OCR A BIOLOGY > 4.3 - classification & evolution > Flashcards

4.3 - classification & evolution Flashcards

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1
Q

What is classification?

A

The arrangement of organisms into groups of various sizes on the basis of shared features.

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2
Q

What is the binomial system?

A

A system that uses the genus name and the species name to avoid confusion when naming organisms.

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3
Q

Why do we classify living things?

A
  • convenience
  • make the study of living things more manageable
  • easier to indentify organisms
  • to help us see the relationships between species
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4
Q

What are the eight parts to the modern classification hierarchy?

A
  • Domain
  • Kingdom
  • Phyllum
  • Class
  • Order
  • Family
  • Genus
  • Species
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5
Q

What are the 3 domains?

A
  • archaea
  • eubacteria
  • eukaryotae
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6
Q

Which of the four kingdoms have a nucleus?

A
  • plantae
  • animalia
  • fungi
  • protoctista
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7
Q

What is the kingdom that doesn’t have a nucleus?

A

prokaryotae

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8
Q

What is the binomial naming system?

A

A universal naming system that uses the genus and the species.

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9
Q

What are the features of the binomial naming system?

A

The genus has a capital letter, and the species is written in all lower case.

Italics are used in printed text whereas the name is underlined when handwritten.

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10
Q

What is the biological definition of species?

A

The group of organisms that can freely interbreed to produce fertile offspring.

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11
Q

What is the phylogenetic definition of a species?

A

A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics.

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12
Q

What is the description of the kingdom animalia?

A
  • Eukaryotic
  • multi cellular
  • usually able to move around
  • heterotrophic
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13
Q

What does heterotrophic mean?

A

When you digest large organic molecules into smaller ones that can then be absorbed.

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14
Q

What does autotrophic mean?

A

When you absorb simple molecules with larger organic ones.

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15
Q

Was a description of the kingdom fungi?

A
  • eukaryotic
  • chitin cell walls
  • single-celled or have mycelium
  • multinucleate cytoplasm
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16
Q

Was a description of the kingdom plantae?

A
  • eukaryotic
  • multi cellular
  • cellulose cell walls
  • contain chlorophyll
  • autotrophic
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17
Q

What is the description of the kingdom protoctista?

A
  • eukaryotic
  • mostly single celled
  • mostly free-living
  • plant-like or animal-like features
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18
Q

What is the description of the kingdom prokaryotae?

A
  • no nucleus
  • naked DNA (no histones)
  • smaller ribosomes
  • no membrane-bound organelles
  • smaller cells
  • DNA loop with non-linear chromosomes
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19
Q

What is taxonomy?

A

A form of classification that focuses on physical similarities between different species for ease of naming and identification.

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20
Q

What is phylogeny?

A

The classification of organisms by their evolutionary relationships so that every group shares a common ancestor.

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21
Q

What is the problem with artificial classification?

A

Sometimes different animals aren’t related, but look very similar due to convergent evolution, which leads to species being put into the same genus of family when they shouldn’t be.

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22
Q

What is artificial classification based on?

A
  • observable characteristics
  • diet
  • habitat
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23
Q

What is natural classification based on?

A
  • genetics
  • reproductive relationships
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24
Q

What evidence is used in classification?

