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1
Q

Taxonomy

A

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

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2
Q

Phylogeny

A

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

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3
Q

Analogous features

A

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

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4
Q

Homologous features

A

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

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5
Q

Binomial system

A 
Domain             Do
Kingdom          Keep 
Phylum             Pots
Class               Clean
Order               Or
Family            Family
Genus              Gets
Species          Sick
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6
Q

Morphological

A

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
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7
Q

Biological

A

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
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8
Q

Genetic

A

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

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9
Q

Overall Limitations of species models

A 
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
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10
Q

What is gel electrophoresis

A

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.

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11
Q

Process of gel electrophoresis

A
  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.
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12
Q

What does DNA analysis allow us to do?

A

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

DNA Hybridisation and gel elctrophoresis

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13
Q

DNA Hybridisation

A

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

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14
Q

Bioinformatics

A

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.

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15
Q

Peer review process

A

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.
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16
Q

Models of Classification

A

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

Five kingdom model

3 kingdom model

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17
Q

Classification

A

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.

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18
Q

Five kingdom model

A

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

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19
Q

Prokaryote

A

Prokaryotic

Autotrophs and hetrotrophs

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20
Q

Protosctista

A

Eukaryotic

Unicells, colonies and filaments

Autotrophs (algae) and hetrotophs (protozoa)

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21
Q

Fungi

A

Eukaryotic

Cell walls of chitin

All are hetrotrophs

Saprobionts or parasites

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22
Q

Plantae

A

Eukaryotic

Cellulose cell walls

All autotrophs

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23
Q

Animallia

A

Eukaryotic

No cell wall

Multicellular

Hetrotrophs

Develop from a blastocyst

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24
Q

3 kingdom model

A

Archaea

Bacteria

Eukarya

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25
Q

Archaea

A 
Prokaryotic
Circular DNA
No introns
Cell wall present
L-glycerol (ability to live in extreme habitats.
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26
Q

Bacteria

A 
Prokaryotic
Circular DNA
No introns
Peptidoglycan cell wall
Unbranched fatty acids
D-glycerol
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27
Q

Eukarya

A 
Eukaryotic
Linear DNA with histones
Has introns
Cell walls in some (cellulose or chitin)
Unbranched fatty acids
D-glycerol
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28
Q

Autotroph

A

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

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29
Q

Hetrotroph

A

A hetrotroph is an organism that feeds on other organisms.

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30
Q

The endosymbiotic theory

A

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
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31
Q

Evolution

A

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

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32
Q

Process of natural selection

A

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

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33
Q

How many types of selection?

A

There are two different types of natural selection:

Directional Selection

Stabilising Selection

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34
Q

Directional Selection

A

Occurs when one selective pressure is at work

Selection favours an extreme phenotype

This causes the allele frequency to shift

35
Q

Stabilising Selection

A

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

36
Q

What is an ecological niche?

A

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.

37
Q

What is an adaptation?

A

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

38
Q

Physiological adaptations

A

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

39
Q

Behavioural adaptations

A

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

40
Q

Anatomical adaptations

A
  • are features or form that can be seen from the outside or through dissection (beak size, blubber and hairs).
41
Q

What is speciation?

A

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

42
Q

Allopatric Speciation

A

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

43
Q

Sympatric Speciation

A

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

44
Q

Evolutionary race

A

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

45
Q

What causes Antibiotic Resistance

A

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

46
Q

How to mitigate the problem of antibiotic resistance

A

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

47
Q

What is biodiversity?

A

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

48
Q

How can biodiversity be measured?

A

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

49
Q

Genetic diversity

A

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

50
Q

Species richness

A

• 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.

51
Q

Endemism

A

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

52
Q

Why Maintain Biodiversity?

A

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

53
Q

Conservation

A

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

54
Q

Advantages of In-Situ Conservation

A

Habitat and species are saved at the same time

Larger populations can be protected.

55
Q

Disadvantages of In-Situ Conservation

A

Hunting / predation is hard to control

Unavoidable if habitat cannot be saved ,eg, climate change

Hard to enforce legislation

56
Q

In-Situ Conservation

A

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.
57
Q

Ex-Situ Conservation

A

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

58
Q

Zoos

A

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
59
Q

Seedbanks

A

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
60
Q

Advantages of zoos

A

Educate the public

Zoos can carry out research

Increase population numbers

61
Q

Disadvantages of zoos

A

When reintroduced into the wild animals can lack survival skills

Limited success seen so far

62
Q

Advantages of Ex-Situ Conservation

A

Health of individuals can be monitored

Protection from hunting / predation

Mates can be selected to maintain genetic diversity

63
Q

Disadvantages of Ex-Situ Conservation

A

Very expensive

Cannot fully recreate a natural habitat

Disease can quickly spread

Some species don’t breed well in captivity

64
Q

How to calibrate scale in gel electrophoresis?

A

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

65
Q

How many restriction sites in a piece of dna?

A

How many times you have to cut it

e.g 3 pieces means its been cut 2 times

66
Q

Population

A

All the organisms of one species in a habitat

67
Q

Community

A

All the organisms of all the species in a habitat

68
Q

Biodiversity

A

The variety of organisms in an area

69
Q

Species richness

A

The number of different species in a habitat at one time

Measures biodiversity in a habitat

70
Q

Niche

A

The role of an organism in the habitat

71
Q

Endemic species

A

Species that only lives in one geographical area

72
Q

Adaptations

A

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

73
Q

Index of diversity

A

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

74
Q

Reserves vs captive breeding

A
  • 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
75
Q

Natural selection process

A
  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 ;
76
Q

Storing seeds vs whole plants

A

-Smaller so can store more individuals and conserve greater genetic variety

Survive for longer

Maintenance costs are cheaper

77
Q

Population

A

All the organisms of one species in a habitat

78
Q

Community

A

All the population of all the species in a habitat

79
Q

Biodiversity

A

The variety of species in an area

80
Q

Species richness

A

The number of DIFFERENT species in an area

81
Q

Index of diversity

A

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

82
Q

Scientific conferences

A

Meetup of scientists from different institutions

Experts in a specific field

Presentations on latest findings/ results

Scientists can discuss and ask questions

83
Q

The peer review process

A

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

Biology (6 decks)

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