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Biology AS > Biodiversity and Evolution > Flashcards

Biodiversity and Evolution Flashcards

1
Q

What is biodiversity? e.g. the different levels at which it can be considered and its different significances at each level - habitat, species, genetic.

A

the variability among living organisms and the habitats in which they live.
Within a habitat/ecosystem, biodiversity covers species richness and evenness as well as the range of physical conditions there.
Species biodiversity includes the variability of individuals, the range of form, size, colour - physical characteristcs, and differences in resistance to pests and diseases - physiological characteristics.
Genetic diversity describes the range of different genes in the species - larger population = more genetically varied

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2
Q

Define species

A

a group of individuals capable of interbreeding and producing fertile offspring

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3
Q

Define habitat

A

the place in which a species lives

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4
Q

How might the biodiversity of a habitat be measured

A

by sampling, to give an estimate of the number of species present, where they live and what they need. Useful to allow us to protect them and their environment.

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5
Q

How is random sampling used to measure the biodiversity of a habitat? - quadrats

A

Area is marked out a metre intervals on 2 sides. Co-ordinates are selected using a random number generator, and suitably sized frame quadrats are placed. Species are identified using dichotomous keys.
The results show species richness- no.of different species, and species evenness - relative abundance of species present which are used to calculate Simpson’s Index of Diversity. D = 1-(Σ(n/N)^2) where N is total organisms of all species and n is total no. of organisms of a particular species.

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6
Q

Outline the significance of both high and low values of Simpson’s Index of Diversity - why might they be low?

A

Higher number = greater diversity, lower number = less diversity, possibly due to a few dominant species that prevent others surviving in the same habitat.

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7
Q

what is classification?

A

the arrangement of organisms into groups

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8
Q

what is phylogeny and how does it relate to classification?

A

The study of the evolutionary relationships of organisms, allowing an evolutionary tree to be created showing the closeness of relationships between organisms by their common ancestors. It is a way to sort organisms into groups so is a means of classification.

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9
Q

describe the classification of species into the taxonomic hierarchy of taxa.

A

Organisms are grouped into a series of taxa: domain, kingdom, phylum, class, order, family, genus and species

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10
Q

Outline the binomial system of nomenclature

A

Tells you the genus - first name - and the species - second name. Genus is capitalises, species is not, and both are shown in italics. This is the scientific name and is the same world-wide. (e.g. Homo sapiens [in italics])

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11
Q

What were classification systems originally based on and how does this compare with more recent approaches?

A

Originally - physical characteristics and observable features
More recent thanks to new technology/discoveries etc:
- analysis of DNA structure e.g. base sequences
- molecular evidence e.g. protein and amino acid sequences
- cell structures

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12
Q

Describe the key characteristics of the Prokaryote kingdom? e.g?

A

e. g. bacteria
- no nucleus
- always have cell walls of muerin (aka peptidoglycan)
- no membrane-bound organelles
- loop of naked DNA
- 70s ribosomes
- exist as single cells/groups of cells

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13
Q

Describe the key characteristics of the Plantae kingdom? e.g?

A

e. g. plants, mosses, ferns, flowering plants
- eukaryotic cells with cellulose cell walls
- multicellular, with tissues and organs
- large, permanent sap vacuoles
- photosynthetic, with chloroplasts

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14
Q

Describe the key characteristics of the Animalia kingdom? e.g?

A

animals e.g. insects birds worms mammals

  • multicellular, with tissues and organs
  • eukaryotic cells with no cell walls
  • heterotrophic - no chloroplasts
  • no permanent vacuoles
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15
Q

Describe the key characteristics of the Fungi kingdom? e.g?

A

e. g. yeasts, moulds, mushrooms, toadstools
- eukaryotic cells
- cell walls made of chitin
- no chloroplasts - heterotrophic
- uni/multicellular, with chains of cells called hyphae
- reproduce by means of spores

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16
Q

Describe the key characteristics of the Protoctista kingdom? e.g?
n.b. the protoctista is not a phylogenetic group but was instead created to remove non-related species from the other kingdoms

A

amoeba (protozoan), seaweeds

  • simple eukaryotic organisms without tissues or organs
  • many unicellular, some with groups of cells
  • some animal-like cells: protozoans
  • some plant-like cells: algae
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17
Q

What are the key similarities differences between the 3 domain and 5 kingdom classification systems?

A

DIFFERENCES:
- 5 Kingdoms: 7 levels and 5 major groups (bacteria, archaea, eukarya). Based on structural differences between organisms.
- 3 domains: 8 possible levels, 3 major groups. Based more on molecular and biochemical differences.
SIMILARITIES:
- hierarchal systems
- based on similarities and differences between groups
- show possible evolutionary relationships

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18
Q

define the term intraspecific variation. What are the two causes of infraspecific variation?

