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Question 1

Taxonomy

Answer 1

Taxonomy - the science of describing and classifying living things based upon physical similarities.

Question 2

Phylogeny

Answer 2

Phylogeny - classification based upon evolutionary relationships determined by DNA or RNA.

Question 3

Analogous features

Answer 3

Analogous features - look similar and have the same function but do not have the same origin.

Question 4

Homologous features

Answer 4

Homologous features - show genuine common ancestry (pentodactyl limb).

Question 5

Binomial system

Answer 5

Domain             Do
Kingdom          Keep 
Phylum             Pots
Class               Clean
Order               Or
Family            Family
Genus              Gets
Species          Sick

Question 6

Morphological

Answer 6

This looks at appearance and physical characteristics. Those animals that look similar will be put into the same category and be defined as a species.

• Does not account for sexual dimorphism
• Organisms change over time making some hard to trace through the fossil record

Question 7

Biological

Answer 7

This defines a species as a group of organisms with similar characteristics that can reproduces to form fertile offspring.

• Does not account for asexual reproduction
• Some animals have never been seen mating so we are only presuming that they do

Question 8

Genetic

Answer 8

An organisms DNA is analysed and compared with another sample. The degree of similarity determines if they are from the same species.

How “similar” do they need to be for them to be classed as the same species
DNA can degrade over time
The genome of animals changes significantly over long periods of time

Question 9

Overall Limitations of species models

Answer 9

Finding evidence
When does a hybrid become a new species
Some do not account for asexual reproduction
Fossils need to be accounted for
Sexual dimorphism
Some species mimic each other

Question 10

What is gel electrophoresis

Answer 10

An example of a technique used in molecular phylogeny is gel electrophoresis:

Gel electrophoresis, as well as DNA sequencing and bioinformatics, can be used to distinguish between species and determine evolutionary relationships.

Question 11

Process of gel electrophoresis

Answer 11

1. Make wells in agarose jelly
2. Put DNA fragments cut with restriction endonuclease enzyme in them (known and unknown).
3. Attach a fluorescent label or stain DNA fragments
4. Turn on a current.
5. DNA is negatively charged so it moves towards the anode. Small fragments move faster and so further
6. Turn the current off.
7. Turn the UV light on.
8. Different bands represent different amino acids and can be compared to known fragments.

Question 12

What does DNA analysis allow us to do?

Answer 12

DNA analysis allows us to asses the similarities between two organisms. This can be achieved using two different techniques.

DNA Hybridisation and gel elctrophoresis

Question 13

DNA Hybridisation

Answer 13

Samples of DNA from each organism are taken and heated in separate tubes

The hydrogen bonds break releasing the double helix

The two samples are mixed

The less hydrogen bonds that reform when these two samples are mixed the less similar the organisms are

The number of hydrogen bonds present can be determined by the temperature at which the two strands of DNA separate

Question 14

Bioinformatics

Answer 14

This is the use of technology and software to analyse large amounts of biological data, spotting patterns and trends.

This enables comparisons of entire genomes to be made, looking at mutations and how many there are to create a phylogenetic tree.

These mutations may have caused a divergence in the phylogenetic tree allowing relationships between organisms to be mapped out.

Question 15

Peer review process

Answer 15

When new research is completed, it must first be validated by the scientific community.
The process is as follows:

Published in a journal
The sent to experts for review
This checks for validity
Presented at a conference
Questions are asked
This is known as the scientific method of enquiry.

Question 16

Models of Classification

Answer 16

There are currently two major models of classification structure. These are outlined below:

Five kingdom model

3 kingdom model

Question 17

Classification

Answer 17

Classification is the process of naming and organising organisms into groups based on their characteristics.

Organisms can be grouped into one of the five kingdoms: animals, plants, fungi, prokaryotes and protoctists.

They can then be grouped further into phylum, class, order, family, genus and species.

Each species is named according to the binomial system, the first part of the name is the genus and the second part of the name is the species e.g. Homo sapiens.

