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BIOLOGY A LEVEL > CHAPTER 10 - CLASSIFICATION AND EVOLUTION > Flashcards

CHAPTER 10 - CLASSIFICATION AND EVOLUTION Flashcards

1
Q

What are the 7 taxonomic groups (linnaean classification)

A

Kingdom, Phylum, Class, Order, Family, Genus, Species
(Ellis method)

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2
Q

Why do scientists classify organisms

A

To identify species
To predict characteristics
Find evolutionary links

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3
Q

What is a species defined as

A

A group of organisms that are able to reproduce to produce fertile offspring

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4
Q

State two reasons why classification is important

A

Enables scientists to share information / makes communication easy

provides information about an organism, based on members of the same group

allows accurate identification of an organism

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5
Q

Ligers are the offsprings of male lions and female tigers. Suggest two reasons why ligers are not classified as a species but their parents are

A

Ligers cannot reproduce to produce more ligers therefore they are not a species

Both lions and tigers reproduce to produce fertile offspring, therefore they are species

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6
Q

The loganberry (Rubus loganobaccus) is the fertile offspring of the blackberry (Rubus ursinus) and the raspberry (Rubus idaeus). Explain why the Loganberry is difficult to classify into a taxonomic group

A

Both parents are members of the same genus (Rubus)

but different species (ursinus and idaeus)

Two different species cannot produce fertile offspring / according to the taxonomic classification system the loganberry should not be fertile

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7
Q

What are the general features of prokaryotae

A

Unicellular
No nucleus or membrane mound organelles
Rings of ‘naked’ DNA
Small ribosomes
No visible feeding mechanism

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8
Q

What are the general features of protoctista

A

Mainly unicellular

Nucleus and other membrane bound organelles

Some contain chloroplasts

Some can move using flagella, cilia or amoeboid mechanisms but others are sessile

Nutrients acquired by photosynthesis

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9
Q

What are the general features of fungi

A

Unicellular or multicellular

A nucleus and other membrane bound organelles, with a chitin cell wall

No chloroplasts

No mechanism for locomotion

Most have a body or mycelium made up of threads or hyphae

Saprophytic - absorb decaying material

Store food as glycogen

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10
Q

What are the general features of plantae

A

Multicellular

A nucleus and other membrane-bound organelles including chloroplasts

All contain chlorophyll

Most dont move, although gametes of some plants move using cilia or flagella

Autotrophic - organisms make their own food

Store food as starch

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11
Q

What are the general features of Animalia

A

Multicellular

Nucleus and other membrane bound organelles

No cell wall

No chlorplasts

Move with aid of cilia, flagella or contractile proteins (eg. muscular organs)

Heterotrophic - ingest food

Food stored as glycogen

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12
Q

State two differences between fungi and plants

A

Plants have chloroplasts / chlorophyll, whereas fungi do not

plants are autotrophs, whereas fungi are heterotrophs

fungi may be unicellular, plants are always multicellular

fungi store food as glycogen, whereas plants store food as starch

plant cell walls are composed of cellulose, whereas fungi cell walls are composed of chitin

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13
Q

Explain why prokaryotes are now classified as two separate domains

A

Advances in biological techniques have identifies large differences in composition

ribosomes/rRNA differ

cell walls differ – peptidoglycan not found in archaea

Old classification does not show correct phylogeny

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14
Q

What are the three systems of classifying

A

3 domain system
6 kingdom system
5 kingdom system
(pg 239)

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15
Q

Explain why prokaryotes are now classified as two separate domains

A

Advances in biological techniques have identifies large differences in composition

ribosomes/rRNA differ

cell walls differ – peptidoglycan not found in archaea

old classification does not show correct phylogeny

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16
Q

Describe how and why classification systems have changed over time

A

Living organisms classified into two kingdoms based on major differences in characteristics

for example, those that moved and ate (animals) and those that didn’t (plants)

scientific advances/use of microscope allowed smaller details to be observed

organisms divided into five kingdoms

Plants, animals, fungi, protoctista, prokaryotes

Advances in science allowed DNA and proteins to be studied

Provided evidence for evolutionary relationships

Three domain system proposed

Relevant scientists mentioned (Linnaeus, Whittaker, Woese)