A

differences between individuals of the same species. Can be genetic variation and environmental variation.

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19
Q

What are 3 sources of genetic variation?

A
  • random mutations (mistakes in DNA replication) producing new alleles
  • different alleles in each of the parents in sexually reproducing organisms
  • mixing of alleles during meiosis to produce varied gametes
  • random fertilisation of the varied gametes
20
Q

What are 3 sources of environmental variation?

A
  • exposure to sunlight causing tanning
  • diet differences causing variations in height and weight
  • light intensity affecting rate of photosynthesis and therefore height in plants
  • mineral availability e.g. nitrates for growth and therefore height in plants
21
Q

Why is environmental variation not important in evolution?

A

They do not affect the DNA so cannot be inherited

22
Q

Describe discontinuous variation and give 3 examples of a range of characteristics found in plants, animals and microorganisms

A

Where the characteristics are clear-cut with no intermediates. Usually due to 1 or 2 genes controlling the characteristics. e.g:
- A, B, AB and O blood groups in humans
- normal coloured or mutant albino animals/plant
- pest resistance in insects
- drug resistance in microorganisms
& many more

23
Q

Describe continuous variation and give 3 examples of such characteristics. State whether they are controlled by genes/environment/both.

A

When the characteristic shows a complete range and cannot be put into non-overlapping groups. Controlled by many genes, the environment, or both. Quantitative - has to be measured. Has a range of intermediate values.

e. g:
- height in humans (genes and environment)
- skin colour in humans (genes and environment)
- eye colour in humans (genes)
- length of leaves on one plant (environment)

24
Q

What are the four observations made by Darwin in proposing his theory of natural selection, and what 3 deductions did these lead him to make?

A
  1. all organisms over-reproduce
  2. population sizes remain fairly constant in the wild
  3. individuals within a species vary from each other
  4. some of these variations are inherited
    Deductions:
  5. There is competition for survival due to limited food, predators, disease and environmental conditions.
  6. Individuals with characteristics that are best suited to the conditions are more likely to survive and reproduce (survival of the fittest)
  7. The favourable alleles determining these characteristics are passed on to the offspring
25
Q

define the term speciation

A

the production of 2 or more different species from 1 original species as a result of natural selection.
Thought to be how evolution occurs.

26
Q

Describe the the evolution of pesticide resistance in insects and the implications of this for humans

A

Natural selection can result in the development of pesticide resistance in insects - this could affect our crops.
New pesticides are needed and may be found in wild plants that produce toxic chemicals to deter/kill herbivores. Thus maintenance of biodiversity is important as synthetic pesticides are often toxic/harmful to non-harmful insects and can build up in food chains, becoming toxic to other organisms.

27
Q

Describe the evolution of drug resistance in microorganisms and the implications for humans.

A

A population of bacteria may include a few individuals with a chance mutation making them resistant to an antibiotic. These individuals survive when the others are killed by the antibiotic and reproduce rapidly resulting in a new strain of bacteria which are resistant to this antibiotic.

The greater the use of antibiotics by humans, the greater the chance of more resistant strains being naturally selected which could render our use of such antibiotics to treat the strain useless.
This means that it is important to develop new antibiotics to treat bacterial infections. Conservation of biodiversity is crucial to this.

28
Q

Describe how fossils can be used as evidence for evolution

A

Can be dated and put into order to give some evidence of how species may have changed over long time periods
There is also evidence of the past climate and vegetation from the fossil record, so adaptations of organisms can be deduced - e.g. original small 4-toed horses adapted to swampy habitats have changed to the much larger horses with single hoofed toes adapted to grazing and drier grasslands.

29
Q

Describe how DNA genes can be used as evidence for evolution

A

Changes in the DNA base sequences caused by mutations are rare - the similarities and differences between the DNA of different species gives an indication of how closely related they are. More similar DNA = more closely related e.g. diverged from a more recent common ancestor. Can be extracted from fossil bones. e.h. humans and chimpanzees have only 0.87% difference in the coding DNA whereas humans and gorillas have 1.04% difference

30
Q

Describe how molecular evidence can be used as evidence for evolution

A

Genes code for making proteins, so the structure of proteins can be compared to deduce evolutionary relationships. The more similar the protein structure, e.g. its amino acid sequence, the more closely related 2 species are. Used for phylogenetic classification.

31
Q

Outline the reasons for the conservation of animal and plant species, with reference to economic and ecological reasons

A

ecological: Individual species and ecosystems have evolved over millions of years into a complex interdependence - extinction of one may affect whole ecosystems/food chains which could affect us.
economic: wild plants and animal may be used in selective breeding to improve characteristics of crop plants/farm animals and so make more food for us. New medicinal drugs may be discovered from wild plants and microorganisms

32
Q

Outline the reasons for the conservation of animal and plant species with reference to ethical and aesthetic reasons

A

aesthetic: matural habitats, wild plants and animals give many people pleasure - and have been proven to help people with mental and physical diseases to recover.
ethical: human activities cause pollution e.g. industrial wastes which kill many organisms. Production of greenhouse gases such as CO2 from burning fossil fuels is causing climate change which can lead to extinctions. Humans have caused the extinction of species in the past - we should prevent further.

