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Biology A Level > :) classification And Evolution > Flashcards

:) classification And Evolution Flashcards

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1
Q

What’s the point of classification?

A

Makes it easier for scientists to identify them and study them

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2
Q

What’s taxonomy?

A

The study of classification

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3
Q

How many different classifications are there?

A

A few

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4
Q

What do all the classifications systems involve?

A

Placing organisms into groups in a taxonomic hierarchy

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5
Q

What are the eight levels of groups used in classification?

A 
Domain
Kingdom
Phylum 
Class
Order
Family 
Genus
Species
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6
Q

How are similar organisms first sorted?

A

Into one of three very large group called domain

e.g. Animals, plants and fungi are in the Eukarya domain

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7
Q

After domains how similar organisms sorted?

A

Into slightly smaller groups called kingdoms e.g. All animals are in the animal kingdom

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8
Q

After kingdoms how similar organisms sorted?

A

Into a phylum

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9
Q

After phylum how similar organisms sorted?

A

Class and so on down the eight levels of the taxonomic hierarchy

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10
Q

What happens as the move down the hierarchy?

A

There are more groups at each level but fewer organisms in each group

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11
Q

What does the hierarchy end with?

A

Species-the group that contains only one type of organism

E.g. Human, dog, E-coli and about 50 million other living species

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12
Q

What’s the naming system used for classification?

A

The nomenclature for classification is called the binomial system

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13
Q

What are all organisms given?

A

One internationally accepted scientific name in Latin and has two parts

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14
Q

What is the first part of an organism Latin name?

A

The genus name and has a capital letter and underlined

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15
Q

Second part of the genus name is?

A

The species name and begins with a lower case letter

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16
Q

What are humans in the binomial system?

A

Homo sapiens

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17
Q

Names are written

A

In italics or underlined if handwritten

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18
Q

What does binomial system help to avoid?

A

The confusion of using common names
E.g. Over 100 different plant species are called raspberries and one species of buttercup has over 90 different common names

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19
Q

What is classification?

A

The act of arranging organisms into groups based on their similarities and differences

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20
Q

What are the five kingdoms?

A 
Prokaryotae 
Protoctista
Fungi 
Plantae 
Animalia
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21
Q

Example of prokaryotae

A

Bacteria

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22
Q

Features of prokaryotae?

A

Prokaryotic, unicellular (single cell), no nucleus, less than 5 micrometres

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23
Q

Protoctista examples?

A

Algae

Protozoa

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24
Q

Protoctista features?

A

Eukaryotic cells, usually live in water, single-celled or simile multicellular organisms

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25
Q

Fungi examples

A

Moulds, yeasts, mushrooms

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26
Q

Features of fungi

A

Eukaryotic, chitin cell wall, saprotrophic (absorb substances from dead or decaying organisms), single-celled or multicellular organisms

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27
Q

Plantar examples

A

Mosses
Ferns
Flowering plants

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28
Q

Plantae features?

A

Eukaryotic, multicellular, cell walls made of cellulose, can photosynthesis, contain chlorophyll, autotrophic (produce own food)
Photoautotrophs (produce own food using light)

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29
Q

Animalia examples?

A

Nematodes (roundworms), molluscs, insects, fish, reptiles, birds, mammals

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30
Q

Features of Animalia?

A

Eukaryotic
Multicellular
No cell walls
Heterotrophic (consume plants and animals)

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31
Q

What is phylogeny?

A

The study of evolutionary history of groups of organisms

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32
Q

What does phylogeny tell us?

A

Who’s related to whom and and how closely related they are

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33
Q

All organisms have evolved from what?

A

Shared common ancestors (relatives)

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34
Q

Can organisms being evolved from shared common ancestor be shown?

A

On a phylogenetic tree

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35
Q

What does a phylogenetic tree show for one on primates?

A

The relationship between members of the Hominidae family (great ape and humans).

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36
Q

What does the first branch point represent?

A

A common ancestor of all family members. Ancestor is now extinct

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37
Q

What does orangutan were the first group to diverge?

A

Evolve to become from a different species from the common ancestor
Goes on top branch with no sub branches

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38
Q

What does each of the branch points represent?

A

Another common ancestor from which a different group diverged. Gorillas diverged next then humans, closely followed by bonobos and chimpanzees.