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17
Q

What is phylogeny

A

Evolutionary relationships between organisms

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18
Q

What are some advantages of phylogenetic classification

A

It takes into account evolutionary relationships that might not be obvious by just looking at characteristics

it forms a continuous tree so organisms do not have to be forced into groups

is not hierarchical therefore different groups on the tree are represented according to their evolutionary position – and can thus be compared

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19
Q

State the main difference between early classification systems and systems based on phylogeny

A

Historical classification systems based on physical characteristics / niche occupancy, whereas phylogeny based on evolutionary relationships

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20
Q

What is evolution

A

The way in which organisms evolve or change over many years as a result of natural selection

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21
Q

What evidence is there for evolution

A

Palaeontology and fossil records
Comparative anatomy
Comparative biochemistry

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22
Q

How are fossils formed

A

Animal and plant remains are preserved in rocks,

Time of existence can be determined by amount of rock build up on top

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23
Q

What evidence is provided by the fossil record

A

Timeline, of simpler organisms buried deeper in the rock and more complex higher up

Sequence matches ecological links - eg. plants are found before animals

Anatomy can show how closely related organisms have evolved from the same ancestor eg. zebra/horse and rhino

Allows relationships between extinct and living organisms to be investigated

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24
Q

What is one issue in the fossil record

A

It is incomplete, partly due to soft bodied organisms decomposing before having a chance to fossilise

