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AS-level biology > biodiversity > Flashcards

biodiversity Flashcards

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1
Q

What is the definition of a hierarchy?

A

smaller groups within larger groups with no overlap

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2
Q

What are the three domains and the 4 kingdoms?

A

Bacteria, Archea

Protista, plantae, Fungi and Animalia

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3
Q

What is a bacteria and what are the features of the bacteria domain?

A

single celled prokaryotes

  • absence of membrne-bounded organelles
  • unicellular (cells may occur in chains or clusters)
  • ribosomes are smaller (70s) than eukaryotes
  • cell walls are present and made of murein
  • single loop of DNA (no histones)
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4
Q

What is an Archaea and are the features of the Archaea domain?

A

group of single-celled prokaryotes

differ from bacteria:

  • their genes and protein synthesis more similar eukaryotes
  • their membranes contain fatty acid chains attached to glycerol by ester linkages
  • no muerin in cell walls
  • have a more complex form of RNA polymerase
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5
Q

What is a Eukarya and are the features of the Eukarya domain?

A

made up of one or more eukaryotic cells

  • their cells possess membrane-bounded organelles
  • they have membranes containing fatty acid chains attached to glycerol by ester linkages
  • cell walls do not muerin
  • 80s ribosomes
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6
Q

What is the acronym for taxonomy?

A

Delicious, King Prawn Curry Or Fat Greasy Sausages

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7
Q

What is phylogeny?

A

the study of evolutionary relationships between organisms

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8
Q

What are 5 agricultural practices that can directly reduce biodiversity

A
  1. Woodland clearance - to increase the area of farmland
  2. Hedgerow removal - increase the area of farmland turning lots of small fields into fewer large fields
  3. Overgrazing land, thereby preventing regeneration of woodland due to soil erosion
  4. Filling in ponds and draining march and other wetland
  5. Monoculture - fields containing only one type of plant
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9
Q

What are three Indirect agricultural practices that can reduce biodiversity

A
  1. Pesticides - chemicals that kill organisms (pests) that feed on crops
  2. Escape of effluent from silage stores dn slurry tanks into water courses
  3. absence of crop rotation and lack of intercropping or undersowing
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10
Q

Name examples of conservation techniques

A
  • Maintain existing hedgerows at the most beneficial height and shape
  • plant hedges instead of fences and field borders
  • Maintain existing ponds
  • Plant native trees on land with a low species diversity making their species-rich areas
  • Use crop rotation that includes a nitrogen-fixing crop, rather than fertilisers to improve soil fertility
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11
Q

Why are hedgerows important for wildlife?

A

they act as wildlife corridors = species are able to move to uncultivated areas, without them the species are more exposed and vulnerable

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12
Q

Why are monocultures bad?

A

very low diversity and prone to pests so more pesticides used

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13
Q

Why is the use of inorganic fertilisers bad?

A

Inorganic fertilisers are very soluble, they runoff into lakes where eutrophication leads to overgrowth of algae

  • This blocks sunlight so aquatic plants below the surface of the water start to die as they can no longer photosynthesise
  • As aquatic plants and algae die in increasing numbers, decomposing bacteria feed on the dead organic matter and also increase in number
    • As they respire aerobically, these bacteria use up the dissolved oxygen in the water
  • As a result, the amount of dissolved oxygen in the water rapidly decreases, so aquatic organisms such as fish and insects may be unable to survive
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14
Q

What are homologous structures?

A

similar physical features in organisms that share a common ancestor, but the features serve completely different functions

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15
Q

What are analogous structures?

A

observable features that look alike and perform similar functions does not mean that they have a close evolutionary relationship.

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16
Q

What are the limitations of using observable characteristics?

A
  • a large number of characteristics are polygenic. This means they are not discete from one another but rather vary continuously.
  • Characteristics can also be modified by the environment. Differences may therefore be the result of different environmental conditions instead of different alleles
17
Q

What are the 4 different techniques for comparing genetic diversity within, and between species?

A
  • observable characteristics
  • base sequence of DNA
  • base sequence of mRNA
  • amino acid sequence of proteins
18
Q

Describe the concept of comparison of DNA base sequences to investigate the diversity

A

During the evolution of a new species, the DNA will initially be very similar to that of the species that gave rise to it.

Due to mutations the sequence of nucleotides in the DNA of the new species will change and over time there will be an accumulation in the differences in its DNA

so closely related species in evolutionary history will show more similarity in their DNA than distantly related ones

DNA sequencing is now routinely done by automatic machine and data produced analysed by computers.

In these computerised systems, each nucleotide base can be tagged with a different coloured fluorescent dye.

These can be used to compare genetic diversity and evolutionary relationships.

19
Q

Describe the concept of comparison of MRNA base sequences to investigate the diversity

A

mRNA is coded for by DNA during transcription.

The base sequence of mRNA are complementary to those of the strand of DNA from which they were made.

It follows that we can measure DNA diversity, and therefore genetic diversity, by comparing the base sequence of mRNA.

20
Q

Describe the concept of comparison of amino acid sequences to investigate the diversity

A

The sequence of amino acids in proteins is determined by DNA.

The degree of differences in the amino acid sequence of the same protein in two species will reflect how closely related the two species are.

The sequences can be compared by counting either the number of similarities or differences.

21
Q

Give one reason why DNA analysis has been useful in the field of taxonomy (4)

A
  • gene sequences can be compared to establish relatedness
  • can give more detail than observable differences
  • it can establish evolutionary history
  • can allow comparison with an extinct species to be made
22
Q

What is the definition of courtship behaviour and what is it’s purpose?

A

A behaviour that results in mating, to enable species recognition

23
Q

test the effects of antibiotics using Agar plates

A

use a sterile pipette to transfer the bacteria from the broth to an agar plate.

spread the bacteria over the plate using a sterile plastic spreader

use sterile forceps to place paper discs soaked with different antibiotics spaced apart on the plate.

Make sure you add a negative control disc soaked only in sterile water

lightly tape a lid on, invert, and incubate the plate at about 25 degrees for 48 hours.

the size of the inhibitation zone tells you how well an antibiotic works.

The larger the zone, the more the bateria were inhibited from growing.

A similar technique can be used to test the effects of antiseptics or disinfectants on microbial growth

24
Q

why are aseptic techniques used

A

they are used to prevent contamination of cultures by unwanted microogranims.

this is important because contamination can affect the growth of the microorganism that you are working with

also because contamination with disease-causing microbes that could make you ill

25
Q

what aseptic techniques must be used when testing the teffects of antibiotics using Agar plates

A

regularly disinfect work surfaces to minimise contamination. Dont put any utensils on the work surface . contaminated utensils should be placed in a beaker of disinfectant

use sterile equipment and discard after use

minimise the time spent with the lid off the agar plate, to reduce the chance of airborne microorganims contaminating the culture

work near a bunsen flame. hot air rises, so any microbes in the air should be drawn away from your culture

briefly flame the neck of the glass container of broth just after its opened and just before its closed this causes air to move out of the container, preventing unwanted organims from falling

26
Q

what is directional selection

A

where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce

AS-level biology (30 decks)

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