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39
Q

According to phylogenetics what’s a species?

A

The smallest group that shares a common ancestor
The end branch on a phylogenetic tree
(Phylogenetic species concept)

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40
Q

When did closely related species diverge away from each other?

A

Most recently
E.g. Humans and chimpanzees are closely related as they diverged very recently. You can see this because their branches are close together. Humans and orangutan a are more distantly related as they diverged longer ago so branches are further apart

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41
Q

Classification systems now do what with phylogeny?

A

Take into account when arranging organisms into groups

Classifying organisms in this way is called cladistics

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42
Q

Classification systems are they fixed?

A

No classification systems and groups organisms are placed in aren’t set in stone. New technology and evidence can lead to changes in these systems and the reclassification of organisms.

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43
Q

What did early classifications systems use?

A

Only used observable features (things you can see) to place organisms into groups e.g. Whether they lay eggs, can fly or can photosynthesis

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44
Q

What’s the problem with only using observable features for classification?

A

Scientists don’t always agree on the relative importance of different features and groups based solely on physical features may not show related organisms are.

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45
Q

Give an example of flaw with only using observable features for classification?

A

Sharks and whales look quite similar and they both live in the sea. But they aren’t actually closely related. Whales are mammals and sharks are cartilaginous fish-two completely different classes

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46
Q

What are classification systems now based upon?

A

On observation features along with other evidence

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47
Q

What tell us how related organisms are?

A

The more similar organisms are, the more related they are. We now use a wide range of evidence to see how similar and therefore how related organisms are

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48
Q

Give four examples of evidence used in classification systems now?

A

Molecular evidence
Embryological evidence
Anatomical evidence
Behavioural evidence

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49
Q

How can molecular evidence be used to classify organisms?

A

The similarities in proteins and DNA. More closely related organisms will have more similar molecules

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50
Q

Give two examples of molecular evidence?

A

Can compare things like how DNA is stored and the sequence of DNA bases
Can compare sequence of amino acids in proteins from different organisms

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51
Q

Can compare things like how DNA is stored and the sequence of DNA bases example

A

E.g. Base sequence for human and chimpanzee DNA is about 94% the same

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52
Q

Can compare sequence of amino acids in proteins from different organisms
Example

A

Cytochrome C is a short protein find in many species. The more similar the amino acid sequence of cytochrome C in two different species the more closely related the species are likely to be

53
Q

Embryological evidence

A

Similarities in early stages of an organisms development

54
Q

Anatomical evidence

A

Similarities in structure and function of different body parts

55
Q

Behavioural evidence

A

Similarities in behaviour and social organisation of organisms

56
Q

What do new technologies mean for classification?

A

New technologies (new DNA techniques, better microscopes) can result in new discoveries being made and relationships between organisms being clarified

57
Q

Scientists can share these new findings where and what can happen as a result?

A

In meetings and scientific journals

How organisms are classified is continually revised to take account of any new findings that scientists discover

58
Q

Give example of how new findings can change classification?

A

Skunks were classified in family Mustelidae until molecular evidence revealed their DNA sequences was significantly different to other members of that family. So they were reclassified into family Mephitidae

59
Q

In older systems the largest groups were?

A

The five kingdoms all organisms were placed into one of these groups

60
Q

What happened in 1990?

A

The three domain system was proposed

This new system has three domains- large super kingdoms that are above the kingdoms in the taxonomic hierarchy

61
Q

What happened to kingdom Prokaryotae in the three domain system?

A

Are separated into two domains the Archaea and Bacteria

Kingdom prokaryotae contained unicellular organisms without a nucleus

62
Q

What is placed in domain Eukarya?

A

Organisms with cells containing a nucleus

Animalia, plantae, fungi and protoctista

63
Q

What’s the new hierarchy

A 
Domain 
Kingdom 
Phylum 
Class
Order 
Family 
Genus 
Species
64
Q

Why was the three domain system proposed?

A

New evidence mainly molecular
E.g. Prokaryotae were reclassified into two domains because new evidence showed large differences between the Archae and Bacteria

65
Q

What were the two types of evidence for the two domains of prokaryotae?

