Species etc

Question 1

What is a species? (2)

Answer 1

1. Group of similar organisms / organisms with similar features / / organisms with same genes/chromosomes2. that reproduce to produce fertile offspring

Question 2

A forest was cleared to make more land available for agriculture. After the forest was cleared the species diversity of insects in the area decreased. Explain why. (4)

Answer 2

1. Decrease in variety of plants / fewer plant species2. Fewer habitats/niches3. Decrease in variety of food / fewer food sources4. Aspect of clearing forest (killing insects) eg machinery, pesticides

Question 3

Organisms can be classified using a hierarchy of phylogenetic groups. Explain what is meant by:1. a hierarchy2. a phylogenetic group

Answer 3

1. 1. Groups within groups 2. No overlap (between groups)2. (Grouped according to) evolutionary links/history/relationships / common ancestry;

Question 4

What is intraspecific variation?

Answer 4

Variation / differences within the same/a species

Question 5

There are ethical and economic arguments for maintaining biodiversity. Suggest one ethical argument for maintaining biodiversity and one ECONOMIC argument for doing so.

Answer 5

(We should maintain biodiversity to)1. Prevent extinction /loss of populations 2.reduction in populations /loss of habitats 3. save organisms for future generationsECONOMICA suitable example of how some species may be important financially e.g.1. medical / pharmaceutical uses;2. commercial products / example given;3. tourism;4. agriculture;5. saving local forest communities

Question 6

Give two ways in which courtship increases the probability of successful mating.

Answer 6

1. Attracts/recognises same species2. Attracts/recognises mate/opposite sex3. Indication of sexual maturity/ fertility / synchronises mating4. Stimulates release of gametes5. Form pair bond

Question 7

Frequent treatment with the antibiotic vancomycin can result in resistant strains of bacteria. Explain how.

Answer 7

1. Mutation present/occurs2. Resistance gene/allele3. Resistant bacteria (survive and) reproduce4. Vertical (gene) transmission / Horizontal (gene) transmission / conjugation

Question 8

The gene for resistance to vancomycin is very common in the bacterium Enterococcus faecalis. The same gene has now been found in the bacterium Staphylococcus aureus.Use your knowledge of gene transmission to explain how the gene was passed from one species of bacterium to another.

Answer 8

1. Horizontal (gene) transmission2. Via conjugation/pilus3. Plasmid/Gene/DNA replicated/copied4. Plasmid transferred (to S.aureus)

Question 9

Scientists can use protein structure to investigate the evolutionary relationships between different species. Explain why.

Answer 9

1. Amino acid sequences / primary structure2. Closer the (amino acid) sequence the closer the relationship3. (Protein structure) related to (DNA) base/triplet sequence

Question 10

Comparing the base sequence of genes provides more evolutionary information than comparing the structure of proteins. Explain why.

Answer 10

1. Reference to base triplets/triplet code / more bases than amino acids / longer base sequence than amino acid sequence2. Introns / non-coding DNA3. of code / more than one code for each amino acid

Question 11

Explain what is meant by genetic diversity.

Answer 11

Difference in DNA/base sequence / difference in alleles/genes/gene pool

Question 12

Apart from genetic factors what other type of factor causes variation within a species?

Answer 12

Environmental

Question 13

The spotted owl is a bird. Numbers of spotted owls have decreased over the past 50 years. Explain how this decrease may affect genetic diversity.

Answer 13

Reduced (genetic diversity)As fewer different/varied alleles/genes / reduced gene poo(Genetic) bottleneck

Question 14

Costa Rica is a Central American country. It has a high level of species diversity.There are over 12 000 species of plants in Costa Rica. Explain how this has resulted in a high species diversity of animals. (2)

Answer 14

Greater variety / different foodsMore habitats/niches

Question 15

The number of species present is one way to measure biodiversity. Explain why an index of diversity may be a more useful measure of biodiversity.

Answer 15

Also measures number of individuals in a species / different proportions of speciesSome species may be present in low/high numbers

Question 16

An order is a taxonomic group. Fruit flies and mosquitoes belong to the same order of insects. Name the other three taxonomic groups to which fruit flies and mosquitoes both belong.

Answer 16

Kingdomphylum and class

Question 17

Explain what is meant by a phylogenetic relationship.

Answer 17

Shows evolutionary relationship

Question 18

What information is required to calculate an index of diversity for a particular community?

Answer 18

Number of a / each species

Question 19

Farmers clear tropical forest and grow crops instead. Explain how this causes the diversity of insects in the area to decrease.

Answer 19

1. Lower diversity of plants/ few species of plants/less variety of plants/few plant layers2. Few sources/types of food/feeding sites3. Few habitats/ niches4. Fewer (species of) herbivore so few (species of)carnivores5. Aspect of agriculture (killing insects)

Question 20

What are the benefits and risks of deforestation?

Answer 20

Benefits: wood and land for homes to be builtlocal areas become more developedRisks:diversity is reducedless carbon dioxide is stored because there are fewer plants and trees which contributes to climate changenatural beauty is lost

Question 21

What are the ways argiculture reduces diversity?

Answer 21

1) wooland clearance2) headgerow removal3) monoculture4) pesticides5) herbicides

Question 22

Scientists’ analysis of blood proteins has indicated a lack of genetic diversity in populations of some organisms. Describe the processes that lead to a reduction in the genetic diversity of populations of organisms.

