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Dr Bhavsar's A level Biology > Biodiversity essential notes > Flashcards

Biodiversity essential notes Flashcards

1
Q

State the types of biodiversity

A
  1. Habitat biodiversity 2. Species biodiversity 3. Genetic biodiversity
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2
Q

Discuss what habitat biodiversity means

A
  1. Habitat diversity refers to the number of environments on in which life exists
  2. Each habitat contains the organisms adapted to survive there
  3. The greater the habitat diversity, the greater the biodiversity overall
  4. Sand dunes, woodland, meadows and streams are examples of different environmental conditions, allowing the survival of differently adapted organisms
  5. Maintaining different habitats allows the great diversity in the types of species we have to be maintained
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3
Q

Discuss what species biodiversity means

A
  1. Species diversity refers to the variety of organisms in a habitat
  2. It is made up of species richness and species evenness
  3. Species richness refers to the number of different species in a habitat
  4. Species evenness compares the proportions of the community made up by the different species
  5. Having high species diversity maintains functioning ecosystems, and provides us with sustainable and valuable resources
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4
Q

Discuss what genetic biodiversity means

A
  1. Genetic diversity is a measure of the variety that exists within the species
  2. It is measured by the number of genes present in the species (including all the different alleles)
  3. Having high genetic variation in a species increases the chances of the species adapting to environmental changes (less likely to become extinct)
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5
Q

Explain why sampling is necessary

A
  1. It is important to quantify biodiversity to measure the possible impact of development, or conservation efforts
  2. But counting every organism in a large area is impractical
  3. Smaller areas of a habitat are therefore sampled
  4. In a way that is representative
  5. The data are used to make an estimate for the larger area
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6
Q

Describe the principles of random sampling

A
  1. Random sampling means the investigator does not select which areas or individuals will be sampled
  2. This is a way that samples are made more representative and avoid bias
  3. Random sampling is used when a two-dimensional area is being sampled, for example, with quadrats
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7
Q

Describe the types of non-random sampling

A
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8
Q

Describe how sampling can be made more reliable and representative

A
  1. Removing as much bias as possible. For example, using random or systematic sampling
  2. Accounting for daily and seasonal changes
  3. Reducing the element of chance, by taking large sample sizes or repeat measurements
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9
Q

Describe how you would use quadrats to estimate plant biodiversity in an area

A
  1. Used to measure the biodiversity in a two-dimensional area
  2. Often to compare and find the difference between two areas
  3. Choose an area and decide on a representative number of samples
  4. Arrange tape measures like x-y axes of a grid
  5. Use a calculator to generate random numbers as coordinates
  6. Place quadrats at determined coordinates and
    1. Record species richness by identifying species present using an identification key
    2. Record abundance of each species by estimation
  7. Use species richness and evenness to determine biodiversity
  8. Analysed with a t-test
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10
Q

Describe how you would use transects to investigate plant biodiversity

A
  1. Used to investigate the effect of a changing factor (such soil pH, moisture) over a particular linear distance
  2. Decide on the distance for the transect
  3. Place quadrat or point frame at regular intervals (systematic sampling) along the transect
  4. For each quadrat record:
    1. The factor being investigated
    2. Any control variables
    3. Species present using identification key
    4. and estimate species abundance
  5. Biodiversity at at each point in the transect can be calculated
  6. Parallel transects can be used to repeat the investigation
  7. Analysed with a Spearman rank correlation test
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11
Q

Describe the ways in which plant abundance can be measured

A
  1. Measuring actual density: if the individual plants are easy to count, record the number per the area of the quadrat
  2. Percentage cover (frequency): using the number of grid squares the plant is present in to estimate a percentage
  3. In a point frame, each species that touching each of the pins is recorded
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12
Q

Describe the techniques that are appropriate for measuring animal abundance

A
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13
Q

Describe how estimates of animal abundances can be made from sample collection

A
  1. Large insects and small mammals that have been captured
  2. Are marked (in a way that doesn’t cause harm) (C1)
  3. They are then released, and traps are set again.
  4. Some individuals are trapped again (C2)
  5. The numbers of marked individuals captured again (C3), is used to estimate the total wild population
  6. Using the equation Total population = (C1 x C2)/C3
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14
Q

Describe how species richness and evenness can be used to determine the biodiversity of an area

A
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15
Q

Describe the significance of a low Biodiversity index

A
  1. Few successful (dominant) species in the ecosystem
  2. Stressful or extreme environmental conditions, few niches
  3. Few species make up the ecosystem, but with very specific adaptations
  4. Simple food webs (look more like food chains)
  5. Changes to the environment (human impact, climate change, new disease or predator) have a big impact on the ecosystem and could result in population eradication
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16
Q