Question 18

Five kingdom model

Answer 18

This model relies heavily on physical observations. In light of new DNA sequencing and molecular phylogency the model was revised. The new model better shows evolutionary relationships.

Prokaryote

Protosctista

Fungi

Plantae

Animallia

Question 19

Prokaryote

Answer 19

Prokaryotic

Autotrophs and hetrotrophs

Question 20

Protosctista

Answer 20

Eukaryotic

Unicells, colonies and filaments

Autotrophs (algae) and hetrotophs (protozoa)

Question 21

Fungi

Answer 21

Eukaryotic

Cell walls of chitin

All are hetrotrophs

Saprobionts or parasites

Question 22

Plantae

Answer 22

Eukaryotic

Cellulose cell walls

All autotrophs

Question 23

Animallia

Answer 23

Eukaryotic

No cell wall

Multicellular

Hetrotrophs

Develop from a blastocyst

Question 24

3 kingdom model

Answer 24

Archaea

Bacteria

Eukarya

Question 25

Archaea

Answer 25

``` Prokaryotic Circular DNA No introns Cell wall present L-glycerol (ability to live in extreme habitats. ```

Question 26

Bacteria

Answer 26

``` Prokaryotic Circular DNA No introns Peptidoglycan cell wall Unbranched fatty acids D-glycerol ```

