⭐️Genetic Info, Variation And Relationships: Biodiversity

Question 1

What is the definition of a species?

Answer 1

Organisms that share a large number of common characteristics and so can interbreed and produce fertile offspring

Question 2

What is the binomial system

Answer 2

The system that uses two names to identify organisms through genus and species

Question 3

What are the rules of using the binomial system in scientific writing?

Answer 3

• The names are typed in italics or underlined when handwritten
• the first letter of the genus is capital and the first letter of the species is lowercase
• if the species isn’t known it can be written after the genus as sp

Question 4

Why don’t members of two different species reproduce?

Answer 4

Because the offspring being the hybrid will end up sterile because they would have an odd number of chromosomes so they wouldn’t pair up during meiosis. This means the offspring of two different species is a waste of energy because it can’t go on to pass down its genes to the next generation.

Question 5

What do sign stimuli allow for organisms?

Answer 5

To make sure they have recognised their own species and chosen the organism with the best characteristics for sexual reproduction

Question 6

Why are courtship and mating essential?

Answer 6

In order for the species to survive so that their DNA can be passed on to through the reproductive process to the next generation

Question 7

Give 5 ways courtship ensures successful mating

Answer 7

By allowing members of a species to:

• recognise members of their own species to make sure mating only takes place between members of the same species to produce fertile offspring
• to identify a mate that’s capable of breeding as both partners need to be sexually mature, fertile and receptive to mating
• to form a pair bond that will lead to successful mating and raising of offspring
• to synchronise mating so it takes place when there’s the maximum possibility of sperm and egg cell fusing
• to become able to breed by bringing a member of the opposite sex into a phycological state that allows breeding to occur

Question 8

How do males use courtship behaviour?

Answer 8

To determine wether the female is in the window where they are receptive to mating

Question 9

What is classification?

Answer 9

Grouping of organisms

Question 10

What is a hierarchy?

Answer 10

Where the groups are within groups and the groups don’t overlap

Question 11

What is taxonomy?

Answer 11

The theory and practise of biological classification

Question 12

What are the two types of biological classification?

Answer 12

Phylogenetic classification and artificial classification

Question 13

What is each group of the classification system called?

Answer 13

A taxon

Question 14

List all the taxa in the classification system

Answer 14

Domain 
Kingdom 
Phylum 
Class 
Order 
Family 
Genus 
Species

Question 15

What is artificial classification based on?

Answer 15

• not based on evolutionary relationships
• groups of organisms are instead based on analogous characteristics (characteristics with the same function but different evolutionary origin e.g. the wings of butterflies and birds are both used for flight but originated in different ways)

Question 16

What is phylogenetic classification? What is it based on?

Answer 16

• groups of species using shared features derived from common ancestors e.g. the pentadactyl limb and arranges groups on a hierarchy where there is no overlap between them
• based on evolutionary relationships

Question 17

What are the three domains?

Answer 17

Bacteria, archaea (a group of prokaryotes ) and eukarya

Question 18

State what bacteria are and give five features they possess

Answer 18

A group of single celled prokaryotes

• lack membrane bound organelles e.g. nuclei/ mitochondria
• they are unicellular although may occur in chains/ clusters
• they have smaller 70s ribosomes (eukaryotic cells have 80s)
• the cell walls are present but made of murein (never chitin or cellulose)
• they contain a single loop of naked dna with NO HISTONES

Question 19

State what archaea are and 4 features they possess

Answer 19

• their genes and protein synthesis are more similar to eukaryotes
• their membranes contain fatty acid chains attached to glycerol by ether linkages
• there is no murein in their cell walls
• they have a more complex form of RNA polymerase

Question 20

State what are eukarya and 4 features they possess

Answer 20

They are a group of organisms made up of one or more eukaryotic cells

• their cells have membrane bound organelles like mitochondria or chloroplasts
• they have membranes containing fatty acid chains attached to glycerol by ester linkages
• not all have cells with a cell wall but where they do it doesn’t contain murein
• the ribosomes are 80s so are larger than in bacteria and archaea

Question 21

What are the four divisions of the eukarya domain?