Describe the significance of a high Biodiversity index

A
  1. High number of species in the ecosystem have large population (no single dominating species)
  2. Less extreme conditions, more available niches for species to survive
  3. Many species successful in the habitat, with fewer specific adaptations required
  4. Complex food webs exist (each species has food options)
  5. Ecosystems are more resilient to changes in the environment (human impact, climate change, new disease or predator)
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17
Q

State the significance of genetic biodiversity

A
  1. Genetic diversity refers to all the alleles present in a population
  2. The more alleles present, the more chance that there are alleles that allow survival when environmental conditions change
  3. This allows members of the population or species to continue to survive and reproduce
  4. Such populations are more adaptable, and less vulnerable to extinction
  5. The opposite is true for populations with low genetic biodiversity
18
Q

Describe the factors that can increase genetic biodiversity

A
  1. Mutation is a process that creates new alleles
  2. Interbreeding between distinct populations allows new alleles to enter a population
19
Q

Describe the factors that can reduce genetic biodiversity

A
  1. Selective breeding
  2. Captive breeding programmes
  3. Use of artificial cloning over traditional propagation methods
  4. Natural selection
  5. Genetic bottlenecks
  6. Founder effect
  7. Genetic drift
20
Q

Describe how genetic biodiversity can be measured

A
  1. When a particular gene locus has two versions of a gene (ie when an individual is heterozygous), this is known as a polymorphism
  2. A population can be analysed for the proportion of gene positions that show polymorphism (heterozygosity)
  3. (this can be done by analysing the DNA of each member of the population by electrophoresis)
  4. The greater the proportion of genes that have multiple alleles, the greater the genetic biodiversity
  5. This is represented by the equation:
  6. Number of polymorphic gene loci/total gene loci
21
Q

State the (human influenced) factors that affect biodiversity

A
  1. Deforestation
  2. Agriculture
  3. Climate change
22
Q

Describe how deforestation reduces biodiversity

A
  1. Deforestation can be natural (eg forest fires) but is mostly due to human activity
  2. Human population growth means forests resources and space is required (homes, travel, building)
  3. Reduces tree abundance (reduces evenness)
  4. If a particular species is removed, it reduces species richness in the area
  5. Removes habitat for animal species so further reduces species richness
23
Q

Describe how agriculture reduces biodiversity

A
  1. As human population growth occurs, using large areas of land for food production is required: agriculture
  2. Agriculture may require deforestation to provide the space (see deforestation)
  3. Hedgerows which are habitats for animal species may be removed for increased space and allowing more mechanisation
  4. Use of chemicals such as herbicides and pesticides destroys certain plant and animal species as well as the food source for others reducing species richness
  5. Replacing wild habitat with only type of crop is a monoculture, and dramatically reduces species richness
  6. Furthermore, certain varieties of crops are preferentially grown, resulting in genetic variation reduction (genetic erosion)
24
Q

Describe how human activity may cause climate change

A
  1. The industrialisation required to maintain and develop lifestyles of the growing human population has resulted in activities that could affect the climate
  2. Combustion of fossil fuels increases atmospheric greenhouse gases
  3. These cause the temperature of the atmosphere to rise
  4. This changes the climatic conditions of habitats all over the Earth
25
Q

Describe how climate change can reduce biodiversity

A
  1. Communities of organisms have specific adaptations to survive in specific environmental conditions
  2. If their conditions change, their adaptations may not allow them to survive.
  3. They may be at risk of extinction or have to migrate to more suitable conditions
  4. Melting of polar ice caps reduce the habitat for many species adapted to survive there
  5. Rising sea levels may reduce terrestrial habitats
  6. Changing temperatures and rainfall will affect plant species. This will affect the rest of the ecosystem
  7. temperature-dependent insect development and behaviour may be affected, eg pollination carried out by bees
  8. As animal populations migrate, any pathogens they carry (concept of vectors) may get introduced to new areas
26
Q

State the main reasons for maintaining biodiversity

A
  1. Aesthetic
  2. Economic
  3. Ecological
27
Q

Describe the ecological reasons to maintain biodiversity

28
Q

Describe the aesthetic reasons to maintain biodiversity

A
  1. The variety of plants and animal life, including natural landscapes and ecosystems is valuable to our mental wellbeing (relaxation)
  2. Biological life provides inspiration for art
  3. Natural environments may speed up recovery from mental and physical injury
29
Q