Question 27

Eukarya

Answer 27

``` Eukaryotic Linear DNA with histones Has introns Cell walls in some (cellulose or chitin) Unbranched fatty acids D-glycerol ```

Question 28

Autotroph

Answer 28

An Autotroph is an organism that synthesises its own food using an external energy source.

Question 29

Hetrotroph

Answer 29

A hetrotroph is an organism that feeds on other organisms.

Question 30

The endosymbiotic theory

Answer 30

The endosymbiotic theory provides compelling evidence that all life on Earth has a common ancestor. The theory is as follows: - A large host cell ingested a bacteria - This bacteria was not consumed - The ingested cell became useful to the host - This created a symbiotic relationship

Question 31

Evolution

Answer 31

Evolution is defined as a long lasting change in the frequency of alleles of a single gene within a population. This processes is brought about through natural selection

Question 32

Process of natural selection

Answer 32

Genetic variation occurs through meiosis and point mutations This results in new alleles being created This new allele may be advantageous The organism is now more likely to survive Leading to differential reproductive success The advantageous allele is passed on to any offspring The frequency of this allele increases Resulting in evolution

Question 33

How many types of selection?

Answer 33

There are two different types of natural selection: Directional Selection Stabilising Selection

Question 34

Directional Selection

Answer 34

Occurs when one selective pressure is at work Selection favours an extreme phenotype This causes the allele frequency to shift

Question 35

Stabilising Selection

Answer 35

Occurs when two selective pressures are at work This happens in well adapted populations where the most advantageous allele is also the most common Deviations away from the optimum result in a disadvantage

Question 36

What is an ecological niche?

Answer 36

An ecological niche is a description of where a species can successfully exist taking into account abiotic and biotic factors. Biotic - factors are living factors such as competition with other organisms. Abiotic - factors are non-living factors such as temperature and pH. After considering all of these factors it is possible to describe its niche on a graph.

Question 37

What is an adaptation?

Answer 37

An adaptation is any feature that allows an organism to survive, feed or protect itself more effectively within its environment.

Question 38

Physiological adaptations

Answer 38

describe how an organism works, specifically regarding enzymes and biological pathways (extremophiles).

Question 39

Behavioural adaptations

Answer 39

are instinctive decisions that animals make to increase their chance of survival (migration, group hunting and courtship rituals).

Question 40

Anatomical adaptations

Answer 40

- are features or form that can be seen from the outside or through dissection (beak size, blubber and hairs).

Question 41

What is speciation?

Answer 41

This is the formation of a new species as a result of evolution and natural selection. It occurs when organisms become reproductively isolated. There are two types of speciation: Allopatric Sympatric

Question 42

Allopatric Speciation

Answer 42

Geographical isolation Reproductive isolation (no gene flow) Variation exists in the population due to mutations Different selection pressures leads to the directional selection of different phenotypes There is differential reproductive success This causes a change in allele frequency over many generations

Question 43

Sympatric Speciation

Answer 43

Reproductive isolation (no gene flow) - Morphological: different shaped gentalia - Seasonal: reproductively active at different times - Behavioural: Different courtship behaviour - Hybrid sterility: Hybrids of 2 parents are infertile Variation exists in the population due to mutations Different selection pressures leads to the directional selection of different phenotypes There is differential reproductive success This causes a change in allele frequency over many generations

Question 44

Evolutionary race

Answer 44

Natural selection also works on bacterial populations. This means there is an evolutionary race between pathogenic bacteria and the development of antibiotics that treat them. The introduction of an antibiotic provides favourable conditions to resistant strains These are more likely to survive thus giving rise to antibiotic resistant bacteria

Question 45

What causes Antibiotic Resistance

Answer 45

This is a major problem in the health sector and has been caused by the following factors: Antibiotics are too widely prescribed Lots are used to treat symptoms in the hope that one will work Patients don't complete the full course Lack of basic hygiene No financial incentive for firms to develop new drugs

Question 46

How to mitigate the problem of antibiotic resistance

Answer 46

However, there are a number of things we can do to mitigate these problems: Reduce use Improve education Develop new ways to target bacteria Develop new antibiotics

Question 47

What is biodiversity?

Answer 47

Biodiversity is the variety of living organisms. Biodiversity can be measured in terms of: Biodiversity

Question 48

How can biodiversity be measured?

Answer 48

Biodiversity can be measured in terms of: • Species richness • Genetic diversity

Question 49

Genetic diversity

Answer 49

• Genetic diversity - a measure of the genetic variation found in a particular species, in other words the number of alleles in a gene pool.

Question 50

Species richness

Answer 50

• Species richness - the number of different species in a habitat. Takes into account the number of individuals of each species .An index can be found using the following formula: D = [N(N-1)] / [Σn(n-1)] N = number of all organisms of all species n = number of individuals of each species The larger the index, the greater the diversity.

Question 51

Endemism

Answer 51

Endemism is the state of a species being unique to a particular geographic location, such as an island, and not found anywhere else

Question 52

Why Maintain Biodiversity?

Answer 52