Answer 21

Proctista, fungi, plantae and animalia

Question 22

What is phylogeny?

Answer 22

The evolutionary relationship between organisms and can be represented as a phylogenetic tree

Question 23

What are the three components of biodiversity that allow it to relate to a range of habitats from and what do they each refer to?

Answer 23

• species diversity = the number of different species and the number of individuals of each species within any one community
• genetic diversity = the variety of genes possessed by the individuals that make up a population of a species
• ecosystem diversity = the range of different habitats from a small local habitat to the whole earth

Question 24

Give the two measures of species diversity and state what they each are.

Answer 24

• Species richness and is the number of different species in a particular area at a given time ( so number of species in a community)
• species evenness which is the relative abundance of different species in a given area

Question 25

How can you measure the species diversity?

Answer 25

Using an index that’s calculated (check biology camera roll for the index and how to use it)

Question 26

Define ecosystem

Answer 26

A community and its abiotic environment

Question 27

Define community

Answer 27

The biotic component of an ecosystem

Question 28

Define population

Answer 28

The number of individuals of a particular species in a given area at a given time

Question 29

What does a high index value suggest?

What does a low index value suggest?

Answer 29

• a high index value suggests a stable site with many different niches and low competition (so high richness and evenness)
• a low index value suggests a site with few potential niches where only a few species dominate ( so low richness and evenness)

Question 30

How are agricultural ecosystems different to natural ecosystems?

Answer 30

With time natural ecosystems develop a high index of diversity where as agricultural ecosystems are controlled by humans where farmers select species for certain qualities and reduce the variety of alleles that they possesses.

Question 31

What are the two reasons the index of species diversity is low in agricultural ecosystems? What does this reduce overall?

Answer 31

-due to the genetic variety of alleles in the species being reduced, most of the area is taken up by one species and so there is a smaller area for other species and they will have to compete for the little space and resources that are available causing many to not survive as only few will adapt hence reducing the population of the species.
-use of pesticides excludes species as they compete for light, water, mineral ions and food required by the farmed species
Overall, these techniques of agricultural farming reduce biodiversity

Question 32

What 4 practises have directly removed habitats and reduced species diversity?

Answer 32

• removal of hedgerows and grubbing out woodland
• creating monocultures e.g. replacing natural meadows with cereal crops or grass for silage
• filling in ponds and draining marsh and other wetland
• over grazing of land e.g. upland areas by sheep, thereby preventing regeneration of woodland

Question 33

What practices have indirectly removed habitats and reduced species diversity?

Answer 33

• use of pesticides and inorganic fertilisers
• escape of effluent from silage stores and slurry tanks into water courses
• absence of crop rotation and lack of intercropping or under sowing

Question 34

What is the reason there are ways to balance intrusive food production and conservation?

Answer 34

To increase the species and habitat diversity without unduly raising food costs or lowering yields

Question 35

Give 7 examples of techniques used to balance conservation and farming

Answer 35

• plant hedges instead of erect fences as field boundaries
• to leave wet corners of the field instead of drain them
• to plant native trees on land with a low species diversity rather than in species rich areas
• to reduce the use of pesticides and use biological control or gm organisms that are resistant to pests
• use intercropping rather than herbicides to control weeds and other pests
• leave the cutting of verged and field edges until after flowering and when the seeds have dispersed
• introduce conservation headlands (areas at the edges of fields where pesticides are used restrictively so wild flowers and insects can breed

Question 36

How can you decide how closely related two species are?

Answer 36

By looking at the degree of similarity in the amino acid sequence of the same protein in the two species

Question 37

What has inferring DNA differences from observable characteristics been replaced by?

Answer 37

Directly observing DNA sequences themselves through the advances in gene technology