A
  • cytochrome C
  • DNA
  • the 3 domains
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25
What is cytochrome c?
a protein used in respiration by all organisms, however it is not identical in all species
26
how can cytochrome C be used?
We can compare the sequence of amino acids in samples of cytochrome C from 2 different species.
27
What can what two conclusions can be made when comparing cytochrome C from 2 different species?
1. if the sequences are the same, the 2 species must be closely related. 2. If the sequence is different, the two species aren't closely related.
28
How can DNA be used as evidence in classification?
DNA is a universal code for all organisms. You can compare the DNA sequences to help classify the species.
29
What features do archae share with eukaryotes?
- Similar enzymes for synthesising RNA - Similar mechanisms for DNA replication and RNA synthesis - Production of same proteins that for bind for DNA.
30
What is natural selection?
where features of the environment apply selective force on the reproduction of individuals in a population.
31
Who published papers on evolution by natural selection?
Charles Darwin and Alfred Russell Wallace.
32
What four observations did Darwin make?
1. offspring generally appear similar to their parents 2. no two individuals are identical 3. organisms have the ability to produce large numbers of offspring 4. populations in nature tend to remain fairly stable in size.
33
How can Darwin's conclusions be summarised?
There is a struggle to survive. The better adapted individuals survive and pass on their characteristics. Over time a number of changes may give rise to a new species.
34
What is the evidence for evolution?
- Fossil evidence, - biological molecules
35
How can fossils provide evidence for evolution?
Old species have died out, and new species have taken their place, often with similar characteristics.
36
How can biological molecules provide evidence for evolution?
- All species arose from uncommon ancestor so certain biological molecules are found in all species - too closely related species who have separated recently, will have biological molecules that are the same or very similar - cytochrome C
37
What is continuous variation?
Quantitive features (can be measured) and are controlled by genes and the environment.
38
What is discontinuous variation?
Qualitative features, it is controlled by genes.
39
What is environmental variation?
Variation caused by response to environmental factors such as light intensity.
40
What is genetic variation?
Variation caused by possessing a different number of alleles
41
What is interspecific variation?
The differences between different species.
42
What is intraspecific variation?
The variation between members of the same species.
43
What is variation?
The presence of variety, or the differences between individuals.
44
What are examples of continuous variation?
- Height in humans - length of leaves on an oak tree - length of the stalk of a toadstool - Number of flagella on a bacterium.
45
What are examples of discontinuous variation?
- Gender - some bacteria have flagella but some don't - human blood groups.
46
How can the causes of variation be categorised?
Genetic or environmental.
47
What is the correlation coefficient?
A measure of how closely two sets of data are correlated.
48
What is standard deviation?
A measure of the spread around the mean.
49
What is students t test?
A test used to compare two means.
50
What does a low standard deviation show?
A narrow range, potentially greater reliability.
51
What does a high standard deviation show?
A large range, potentially lower reliability.
52
What are the degrees of freedom.
The number of values in a statistical calculation that are free to vary. sample size - the number of data sets
53
What significance level should you always consider?
95%
54
When would the difference be considered insignificant when doing the t test?
If the calculated value of T is lower than the 5% value
55
How can both the environment and genetics affect variation?
The environment may affect which genes are active. Humans may be taller due to genetics and a better diet.
56
What are examples of environment affecting variation?
- an overfed pet becoming obese - tan skinned due to sunlight exposure - The amount of growth of the plant could also be affected.
57
What is adaptation?
A characteristic that enhances survival in the habitat.
58
What is anatomical adaptations?
Structural features.
59
What are behavioural adaptations?
The ways that behaviour is modified for survival.
60
What are physiological adaptations?
They affect for ways that processes work.
61
What will a well adapted organism be able to do?
- find enough food and water or photosynthesise well - gather enough nutrients - defend itself from predators or diseases - respond to changes in the enironment - have suficient energy to allow successful reproduction - survive the physical conditions of its environment
62
How does natural selection work?
1. mutation creates an alternative version of a gene 2.This creates genetic diversity between individuals of the species 3. there is a selection pressure 4. individuals with an advantageous characteristic will survive and reproduce 5. they pass pn their advantageous characteristic to offspring 6. the next generation will have a high proportion of individuals with the successful characteristics.
63
What is essential for evolution to take place?
Genetic variation.
64
What are examples of modern day evolution?
Pesticide resistance in insects and antibiotic resistance in bacteria.
65
What are three types of adaptation?
- Anatomical - behavioural - physiological.
66
What is an example of convergent evolution
Moles and Masupial moles. They are an unrelated species with separate evolutions, but they share a number of characteristics and look similar.
67
How does having a thick waxy cuticle work?
Reduces evaporation from the cells of the leaf.
68
What is the most accurate way for comparing species?
Comparing the base sequence for amino acids as you can also see mutations.
69
What is directional selection?
where individuals are favoured in one direction, which is the extreme which causes the mean to change.
70
What is stabilising selection?
Where the average individuals are favoured, this means the mean stays the same and there are fewer extremes.
71
When would the t test be used
If the data is normally distributed and there is a sample size of less than 25.
72
What is the difference between a paired and unpaired t test?
A paired t test is used when there is the same individual, whereas the unpaired T test is used when there are different individuals.
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