33
Q

discuss the consequences of global climate change on the biodiversity of plants and animals?

A
  • loss of some plants adapted to colder conditions e.g. scottish primrose
  • increase in species adapted to warmer conditions e.g. Resells bush cricket
    Overall decreased biodiversity
34
Q

discuss the consequences of global climate change on agriculture

A
  • different crops may have to be grown in particular areas
  • staple crops e.g. wheat and rice may be affected, resulting in food shortages
  • plant diseases e.g. potato blight fungus spreads rapidly in warm, wet conditions and can destroy whole crops
35
Q

discuss the consequences of global climate change on spread of disease

A
  • malarial mosquitoes, currently mainly in the tropics, may be able to invade Britain
  • pathogens grow more rapidly in warmer conditions, causing greater spread
36
Q

explain the benefits for agriculture of maintaining the biodiversity of animal and plant species

A

Will species of plants and animals may be needed for selective breeding of crop plants and farm animals, which have genetic diversity and may have useful alleles for needed characteristics such as:

  • disease/pest resistance
  • adaptations to warmer climates
37
Q

describe examples of the conservation of endangered plant and animal species in situ

A

In situ conservation is carried out in the natural habitat, e.g.
Conservation parks:
- creation of a reserve,
Lesgislation:
- prevention of hunting threatened species,
- preventing endangered plant species from being dug up/cut down,
- employing local people as wardens/rangers etc.
- providing fencing/water supplies to local people to protect them/their food crops/farm animals from threatened animal species so that they don’t shoot them

38
Q

describe examples of the conservation of endangered plant and animal species ex situ

A

Ex situ conservation is carried out outside the natural habitat e.g.

  • zoos for captive breeding of endangered species with the aim of maintaining genetic diversity and releasing individuals back into the wild
  • botanic gardens are used to conserve rare plant species and act as seed banks to store as sources of genetic diversity for future selective breeding and planting in the wild
  • sperm freezing, articifial insemination, in vitro fertilisation and embryo-transfer thanks to modern technology
39
Q

advantages of ex situ conservation

A

breeding of endangered species can increase the numbers of individuals in an endangered species and enable repopulation by introducing captive-bred animals into the wild.
Protects animals from predators, and their health can be maintained by vets.

40
Q

disadvantages of ex situ conservation

A

expensive
many animals fail to breed successfully as they are not in their natural environments
space and so number of individuals is limited, so genetic diversity is restricted resulting in a lack of variation meaning species is less able to adapt to changing conditions.
Even if the reproduction is successful animals have to survive reintroduction into the wild where they need to find food and survive predation + difficulties with acceptance by existing wild members of their species.

41
Q

advantages of in situ conservation

A
  • plants and animals conserved in their natural environment
  • permanently protects biodiversity and representative examples of ecosystems
  • facilitates scientific research
  • allows management of these areas to ensure that ecological integrity is maintains
  • ecologically sustainable land uses for economic benefits -e.g. outdoor heritage activities/tourist destination
42
Q

disadvantages of in situ conservation

A
  • conflict with local indigenous people who use the land for traditional hunting, spiritual of religious activities
  • poachers/illegal harvesting of timber and other plant products
  • tourists feeding protected animals/leaving litter
  • very large areas needed for some organisms to survive
  • indigenous people might be integral to the balance of an ecosystem by controlling number of predators
43
Q

describe the CITES agreement - aims, what it stands for

A

Convention on International Trade in Endangered Species, decides which species are endangered and how trade in these species should be limited.
Key aims:
- not permitting trade in endangered species
- trade in less threatened species subject to a special export permit/license
- banning trade in materials from endangered species e.g. ivory/tiger skin
- allow trade in artificially propagated plants but prohibit trade in wild plants

44
Q

Discuss the role of an EIA as part of a local planning decision.

A
  • estimate biodiversity & how the development may affect it
  • identify ways in which biodiversity can be conserved
  • identifying endangered species & and any legislations protecting them
  • decide on planning procedures implicated - don’t go ahead/protect/relocate species
45
Q

what is an example of international cooperation in conservation other than the CITES agreement? key aims?

A

Rio Convention on Biodiversity -

  • sustainable use of organisms/habitats/ecosystems
  • share genetic resources and access to scientific knowledge/technology in reference to maintaining biodiversity
  • promotion of ex situ conservation methods

Biology AS (5 decks)

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