pests but also kill many non-target species such as important insect pollinators like bees

What are the consequences of climate change?

Causing weather patterns to change and the frequency of extreme weather events, (such as hurricanes, typhoons, floods and droughts, to increase) so species can’t adapat to these fast changes

Negative effects of global warming:

Causes many species to move towards the poles or to higher altitudes but these species may not be able to compete with, or may even out-compete, the species already present in these habitats, with either result leading to decreased biodiversity

Effect of global warming on plant species:

Plant species may not be able to move or change their distributions fast enough to adapt to increasing temperature and may go extinct as a result

How does global warming affect marine biodiversity?

Ocean acidification & Coral bleaching

What is ocean acidification?

Increasing atmospheric CO₂ dissolving in seawater, decreasing its pH which is negatively affecting organisms that require calcium carbonate for shells (e.g. plankton and coral polyps)

What s coral bleaching?

Increased ocean temperatures have led to increased frequency of coral-bleaching, where the tiny organisms that live inside corals and help keep them alive leave due to temperature stress so the corals die and are broken down, eventually leading to the loss of whole coral reefs

Why has the bumblebee population decreased rapidly?

Bumblebees require habitats with a large number of flowering plants to ensure a supply of pollen and nectar all year round but extensive farming (decrease plant biodiversity) and use of pesticides negatively effect bees

What are the 2 factors making farming economically viable?

high yield and profit

Why is ethical sustainable farming practices less used?

Expensive, labour intensive, time-intensive and reduce yield of crops and livestock

What are the reasons for maintaining biodiversity?

ecological, economical, aesthetic

What are keystone species?

species that have a large impact on the ecoysystem so the lack of their species has knock on effects

What are the environmental / ecological reasons for maintaining biodiversity?

protect keystone species to ensure interdependence of organisms, genetic resources and services such as

• plants absorbing CO2 to reduce greenhouse effect

• microorganisms digest and break down organic waste

• water cycle needed for drinking water

• fungi and bacteria part of nutrient cycle

• plants are producers so are a direct and indirect energy source for humans

Why do ecosystems have a lot of economic value?

many medicines originate from plant / fungi / bacteria, ecotourism is a major source of income for countries, need to reduce soil depletion to allow continuous monoculture, ecosystems made contributions to science and technology (Eg enzymes in DNA sequencing found in bacteria in ecosystem)

What are the aesthetic reasons for maintaining bioidversity?

It is believed to maintain biodiversity to protect the landscape because of aesthetic benefits

What is in situ conservation?

when a species is kept in their natural habitat for conservation as their support systems already exist there

Give examples of in situ conservation:

marine conservation zones, national parks, controlling poaching,

What are the benefits of in situ conservation?

Maintains genetic biodiversity, Maintains evolutionary adaptations, Preserves interdependent relationships

What are the restrictions for national parks?

• Humans access is strictly controlled

• Industrial activities such as agriculture and building are tightly regulated

• Hunting is limited or completely prohibited

What are the restrictions for marine parks?

restrictions to prevent overfishing and pollution

Why is public engagement important for conservation?

• national parks attract tourists which increases money and awareness

• local community can be involved with national parks so provides jobs

• profits from park can be used to improve health and education standards in nearby communities

What is ex situ conservation?

conservation outside of a species’ natural habitat in captivity

Give examples of ex situ conservation:

seed banks, botanic gardens, zoos, frozen zoos

What is the purpose of the captive breeding programmes?

To breed individuals of a species so their offspring can be released into the wild

What are the problems with zoos?

• Captive breeding of small species populations can reduce genetic diversity

• Certain animal species will not breed in captivity

• Not all zoos can provide adequate habitats for animals with specific needs

What are botanic gardens?

plant zoos which use cuttings and seeds collected from the wild to establish a population of the endangered species in captivity

What are frozen zoos?

stores genetic materials of endangered species of animals at low temperatures so can be kept for a long time

What is a seed bank?

facility that conserves plant diversity by drying and storing seeds in a temperature controlled environment

How is the gene pool maintained in seed banks?

seds of the same species are collected from different sites to maintain gene pool

What methods are used for seeds that can’t be frozen?

successive generations must be grown or tissue cultures taken

What does CITES stand for?

Convention on International Trade in Endangered Species of Wild Flora and Fauna

What is CITES?

global agreement to control the trade of endangered species and their associated products

What does CBD stand for?

Rio Convention on Biological Diversity

What did the Convention of Biological diversity attempt to do?

countries signed convention to design and implement national strategies for conservation use of biodiversity and organise international cooperation

What does CSS stand for?

Countryside Stewardship Scheme