A

Molecular evidence- enzyme RNA polymerase is different in Bacteria and Archaea but not bacteria have similar histones to Eukarya
Cell membrane evidence- bonds of lipids in cell membrane in Bacteria and Archaea are different. Development and composition of flagellae are also different

66
Q

What’s enzyme RNA polymerase needed for?

A

To make RNA

67
Q

What’s histone?

A

Proteins that bind to DNA

68
Q

What do scientists now agree about Archaea and Bacteria?

A

Evolved separately and Archaea are more closely related to Eukarya than Bacteria. The three domain system reflects how different Archaea and Bacteria are.

69
Q

What is the development of the three domain system?

A

An example of how scientific knowledge is always changing and improving

70
Q

What is variation mean?

A

The difference that exists between individuals

71
Q

Is every individual organism unique?

A

Yes even clones (…identical twins) show variation

72
Q

Where can variation occur?

A

Within species

Between species

73
Q

Within species variation?

A

Intraspecific variation
E.g. Individual European robins weigh between 16g and 22g and show some variation in many other characteristics including length, wingspan, colour and beak size

74
Q

Between species variation

A

Interim specific variation
E.g. Lightest species of birds is the bee hummingbird, which weighs around 1.6g on average. The heaviest species of bird is the ostrich, which can weigh up to 160kg (100000 times as much)

75
Q

What can variation be?

A

Continuous or discontinuous

76
Q

What’s continuous variation?

A

When the individuals in a population vary within a range- there are no distinct categories e.g. Humans can be any height within a range (139,175,185.9cm) not just tall or short.

77
Q

Animals continuous variation examples?

A

Milk yield-e.g. Cows can produce any volume of milk within a range
Mass-e.g. Humans can be any mass within a range

78
Q

Plants continuous variation?

A

Number of leaves- e.g. A tree can have any number of leaves within a range
Mass-e.g. The mass of the seeds from a flower bed varies within a range

79
Q

Microorganisms continuous variation?

A

1) width-e.g. The width of E-coli bacteria varies within a range
Length- e.g. The length of the flagellum can vary within a range

80
Q

What’s discontinuous variation?

A

When there are two or more distinct categories- each individual falls into only one of these categories, there are no intermediates

81
Q

Discontinuous variation animals?

A

Blood group- e.g. Humans can be group A,B, AB or O

82
Q

Discontinuous variation plants

A

Colour- e.g. Courgettes are either yellow, dark green or light green
Seed shape- e.g. Some pea plants have smooth seeds and some have wrinkled seeds

83
Q

Microorganisms discontinuous variation?

A

Antibiotic resistance- e.g. Bacterium are either resistant or not
Pigment production- e.g. Some types of bacteria can produce a coloured pigment, some can’t

84
Q

What can variation be caused by?

A

Genetic factors, environmental factors or a combination of both

85
Q

Different species have?

A

Different genes

86
Q

Individuals of the same species have?

A

The same species but different alleles

87
Q

What make up an organisms genotype?

A

The genes and alleles an organism have

88
Q

What does the difference in genotype result in?

A

Variation in phenotype

Phenotype- the characteristics displayed by the organism

89
Q

Examples of variation only caused by genetic factors include?

A

Blood groups in humans (O,A,B,AB) and antibiotic resistance in bacteria

90
Q

Where do you get your genes from?

A

Your parents meaning variation caused by genetic factors is inherited

91
Q

Other than genes what else can cause variation?

A

Difference in environment e.g. Climate, food, lifestyle.

92
Q

What happens to characteristics controlled by environmental factors over an organism’s life?

A

They can change

93
Q

Examples of variation caused by environmental factors?

A

Accent

Whether people have pierced ears

94
Q

Genetic factors determine what?

A

The characteristics an organism is born with

95
Q

But what can environmental factors influence?

A

How some characteristics develop

96
Q

Name two examples of variation caused by genes and environmental factors?

A

Height- genes determine how tall an organism can grow but diet or nutrient availability affect how tall an organism actually grows
Flagellum- genes determine if a microorganism can grow a flagellum but some only start to grow in certain environments e.g. Metal ions present

97
Q

What do you do to investigate variation usually?

A

Take a sample of a population

98
Q

What is the mean?

A

An average of values collected in a sample

Can be used to tell if there is variation between samples

99
Q

What do most samples include?

