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Classification And Evolution Flashcards

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1
Q

What is classification?

A

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

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2
Q

What is taxanomy?

A

Where taxanomists study the similarities and differences between organisms in order to place them into groups called taxa, then into a taxanomic hierarchy.

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3
Q

What are the different taxanomic groups?

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

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4
Q

What is the classification of humans?

A

Eukarya, animalia, chordata, mammalia, primates, hominidae, homo, sapiens

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5
Q

What do organisms of the same species have?

A

-A common ancestor
-Share the same morphological, physiological, biochemical and behavioural characteristics
-Occupy the same niche
-Can Interbreed to produce fertile offspring

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6
Q

What us the naming system we use?

A

The binomial system of nomenclature

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7
Q

What is the binomial system?

A

A way of naming species. The first name has a capitalised first letter and is the Genus. The second name always begins with a smaller letter and is the species. Both are written in italics, but underlined when written by hand.

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8
Q

What do closely related organisms have?

A

The same generic name, only the species name differs

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9
Q

What are some problems encountered when defining species?

A

-Not all organisms reproduce sexually
-Sexual reproduction van not always be observed

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10
Q

Why do we classify things?

A

Because there are too many living things to sort out and compare unless they are out in manageable catagories

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11
Q

What does the scheme of classification have to be?

A

Flexible to fit new organisms if discovered. It should also be able to accommodate fossil species as they are discovered as biologists belive that living and extinct species are related

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12
Q

Wjat does the process of classification involve?

A

-Giving every organism an agreed name
-Arrangement of organisms into groupings of apparently related organisms

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13
Q

What is hierarchical classification?

A

It ranks groups in ascending order from large to small groups. Each group is known as a taxanomic rank.

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14
Q

Who was the first person to devise a heirachcal system?

A

Linnaeus who used 7 taxanomic ranks

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15
Q

What is the kingdom prokaryotae?

A

Bacteria is an example. Unicellular cells, less than 5 micrometres. Have no nucleus. Cell walls made of peptidoglycan. Has mobility. No membrane bound organelles

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16
Q

What is the protoctista kingdom?

A

Examples are algae, protozoa. Eukaryotic cells usually living in water. Either single celled or simple multicellular organisms. They sometimes have a cell wall of cellulose. Use autotrophic and hetrotrophic nutrition. Sometimes mobile.

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17
Q

Wjat is the fungi kingdom?

A

Examples are mould, yeast, mushrooms. Eukaryotic cells with chitin cell walls. Use saprotrophic feeding. Single celled or multi celled organisms

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18
Q

What is the plantae kingdom?

A

Examples are mosses, ferns and flowering plants. Eukaryotic cells. Multicellular organisms. Cell walls of cellulose and use autotrophic feeding. They store their food as starch

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19
Q

What is the animalia kingdom?

A

Examples are nematodes, insects and reptiles. Eukaryotic cells. Multicellular with no cell walls. Use hetrotropjic feeding. They are ablento move and have nervous coordination. They store food as glycogen.

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20
Q

What is phylegony?

A

The study of evolutionary relationships, aiming to classify them. These are shows using phylogenetic trees.

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21
Q

Explain phylogenetic trees

A

The closer together organisms are on the tree, the closer related they are. The distance between branch points represents the amount of time between divergence

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22
Q

What is a species according to phylogenetics?

A

The smallest group that shares a common ancestor.

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23
Q

What did classification used to be based on?

A

Observable features

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24
Q

What are homologous features?