Describe the economic reasons to maintain biodiversity

30
Q

State the categories and methods of conservation

31
Q

Describe the advantages of ex situ conservation

A
  1. Organisms are protected from predation and poaching
  2. Health of individuals can be monitored and medical treatment given
  3. Populations can be at different sites, so things affecting one population would affect entire species
  4. Genetic diversity of the population can be measured
  5. Selective breeding can be used to maintain genetic diversity
  6. In vitro techniques can improve reproductive success
  7. Population size of endangered animals and plants can be increased
  8. Reproductive physiology, ecology and behaviour can be researched
  9. Wildlife parks can generate funding for conservation activities
  10. Wildlife parks can be used for education
32
Q

Describe the disadvantages of ex situ conservation

A
  1. Captive populations (being smaller) have lower genetic diversity
  2. Being in enclosed spaces makes disease transmission and exposure to new pathogens more likely
  3. Organisms are not in their natural habitat, so may reduce their chances of survival (conditions don’s suit their adaptations)
  4. May be difficult to replicate diet, behaviour and reproduction
  5. Animals may find it difficult to survive (finding food, avoiding predation) in the wild after leaving the wildlife park
  6. They may not be accepted by wild members of the population
33
Q

Describe conservation carried out by wildlife reserves

A
  1. An area is designated as wildlife reserve, and may contain the following:
  2. Controlled grazing
  3. Restricting (not preventing) human access to maintain normal animal behaviours
  4. Controlling poaching
  5. Feeding animals (to increase population sizes)
  6. Reintroduction of species (from other habitats, or from ex situ programmes)
  7. Removal/control of invasive species
  8. Preventing ecological succession (maintaining the habitat)
34
Q

Describe conservation carried out by marine conservation zones

A
  1. A protected marine area, where:
  2. Fishing or other human activity is controlled
  3. To allow aquatic species populations to be restored
35
Q

Describe conservation carried out by botanic gardens

A
  1. Plant species are actively managed
  2. To provide the best conditions and nutrients for their growth
  3. Species grown in botanic gardens are protected from risks that may be present in their natural habitat
36
Q

Describe conservation carried out by seed banks

A
  1. Plants have a dormant stage in their lifecycle, seeds which are relatively easy to collect, store and use.
  2. Seeds are produced in large numbers, and can be collected without too much impact on the population (doesn’t reduce genetic diversity)
  3. Seeds are preserved at low temperature and low humidity
  4. This preserves wild varieties and the genetic biodiversity of the species (despite loss of biodiversity due to deforestation and monocultures)
  5. Seeds can be tested regularly to check for viability (and if new seeds need to be collected)
  6. Large numbers of seeds can be stored in a small space
  7. Many plants can reproduce asexually
  8. Plants grown ex situ can be
    1. Used for building materials
    2. Food crops as climate changes
    3. Reestablishment of habitats
37
Q

Describe conservation carried out by captive breeding programmes

A
  1. Zoos aim to maintain populations of endangered species
  2. They must get these organisms to reproduce in captive breeding programs
  3. They must do research on the habitats, mating behaviour and reproductive physiology of the species
  4. They must also have genetic information of each individual, to ensure that genetic variation of the species is maintained in the offspring
  5. Techniques such as artificial insemination, in-vitro fertilisation and cryogenic storage of embryos and gametes are used
  6. International cooperation may be needed to ensure that breeding pairs maintain the genetic diversity of population and species
38
Q

State the types conservation legislation and agreements

A
  1. Convention on international trade in endangered species (CITES)
  2. The Rio convention on biological diversity (CBD)
  3. The countryside stewardship scheme (CSS)
39
Q

Describe the key elements of CITES

A
  1. Regulates international trade of certain species of wild plants and animals and their products
  2. Requires international cooperation to prevent trade in these products
  3. If trade is minimised, the wild animals and plants would be exploited less, as there may be less financial incentive to do so
  4. And this would prevent their harm or removal from their natural habitats
40
Q

Describe the key elements of CBD

A
  1. The aim is international cooperation to develop sustainable use of natural resources
  2. That allows humans to benefit from natural resources while maintaining biodiversity
  3. This included agreements to control greenhouse gas concentrations in the atmosphere
  4. Preventing fertile land from undergoing soil erosion and desertification
  5. International cooperation is needed because many ecosystems cross national boundaries
41
Q

Describe the key elements of CSS

A
  1. Government made payments to local authorities and private landowners
  2. To invest in the preservation and restoration of the countryside. Its aims were:
  3. Improve the natural beauty and diversity of the countryside
  4. Enhance and restore targeted landscapes, wildlife habitats and historical features
  5. Improve opportunities for public access

Dr Bhavsar's A level Biology (9 decks)

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