25
What are homologous structures, what is an example, and how does it show divergent evolution
Structure that appears superficially different (and may perform different functions) in different organisms but has the same underlying structure eg. Pentadactyl limb Evolved form a common ancestor and have to adapt to new habitats
26
What are the two most commonly studied biochemistry molecules in comparing species relationships
Cytochrome c - protein in respiration rRNA - ribosomal RNA
27
What is the hypothesis of neutral evolution
Most of the variability in the structure of a molecule doesn't affect its function
28
Describe what is shown on a phylogenetic tree
A diagram used to show evolutionary relationships between organisms the closer the branches of the tree the closer the evolutionary relationships - meetings of lines are called nodes
29
Describe two advantages and two disadvantages of using the fossil record as a source of evidence for evolution
Advantages: radioisotopes can be used to date fossils changes can be tracked over time chronological order apparent in rock strata. Disadvantages: many organisms decompose quickly before they have a chance to fossilise/ destroyed by volcanoes/ destroyed by earthquakes
30
Describe how the work of three scientists was used in the development of the theory of evolution
Lyell – suggested that fossils were actually evidence of animals that had lived millions of years ago. Hutton – proposed theory of uniformitarianism. Darwin – came up with theory of evolution by natural selection through observations in Galapagos islands / jointly published theory. Wallace – came up with theory of evolution by natural selection in Borneo/jointly published theory
31
Explain how comparative biochemistry provides evidence of evolution
Study of similarities and differences in proteins and nucleic acid/DNA of an organism changes in highly conserved molecules can help identify evolutionary links such as cytochrome C / ribosomal RNA species that are closely related have the most similar DNA and proteins /distantly related have far fewer similarities
32
What is interspecific variation
Variation between members of different species
33
What is infraspecific variation
Differences between organisms within a species
34
What are the factors that cause variation
Differences in the genetic material an organism inherits from its parents leads to genetic variation Environment in which it lives, this causes environmental variation
35
What are the Genetic causes of variation
Differing Alleles Mutations Meiosis - Independent Assortment and Crossing over Sexual reproduction - mix of alleles inherited Chance- many gametes produced by parents
36
What is an example of environmental causes of variation
pH of soil, which causes changes in flower colour
37
Name two human characteristics with variation caused solely by the environment
scar, tattoo, dyed hair
38
Name two human characteristics with variation cause solely by genetics
eye colour, blood group, lobed or lobeless ears
39
Explain some of the causes of variation of human hair
Caused by a combination of genetics and the environment Genes determine the natural colour of hair and texture, e.g. curly/straight Environment affects final appearance, e.g. if hair is cut, dyed, or lightened by sunlight
40
Explain more genetic variation is more common in organisms that reproduce sexually
Individuals produced by asexual reproduction are clones/genetically identical to parents no fertilisation so no mixture of genetic material meiosis does not take place/ no production of gametes DNA can only be altered as a result of mutation
41
What is discontinuous variation
value at either end of a spectrum, no middle value eg. an animal sex either Male or Female or shape of a bacteria
42
What is continuous variation
A characteristic which can take any value within a range eg. weight or height (can be influenced by environmental factors)
43
What types of ways are there of showing variation
Distribution curve Standard deviation T-tests Spearman's rank
44
what are some adaptations
Anatomical adaptations - physical features Behavioural adaptations - The way an organism acts, inherited or learnt from their parents Physiological adaptations - processes that take place inside an organism
45
What are some examples of anatomical adaptations
Body covering - eg. hair, scales, spines, feathers Camouflage Teeth - type of teeth present Mimicry eg. markings of another species
46
What are some adaptations of marram grass
Curled or rolled leaves, to minimise surface area of moist tissue Hairs on the inside surface of leaves to trap moist air Stomata sunk into pits Thick waxy cuticle on the leaves and stems
47
What are some examples of behavioural adaptations
Survival behaviours - eg. rabbit freezing when it has been seen Courtship - dancing etc... Seasonal behaviours - migration and hibernation
48
What categories to behavioural adaptations fall into
Innate behaviour - inherited through genes eg. web building of spiders Learned behaviour - learnt through experience or observing other animals. otters using stones to hammer shells
49
What are some examples of physiological adaptations
Poison production - hunting or protection Antibiotic production - kill off bacteria Water holding - especially in arid environments
50
What are analogous structures, what is an example, and how does it prove convergent evolution
they have adapted to perform the same function but have a different genetic origin Tail fins of whale and a fish perform the same role Takes place when unrelated species begin to share similar traits, adapting to a niche
51
State the difference between analogous and homologous structures
Characteristics which show discontinuous variation are purely controlled by genetics/no environmental influence (except scars/tattoos just environment) Normally controlled by a single gene Characteristics which show continuous variation are controlled by a combination of genetic and environmental causes Controlled by a number of genes/ polygenes
52
Which of the following is an example of convergent evolution, and explain your answer Insect wing and bird wing Bat wing and human arm
Insect and bird wing – both have evolved to fly to escape predators/hunt for food
53
State and explain how marsupial moles and placental moles provide evidence for convergent evolution
They have analogous structures – anatomical features that perform the same function in different organisms, but have a different origin Any two from: Both burrow through soft soil to find insects Both have a streamlined body shape, and modified forelimbs for digging Both have velvety fur which allows smooth movement through the soil
54
What is the process for natural selection
Variation in an organism from mutation occurs Organism whose characteristic best suited to selection pressure will survive and reproduce Successful organisms pass on successful alleles Process repeated for every generation, increasing frequency of successful allele Over a long period, this can lead to an evolution of a new species
55
What are some examples of modern evolution
Antibiotic-resistant bacteria Peppered moths Sheep blowflies Flavobacterium
56
State three selection pressures that may be experienced by a plant species
availability of light / water / nutrients / carbon dioxide / space, risk of being eaten, disease, ability to cross-pollinate
57
Describe the process of natural selection
Variations exist within a population those with the best characteristics survive AND reproduce characteristics are passed onto their offspring through genes
58
DDT is a chemical insecticide that was used to kill mosquitoes to prevent the spread of malaria. Several years after its introduction large populations of mosquitoes became DDT resistant. Explain how this occurred.
A mutation occurred / existed in the mosquitos DNA which made them DDT resistant these organisms survived exposure to DDT and reproduced mutation which caused resistance is passed onto their offspring frequency of the DDT-resistant allele increases in the population
59
Examples state and explain the positive and negative effect on humans of recent examples of evolution in some species
Flavobacterium digests nylon waste positive – used to clean up factory waste bacteria e.g. MRSA – antibiotic resistance negative – no longer killed using current medical treatment sheep blowfly – insecticide resistant negative – no longer killed by insecticide so increased sheep death

BIOLOGY A LEVEL (24 decks)

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