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Biology > Module 4 - Classification and Evolution > Flashcards

Module 4 - Classification and Evolution Flashcards

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1
Q

Why do we classify organisms?

A

To identify species and avoid confusion.
To predict characteristics - if several members in a group have a characteristic, it is likely that another species in the group will have the same characteristic.
Find evolutionary links - common ancestors etc

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2
Q

What is the difference between classification and taxonomy?

A

Grouping of organisms is classification and the theory and practice of classification is taxonomy.

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3
Q

What is the difference between taxonomy and phylogeny?

A

Taxonomy is a form of classification that focuses on similarities between species.
Phylogeny shows evolutionary relationships between organisms so that every group has a common ancestor.

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4
Q

What is artificial classification?

A

Artificial classification divides organisms according to observable similarities and differences eg colour, size, leaf shape etc
It doesn’t reflect evolutionary relationships.

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4
Q

What is natural classification?

A

Based upon evolutionary relationships between organisms and their shared features are derived from their ancestors.
It can change with advancing knowledge.

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5
Q

What are two descendants that split from the same group on the taxonomic hierarchy called?

A

Sister groups.

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6
Q

What does it mean if the branches on the tree of the taxonomic hierarchy are close?

A

They are closely related.

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7
Q

What is the order of the levels of heirarchy?

A

D KP COF GS
(Domain, kingdom, phylum, class, order, family, genus, species)

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8
Q

What is binomial naming and what do the two parts mean?

A

The first part means the genus and starts with a capital letter.
The second part means the species that the organism belongs to.

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9
Q

What are the 5 kingdoms in classification?

A

Prokaryotae (bacteria) (the rest are eukaryotes)
Protoctista
Fungi
Plantae
Animalia

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10
Q

What are the general features of a prokaryote? (5)

A

-Unicellular.
-No nucleus or other membrane bound organelles
-A ring of ‘naked’ DNA
-Small ribosomes
-No visible feeding mechanism (either absorbed through cell wall or produced by photosynthesis)

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11
Q

What are examples of a prokaryote?

A

Bacteria

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12
Q

What are the general features of protoctista? (5)

A

-Most are unicellular.
-Have a nucleus and other membrane bound organelles
-Some have chloroplasts.
-Some are sessile but others move by cilia, flagella or amoeboid mechanism.
-Nutrients are acquired by photosynthesis (autotrophic) or ingestion of other organisms (heterotrophic).

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13
Q

What are examples of a protoctista?

A

Amoeba proteus, paramecium, euglena.

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14
Q

What are the general features of fungi? (8)

A

-Unicellular or multicellular.
-Have a nucleus and other membrane-bound organelles.
-Have a cell wall composed of chitin.
-No chloroplasts, no chlorophyll.
-No mechaism for locomotion.
-Most have a body or mycelium made of threads or hyphae.
- Saprotrophic feeders.
- Most store their food as glycogen (insoluble)

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15
Q

What are examples of a fungi?

A

Mushrooms, mould, yeast.

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16
Q

What are the general features of plantae? (7)

A

-Multicellular.
- Have a nucleus and other membrane bound organelles.
- Have chloroplasts and chlorophyll.
- Cell walls consist of cellulose.
-Most don’t move (some gametes can move using cilia/flagella)
- Nutrients acquired by photosynthesis (autotrophic)
-Store food as starch.

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17
Q

What are the general features of animalia? (7)

A

-Multicellular.
-Have a nucleus and other membrane-bound organelles.
-No cell walls.
-No chloroplast.
-Move with the aid of cilia, flagella or contractile proteins sometimes in the form of muscular organs.
-Heterotrophic feeders
-Food stored as glycogen

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18
Q

Examples of animalia? (not the obvious ones)

A

Sponges and anemones

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19
Q

What is molecular systematics?

A

The study of genetics and biological male-up of organisms to classify them.
It also uses DNA, RNA and proteins.