A

Values either side of the mean so you end with a bell-shaped graph
(Normal distribution
Symmetrical around mean)

100
Q

What does standard deviation tell you?

A

How much the values in a single sample vary. It’s a measure of spread of values about the mean

101
Q

How will you sometimes see the mean written

A

9±3

This means the mean is 9 and the standard deviation is 3 so the values are spread between 6 and 12

102
Q

What does a large standard deviation mean?

A

The values in the sample vary a lot. A small standard deviation tells you that most of the sample vary a lot

103
Q

A small standard deviation?

A

Most of the sample data is around the mean value so varies little

104
Q

Standard deviation formula

A

(Σ (x-mean)^2/n-1)^1/2

105
Q

Using standard deviation

A 
Write out equation 
Work out mean 
Work out (X-mean) for every x
Add all numbers together
Divide by n-1 
Square root answer
106
Q

What does being adapted to an environment mean?

A

An organism has features that increase its chances of survival and reproduction and also the chances of its offspring reproducing successfully

107
Q

What are these features called?

A

Adaptations

108
Q

What can adaptations be?

A

Behavioural
Physiological
Anatomical

109
Q

In each generation who survived?

A

The best- adapted individuals are more likely to survive and reproduce passing their adaptations on to their offspring. Individuals that are less well adapted are more likely to die before reproducing

110
Q

Behavioural adaptations?

A

Ways an organism acts that increase its chance of survival

111
Q

Behavioural adaptations examples

A

Possums sometimes play dead- if they’re being threatened by a predator they play dead to escape attack. This increases their chance of survival
Scorpions dance before mating- this makes sure they attract a mate of the same species increasing the likelihood of successful mating

112
Q

Physiological adaptations

A

Processes inside an organism’s body that increase its chance of survival

113
Q

Physiological adaptation?

A

Brown bears hibernate- they lower their rate of metabolism (all chemical reacting taking place in their body) over winter. This conserves energy so they don’t need to look for food in the months when it’s scarce increasing their chance of survival
Sins bacteria- produce antibiotics- these kill other species of bacteria in the area meaning there’s less competition so they’re more likely to survive

114
Q

Anatomical adaptations

A

Structural features of an organism’s body that increases its chance of survival

115
Q

Anatomical adaptations example?

A

Otters have streamlined shape- making it easier to glide through the water making it easier for them to catch prey and escape predators increasing chance of survival
Whales have a thick layer of blubber which helps them keep warm in cold seas increasing their chance of survival in places where food is found

116
Q

Organisms from different taxonomic may have?

A

Similar features even through they’re not closely related e.g. Whales and sharks

117
Q

Why does this happen?

A

Usually because the organisms have evolved in similar environment and to fill ecological niches

118
Q

What’s an ecological niche?

A

The role of an organism within a habitat e.g. What it eats, and when and where it feeds

119
Q

How many different groups of mammals are there?

A

Three

120
Q

What are most mammals?

A

Placental mammals while some are marsupials (and a very few are egg-laying monotremes

121
Q

Where are marsupials found?

A

Mainly in Australia and the Americas

122
Q

When did Marsupial mammals diverge from placental mammals?

A

Many millions of years ago and have been evolving separately ever since

123
Q

Marsupial mammals?

A

Have a short gestation period
Don’t develop a full placenta
Are born early in their development and climb into their mother’s pouch. Here they become attached to a test and recurve milk while they continue to develop

124
Q

Example of marsupial mammal?

A

Kangaroos

125
Q

Placental mammals

A

Long gestation periods
Develop placenta during pregnancy which allows exchange of nutrients and waste products between fetus and mother
Born fully developed
E.g. Humans

126
Q

Are marsupial moles and placental moles related?

A

Not closely they evolved independently on different continents

127
Q

What’s convergent evolution?

A

When two species evolve similar characteristics independently of one and other because they’re adapted to live in similar environments

128
Q

Marsupial moles and placental moles are similar how?

A

Similar anatomical features because they’re both evolved to live in similar environments

129
Q

Describe how marsupial and placental moles environment is similar?

A

Live in tunnels underground

Burrow to reach good supply (earthworms, insects and other invertebrates)

Biology A Level (26 decks)

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