biodiversity

Question 1

What is the definition of a hierarchy?

Answer 1

smaller groups within larger groups with no overlap

Question 2

What are the three domains and the 4 kingdoms?

Answer 2

Bacteria, Archea

Protista, plantae, Fungi and Animalia

Question 3

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

Answer 3

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)

Question 4

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

Answer 4

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

Question 5

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

Answer 5

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

Question 6

What is the acronym for taxonomy?

Answer 6

Delicious, King Prawn Curry Or Fat Greasy Sausages

Question 7

What is phylogeny?

Answer 7

the study of evolutionary relationships between organisms

Question 8

What are 5 agricultural practices that can directly reduce biodiversity

Answer 8

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

Question 9

What are three Indirect agricultural practices that can reduce biodiversity

Answer 9

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

Question 10

Name examples of conservation techniques

Answer 10

• 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

Question 11

Why are hedgerows important for wildlife?

Answer 11

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

Question 12

Why are monocultures bad?

Answer 12

very low diversity and prone to pests so more pesticides used

Question 13

Why is the use of inorganic fertilisers bad?

Answer 13

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

Question 14

What are homologous structures?

Answer 14

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

Question 15

What are analogous structures?

Answer 15

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

Question 16

What are the limitations of using observable characteristics?

Answer 16

• 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

Question 17

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

Answer 17

• observable characteristics
• base sequence of DNA
• base sequence of mRNA
• amino acid sequence of proteins

Question 18

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

Answer 18

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.

Question 19

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

Answer 19

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.

Question 20

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

Answer 20

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.

Question 21

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

Answer 21

• 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

Question 22

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

Answer 22

A behaviour that results in mating, to enable species recognition

Question 23

test the effects of antibiotics using Agar plates

Answer 23

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

Question 24

why are aseptic techniques used

Answer 24

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

Question 25

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

Answer 25

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

Question 26

what is directional selection

Answer 26

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