Answer 22

1. Mark for general principle of - reduced variety/number of different alleles/DNA / reduced gene pool (in new population)2. Founder effect3. A few individuals from a population become isolated/form colonies4. (Genetic) bottlenecks5. (Significant) fall in size of population6. Selective breeding / artificial selection7. Using organisms with particular alleles/traits/phenotypes/characteristics

Question 23

Saskia explain what is meant by a hierarchy.

Answer 23

Groups within (larger) groupsNo overlape.g.

Question 24

Explain why it may be more useful to calculate the index of diversity than to record only the number of species present.

Answer 24

Measures number of individuals (of each species) and number of species;Some species only present in small numbers

Question 25

The demand for increased food production has led to areas of heath being used to grow wheat. Explain the effect of this on the species diversity of plants

Answer 25

Reduced as one crop/species grown / other species removedUse of herbicides/weeding/ploughingWheat (better) competitor for named factor e.g. light/nutrients

Question 26

The demand for increased food production has led to areas of heath being used to grow wheat. Explain the effect of this on the species diversity of animals

Answer 26

Reduced) as less variety of food sources(Reduced) as fewer habitats/niches; (Reduced) by pesticides/chemicals

Question 27

Give two ways in which courtship behaviour increases the probability of successful mating.

Answer 27

Recognition of same speciesStimulates release of gametesRecognition of mate/opposite genderIndication of sexual maturity/fertility

Question 28

Scientists studied two species of North American seahorse. They thought that these two species are closely related. Describe how comparisons of biological molecules in these two species could be used to find out if they are closely related. (6)

Answer 28

(Compare) DNA;Sequence of bases/nucleotides; *****DNA hybridisation ******** Separate DNA strands / break hydrogen bondsMix DNA/strands (of different species)Temperature/heat required to separate (hybrid) strands indicates relationshipCompare same/named proteinSequence of amino acids /primary structureInject (seahorse) protein/serum into animal(Obtain) antibodies/serumAdd protein/serum/plasma from other (seahorse) speciesAmount of precipitate indicates relationship

Question 29

Interspecific variation

Answer 29

When one species differs from another species

Question 30

Intraspecific variation

Answer 30

When members of the same species differ from each other.

Question 31

What is sampling?

Answer 31

This involves taking measurements of individual, selected from the population being investigated. If these individuals are representative then the measurements can be relied upon.

Question 32

Sampling bias:

Answer 32

The selection process may be biased. The investigators may make unrepresentative choices.

Question 33

The best way to prevent sampling bias is to eliminate human involvement in choosing the samples. This can be achieved by random sampling. Describe how (3)

Answer 33

1) Divide study area into a grid of numbered lines.2) Using random numbers obtain a series of coordinates.3) Take samples at the intersection of each pair of coordinates.

Question 34

Variation is the result of two main factors

Answer 34

genetic differences and environmental influences

Question 35

How do genetic differences occur (3)

Answer 35

These are due to the different genes that each individual organism possessed. These change from generation to generation. Genetic variation occurs as a result of:Mutations: These sudden changes to genes and chromosomes may be passed to the next generation.Meiosis: This form of nuclear division forms the gametes. This mixes the genetic material before it is passed to the gametes.Fusion of gametes: In sexual reproduction, offspring inherit some characteristics of each parent. Which gamete fused with which a random process adds to variety

Question 36

Name 5 environmental influences for plants

Answer 36

- Light- Climatic conditions- Soil conditions- pH- Food availability

Question 37

what is Selective breeding or atrificial selection?

Answer 37

It involves selecting individuals with desired characteristics and using then to parent the next generation.Offspring that don’t exhibit the characteristics are killed or prevented from breeding.The variety of alleles in the population is deliberately restricted to a small number of desired alleles.

Question 38

What is the founder effect

Answer 38

- Occurs when few individuals colonise a new region.They carry with them only a small fraction of the alleles of the population.These alleles may not be representative.The new population that develops from the few colonisers will show less genetic diversity than the population they came from.

Question 39

What are Genetic bottle necks

Answer 39

Populations may sometimes suffer a drop in numbers.This may be due to things such as a volcanic eruption or interference by man.The few survivors will possess a smaller variety of alleles than the original population.As they breed and become re-established the genetic diversity will remain restricted

Question 40

Commnet on the Ethics of selective breeding:

Answer 40

-Interfering with nature?- Animal rights and welfare?- Is it beneficial to the environmental?- Cost?

Question 41

reasons for courtship behaviour

Answer 41

``` recognise member sod the same species attract opposite sex identifying mate of breeding capability synchronise product of eggs and sperm form bond pair ```

Question 42

protein immunology steps

Answer 42

1. rabbit injected with protein from species a 2. rabbit produces antibodies in an immune response 3. collect blood serum from rabbit- with antibodies 4. mix serum with proteins from different species. The stronger the ppt, the closer evolutionary relationship since there are more antibodies protein complexs

Question 43

order of classification

Answer 43

``` kingdom phylum class order family genum species ```

Question 44

classification

Answer 44

groups organisms based on common features they share

Question 45

5 kingdoms

Answer 45

animalia, protista, fungi, plantae, monera

Question 46

when do new species arise

Answer 46

when a population is separated and mutations occur

Question 47

problem with selective breeding

Answer 47

1. Inbreeding / breed closely related organisms; 2. (So higher probability of) mutations being passed on / recessive alleles being expressed / health problems/example given / increase in genetic disease; 3. Reduced genetic variation/diversity / smaller gene pool / less variety of alleles; 4. (So) can be killed by/susceptible to the same/a disease / reduces ability to adapt/survive (future) environmental changes / may not be beneficial to future breeding programmes;