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20
Q

How can you tell evolutionary relationships from molecular systematics?

A

Similarities between DNA and the proteins of the different species.

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21
Q

Why do we expect closely related organisms to show more similarity in their DNA?

A

Because when organisms split from a common ancestor they get further apart genetically over time due to mutations, so similar DNA signals that they split from a common ancestor more recently.

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22
Q

What is the 3 domain system and what does it acknowledge?

A

Acknowledges;
-DIfferences in sequence of nucleotides in the cells rRNA.
- Differences in the cells’ membrane structure.
- Sensitivity to antibiotics.

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23
Q

What are the 3 domains in the 3 domain system?

A

Eukarya
Archaea
Bacteria

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24
Q

What are the features of Eukarya in the 3 domain system in terms of ribosomes and proteins?

A

Have 80s ribosomes,
RNA polymerase contains 12 proteins.

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25
Q

What are the features of Archaea in the 3 domain system in terms of ribosomes and proteins?

A

70s ribosomes,
RNA polymerase contains 8-10 proteins.

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26
Q

What are the features of Bacteria in the 3 domain system?

A

70s ribosomes,
RNA polymerase contains 5 proteins.

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27
Q

What are the structural differences between bacteria and the other 2 domains in the 3 domain system?

A

-DIfferent cell membrane structure.
-Flagella with different internal structure.
-DIfferent enzymes for synthesising RNA.
-No proteins bound to their genetic material.
-Different mechanisms for DNA replication and synthesising RNA.

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28
Q

Why are archaebacteria and eubacteria classified in their own kindgom?

A

They have different chemical makeup.
Eubacteria contain peptidoglycan in their cell walls, archaebacteria don’t.

29
Q

What are archaebacteria?

A

Ancient bacteria - can live in extreme conditions.

30
Q

What are eubacteria?

A

Found in all environments, more familiar bacteria.

31
Q

What is the theory of natural selection?

A

Organisms are all involved in a struggle for life.
They must compete for resources.
Individuals who are better adapted are more likely to survive and reproduce.
The advantageous characteristics are passed into the offspring.
Gradually a species will change over time to have more of the advantageous phenotype to the environment that they live in.
These characteristics are passed on in genes by DNA.

32
Q

What was Darwin’s book about evolution by natural selection?

A

On the Origin of Species

33
Q

What example with birds on the Galapagos island showed adaptation and evolution?

A

The finches beaks were adapted to the food sources on each island.

34
Q

What are the three evidences for evolution?

A

Paleontology - study of fossils.
Comparative anatomy - study of similarities and differences between organisms anatomy.
Comparative biochemistry - Similarities and differences between the chemical makeup of organisms.

35
Q

How do fossils support the theory that simple life forms gradually evolve over time?

A

Fossils of the simplest organisms like algae and bacteria are found in the oldest rock and more complex organisms are found in more recent rocks.

36
Q

How can fossils be used to show how closely related organisms have evolved from a common ancestor?

A

Studying anatomy of fossil records. They allow relationships between living and extinct organisms to be found.

37
Q

What are the limitations of using the fossil record to study evolution?

A

Soft-bodied organisms decompose quickly before they can be fossilised.

38
Q

What is homologous structure of anatomy?

A

Homologous structure is one that appears to be superficially different but has the same underlying structure (whale fin and human arm)

39
Q

What is divergent evolution?

A

A feature that has evolved for different functions over time in different organisms.

40
Q

What are two of the most common molecules studied in comparative biochemistry? Why?

A

Cytochrome C
Ribosomal RNA (rRNA)
These are studied because the variability in these molecules occurs outside of the functional regions so there is no effect on the function. These are called ‘neutral’ changes.

41
Q

How can we tell the point in time that two species shared a common ancestor?

A

We know the rate that substitutions (mutations) takes place. If you know the avg mutation rate you can extrapolate when the two had a common ancestor.

42
Q

What parent is mitochondrial DNA passed from to the offspring?