Ecotourism Resources for non medical reasons , building materials species have the right to exist Aesthetic pleasure Keystone species are a species that play a vital role in maintaining an ecosystem. If they are removed the ecosystem collapses. Its especially important to conserve these species

Question 53

Conservation

Answer 53

Conservation can be in-situ (in an organism's habitat) or ex-situ (outside of an organism’s habitat).

Question 54

Advantages of In-Situ Conservation

Answer 54

Habitat and species are saved at the same time Larger populations can be protected.

Question 55

Disadvantages of In-Situ Conservation

Answer 55

Hunting / predation is hard to control Unavoidable if habitat cannot be saved ,eg, climate change Hard to enforce legislation

Question 56

In-Situ Conservation

Answer 56

This is conservation within the natural environment. Methods can include restoration and legislation. * Education programmes which aim to educate people about the importance of maintaining biodiversity, captive breeding programmes as well as illegal trade of animal products. * Initatives such as National Parks and Sites of Specific Scientific Interest aim to conserve habitats and biodiversity.

Question 57

Ex-Situ Conservation

Answer 57

This is the conservation of plants and animals outside of their natural habitat (zoos and seed banks). • Seedbanks store a large number of seeds in order to conserve genetic diversity and prevent plant species from going extinct. Storing seeds instead of plants means that a large variety of species can be conserved, it’s also cheaper than storing whole plants as it takes up less space. The seeds are stored in cool, dry conditions as this maximises the amount of time they can be stored for and they are periodically tested for viability. In

Question 58

Zoos

Answer 58

These are an example of ex-situ conservation. Animals are placed into an artificial habitat and usually enter a captive breeding programme. - DNA profiling is used to select mates who are less related to each other - Breeding records are kept and animals are moved between zoos - This is to prevent inbreeding Reintroduction programmes: - Prepare individuals for release by reinforcing wild behaviour - Suitable release site is selected - The local population are educated

Question 59

Seedbanks

Answer 59

Seeds from many plants of the same species are stored - to maintain genetic diversity Seeds are x rayed to see if they are viable Storage: - Dry and cold - to prevent enzyme activity that could start germination - Clean/ sterilise the seeds - Regularly test their viability during storage and if viability falls bellow 75%, collect fresh seeds - Low O2 - Dark

Question 60

Advantages of zoos

Answer 60

Educate the public Zoos can carry out research Increase population numbers

Question 61

Disadvantages of zoos

Answer 61

When reintroduced into the wild animals can lack survival skills Limited success seen so far

Question 62

Advantages of Ex-Situ Conservation

Answer 62

Health of individuals can be monitored Protection from hunting / predation Mates can be selected to maintain genetic diversity

Question 63

Disadvantages of Ex-Situ Conservation

Answer 63

Very expensive Cannot fully recreate a natural habitat Disease can quickly spread Some species don't breed well in captivity

Question 64

How to calibrate scale in gel electrophoresis?

Answer 64

You can calibrate the scale by using pieces of DNA of known length

Question 65

How many restriction sites in a piece of dna?

Answer 65

How many times you have to cut it | e.g 3 pieces means its been cut 2 times

Question 66

Population

Answer 66

All the organisms of one species in a habitat

Question 67

Community

Answer 67

All the organisms of all the species in a habitat

Question 68

Biodiversity

Answer 68

The variety of organisms in an area

Question 69

Species richness

Answer 69

The number of different species in a habitat at one time Measures biodiversity in a habitat

Question 70

Niche

Answer 70

The role of an organism in the habitat

Question 71

Endemic species

Answer 71

Species that only lives in one geographical area

Question 72

Adaptations

Answer 72

Organisms evolve by natural selection to become better adapted to their niche This increases their chances of reproduction and survival These adaptations can be: Behavioural Anatomical Physiological

Question 73

Index of diversity

Answer 73

Describes the relationship between the number of species in a community and the number of individuals in each species.

Question 74

Reserves vs captive breeding

Answer 74

- Less stressful for animals - More likely to breed in their natural environment - Some animals may need large animals - Avoid difficulties of releasing animals eg, habituation - Disease is less likely - Maintain their niche

Question 75

Natural selection process

Answer 75

1. genetic variation in population due to mutations 2. description of selection pressure ; 3. idea that some individuals possessed { advantageous } characteristics ; 4. (therefore) survived to adulthood / survived to breed ; 5. passing on {advantageous alleles / eq} (to offspring) / eq ; 6. change in allele frequency (over generations) / eq ; 7. idea of {geographical / reproductive} isolation ;

Question 76

Storing seeds vs whole plants

Answer 76

-Smaller so can store more individuals and conserve greater genetic variety Survive for longer Maintenance costs are cheaper

Question 77

Population

Answer 77

All the organisms of one species in a habitat

Question 78

Community

Answer 78

All the population of all the species in a habitat

Question 79

Biodiversity

Answer 79

The variety of species in an area

Question 80

Species richness

Answer 80

The number of DIFFERENT species in an area

Question 81

Index of diversity

Answer 81

Describes the relationship between number of species in a community and the number of individuals of each species

Question 82

Scientific conferences

Answer 82

Meetup of scientists from different institutions Experts in a specific field Presentations on latest findings/ results Scientists can discuss and ask questions

Question 83

The peer review process

Answer 83

Before an article can be published in a scientific journal, independent scientists critically read/analyse articles to check data analysis Errors are corrected before publication Not a perfect process, but is the best practical system to achieve unbiased, reliable results