A

Features that are shared and have derived from a common ancestor

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25
What is an example of a homologous feature?
The pentydactyl limb
26
What does a phylogenetic tree do that other classification systems don't?
-Produces a continuous tree not taxanomical groups -Avoids the idea that different groups at the same point in the heirachy are equal
27
What evidence do we use now for classification?
-Observable features -Paleontology -Molecular evidence E.g cytochrome C, amino acids, DNA
28
What evidence did Darwin have for natural selection?
-Comparative anatomy -Paleontology -Artificial selection (Using his pigeon selection)
29
What has the 5 kingdoms system now been replaced with?
The 3 domains system
30
What are the is the kingdom prokaryotae split into for domains?
Archae and bacteria
31
What are the 3 domains?
Archae, eukarya, bacteria
32
What are exremophiles?
Prokaryotes found in extreme environments. This is why prokaryotes are not split into 2 domains
33
Who introduced the taxanomic rank domain?
Woese
34
What group are extremophiles places in?
Archae
35
What components make up the bacteria domain?
No nucleus or membrane bound organelles. Has a cell wall of peptidoglycan. DNA is circular and there is only 1 type of RNA polymerase. There are non non coding sequences within genes
36
What components make up the archae domain?
Has no nucleus or membrane bound organelles. No cell wall of peptidoglycan. Has circular DNA bit several types of DNA. It has non coding sequences within genes
37
What co potential make up the eukaryote domain?
Has a nucleus and membrane bound organelles. Has no cell wall of peptidoglycan. Has linear DNA in the nucleus and several types of RNA. There are non coding sequences within genes
38
What evidence was there to introduce the three domain system?
-Biochemistry -Molecular evidence: RNA polymerase is different in bacteria and archae. Archae has similar histories to eukarya -Cellular evidence: The bonds of lipids are different in bacteria and archae Have different compositions of flagella
39
What are archae more closely related to?
The eukarya domain
40
What is variation?
The differences that exist between individuals
41
What is intraspecific variation?
Variation within a species
42
What is interspecific variation?
Variation between different species
43
What is continuous variation?
Features that show a range of phenotypes between two extremes with many intermediate. These are usually controlled by more than one gene (polygenic) and are usually significantly affected by the environment.
44
What is continuous variation shown as?
-Usually by a histogram -The bars always touch It usually shows a typical bell shaped normal distribution curve
45
How do you work out the frequency density on a histogram?
If one of the class widths are larger e.g one of them is 19 but the rest is 5, we work out the frequency density per 5. We do all the other rows normally, but for the 10mm one we divide by 2 instead (because 10/5 is 2) Frequency density = frequency ÷ class width
46
What is discontinuous variation?
Features in discrete catagories. They are usually but not always affected by a single gene and are not usually affected by the environment. The bars do not touch on a graph
47
What are genetic causes of variation?
Individuals of the same species have the same genes but different alleles. The alleles make up its genotype. The differences in genotypes make up their phenotypes
48
What are environmental causes of variation?
E.g climate, food, lifestyle
49
What is standard deviation and what does it show us?
It is the variation of data around the mean. It gives an indication of the reliability of the mean value. It is less affected by outliers.
50
What is a normal distribution curve?
Where there is a bell shaped curve, that is symmetrical about the mean.
51
Explain standard deviation
If it is 3, and the mean is 9, it means most of the values will be between 6 and 12.
52
What is the calculation for standard deviation?
_/Z(x-x̌)²÷n-1 x = each value in a data set X̌ = the mean n = the number of values measured
53
What is an adaptation?
A feature that helps an organism survive and be successful
54
What are behavioural adaptations?
The way an organism acts to increase its chance of survival. E.g earthworms will retreat undergroundwhen touched or sense vibrations
55
What are physiological adaptions?
The processes inside an organism that increase its chance of survival. E.g brown bears will hibernate. They lower their metabolic rate over winter to conserve energy so they don't have to look for food when it's scarce E.g some bacteria produce antibiotics
56
What are atomical adaptions?
Structural features of an organisms body that increases its chance of survival. E.g otters have a streamlined shape making it easier for them to glide through the water making it easier for them to catch prey Emg whales have a thick layer of blubber
57
What is a selection pressure?
Pressures that make it difficult to survive. They determine the relative success and spread of alleles in a gene pool. R.g food, water, space etc.
58
What is convergent evolution?
The process by which unrelated organisms evolve similar body forms, colouration and organs. They have the same function but different genetic origin. These are known as analogous features
59
What are marsupials?
Found in Australia and America. They diverged from placentals. They have a short gestation period and don't fully develop in the placenta. They are born earlier and climb into the mothers pouch to attach to the teat and receive milk while they fully develop
60
What are placental mammals?
They have a longer gestation period and develop fully in the placenta.
61
What is fossialisation?
A rare event. Only occurs in the absence of microbes. They can be found in sedimentary rocks where sediment deposits over time. It is an example of evidence for natural selection.
62
What is divergent evolution?
Where species with a shared common acmncestor continue to evolve becoming increasingly different
63
What were darwins observations?
-Organisms produce more offspring than survive -There is variation within a species -Some characteristics are passes on from one generation to the next -Individuals that are best adapted are more likely to survive
64
What were the deductions that Darwin made?
-There must be a struggle for existence in which some die -Some variants will succeed better than others. The variants better adapted will be more likely to survive -The better adapted variants will reproduce and pass on their alleles to their offspring causing a species to gradually change
65
What is an example of natural selection?
Peppered moths before and during the industrial revolution where the pollution had blackened many trees
66
Who else helped Darwin with the theory of evolution by natural selection?
Wallace
67
What evidence I'd there for natural selection?
-Fossil record -Molecular evidence
68
What are pesticides?
Chemicals that kill pests
69
What are the implications of pesticide resistance?
-Crop infections are harder to control -Takes a while to figure out what other pesticide to use -May have to use broader pesticides which could kill beneficial insects -Spread of disease may increase -Expencive to make new pesticides
70
What are the implication of drug resistance?
Infections are harder to treat Takes a while to figure out what other medicidmne to use Costs money to develop new ones
71
What is speciation?
The apparently of a new species from a pre existing one over multiple generations. The species are no longer able to breed with the original species and produce fertile offspring
72
What is geographical speciation?
Also called allopatric. Where species evolve in two or more areas with different selection pressures
73
What is sympatric speciation?
Where they still live in the same area but have a reproductive barrier. This is either because of a biochemical change or because they don't recognise each other as the same.
74
What is stabilising selection?
When favourable characteristics become more common. This happens in a stable environment when the standard deviation decreases
75
What is directional selection?
This is in e.g climate change, where the favourable alleles shift, causing a change in the most common alleles.
76
What is disruptive selection?
This is the most rare. There is a split between two extremes and a dip in the middle. This maintains polymorphism.
77
What is the system called that now takes into account phylogeny when arranging organisms into groups?
Cladistics
Biology OCR
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