A

Mother.

43
Q

How is mitochondrial DNA used to trace the path of evolution?

A

mDNA has a higher rate of mutation than nuclear DNA so there is lots of variation in the sequence of mDNA from different parts of the world.

44
Q

What is the Multiregional Hypothesis?

A

That humans evolved simultaneously in different parts of the world.

45
Q

What are the processes of natural selection to form a new species?

A

Genetic variation - new alleles arise by mutations.
Better adapted organisms are more likely to survive and reproduce and less adapted organisms are more likely to die.
Alleles are passed on to offspring.
Over many generations the species can evolve so much it becomes a new species.

46
Q

What are the three conditions for evolution?

A

Variation - must be differences between the individuals in a population.
Heredity - differences must be heritable.
Means of selection - there must be a mechanism or pressure that selects some variables for the next generation at the expense of others.

47
Q

How does antibiotic-resistance show evolution?

A

Use of antibiotics is a powerful selection pressure on bacteria.
When you take antibiotics most of the bacteria are killed.
However, due to mutations some are resistant and survive (especially if full course isn’t completed)
Resistant bact. survive and reproduce to pass on the alleles that give antibiotic resistance to create a resistant strain of bacteria.
Eg MRSA

48
Q

What is intraspecific variation?

A

Variation that exists between different species. Example a lion and a limpet.

49
Q

What is interspecific variation?

A

Variation that exists within a species.

50
Q

What is continuous variation?

A

Where there are two extremes and a full range of intermediate values between those extremes.
They are controlled by many genes and are affected by environmental factors.

51
Q

What graph can be used to show continuous variation?

A

Histogram

52
Q

What is discontinuous variation?

A

There are two or more distinct categories with no intermediate values.
Usually controlled by a single gene and are not affected by environmental factors.
Eg human blood groups.

53
Q

What type of graph would be used to represent discontinuous variation?

A

Bar graph

54
Q

What are the causes of variation?

A

Genetic differences and/or environmental influences.

55
Q

What causes genetic differences?

A

Mutations
Meiosis
Random fusion of gametes

56
Q

What are epigenetics, give an example?

A

Environment influencing gene expression. Himalayan rabbits are white but the gene responsible for dark pigment is only activated at less than 35 degrees.

57
Q

How do you work out the mean?

A

Add up all values and divide by the number of values you added together/

58
Q

How do you calculate the median?

A

Put all values into order and the middle value is the median.

59
Q

How do you calculate mode?

A

Most frequent value.

60
Q

How do you calculate range?

A

Difference between highest and lowest value.

61
Q

How do you calculate percentage error?

A

Percentage error = uncertainty / reading x 100

62
Q

What is the standard deviation equation?

A

…

63
Q

How do you add the standard deviation to bars or plotted points on a graph?

A

Error bars,
They extend one standard deviation above the mean and one standard deviation above the mean and one below, therefore the full length of the error bar is twice the standard deviation.

64
Q

What can we tell if the error bars overlap?

A

We can be less certain about any differences between any data.

65
Q

What do we use correlation coefficients for?

A

To determine if a correlation is significant.

66
Q

What is the spearman’s rank formula?

A

…

67
Q

What does the value of the spearman’s rank mean?

A

The result will be between -1 and 1.
Negative number shows a negative correlation.
Positive number shows a positive correlation.
Further away from zero the stronger the correlation.

68
Q

What is the null hypothesis in spearman’s rank?

A

A null hypothesis must be written for a statistical test, eg there is no significant correlation between foot length and hand span.
Data must then be analysed to see if the null hypothesis should be accepted or not.

69
Q

When should you accept and reject the null hypothesis?

A

If your calculated value is greater than the critical value, reject it. This means that there is less than 0.05% possibility that the results are due to chance.
If your calculated value is less than the critical value, accept the null hypothesis. There is less than 0.005% probability that the results are due to chance.

Biology (19 decks)

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