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Classification Flashcards

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1
Q

What is classification?

A

The grouping of organisms into groups based on shared similar characteristics

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2
Q

Why is classification essential?

A

Because there are too many different living things to sort and compare unless they are placed into manageable categories.
It’s flexible to allow newly discovered organisms to be added where they best fit.
It is also able to accommodate fossil organisms as discovered as scientists think living and extinct species are related.

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3
Q

What 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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4
Q

What does a classification system allow?

A

Species to be identified correctly, and allow characteristics to be predicted

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5
Q

What do taxonomists do?

A

Study the differences and similarities between organisms in order to place them into different groups called taxa

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6
Q

What are taxa?

A

Groups that taxonomists place organisms into
E.g phylem
Species
Family
Genus
Etc
When placed into a taxanomic hierarchy they are each knows as a taxanomic rank

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7
Q

What is taxonomy?

A

The study of taxa, placing groups in a taxonomic hierarchy

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8
Q

What is the classification of humans?

A

Domain = eukaryotic
Kingdom = Animalia
Phylum = Chordata
Class = Mammalia
Order = Primates
Family = Hominidae
Genus = Homo
Species = Sapiens

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9
Q

What is the naming system used for classification?

A

Binomial system

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10
Q

What is the binomial system?

A

A naming system for classification that gives all organisms one internationally accepted name in Latin.

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11
Q

What is the species concept?

A

The concept that organisms of the same species have:
-Common ancestors
-Common genes
-Share the same or similar physical, biochemical or behavioural characteristics
-Occupy the same niche (habitat)
-Can Interbreed to produce fertile offspring

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12
Q

What are some problems encountered when defining a species?

A

-Not Al organisms reproduce sexually
-Sexual reproduction can not always be observed so can’t be confirmed
-Definition is not applicable to plants and bacteria as they freely form hybrids and generation after generation some of these my gain fertility

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13
Q

How is a name made using the binomial system of nomenclature?

A

The first name is always capitalised and refers to the genus.
The second name always begin with a small letter and refers to the species.
Both are always written in italics when typed, and underlined when hand written

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14
Q

What do closely related organisms have?

A

The same generic name (only the species name will be different)

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15
Q

Who was the first scientist to arrange a hierarchical system.

A

Linnaeus

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16
Q

What are the taxanomic ranks?

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

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17
Q

What are the five kingdoms?

A

Prokaryotic
Protoctista
Fungi
Plantae
Animalia

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18
Q

What is the protoctista kingdom?

A

Have a nuclear envelope
Uni and multicellular
Cellulose cell wall
Autotrophic and hetrotrophic
No nervous coordination
E.g algae, protozoa

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19
Q

What is the prokaryotic kingdom?

A

Mostly unicellular
No nuclear envelope
Cell wall of peptidoglycan
No visible feeding method
No nervous coordination
Less than 5 micrometres

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20
Q

What is the fungi kingdom

A

Have a nuclear envelope
Multi and unicellular
Cell wall of chitin
Sacrophitic feeding
No nervous coordination

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21
Q

What is the plantea kingdom?

A

Have a nuclear envelope
Multicellular
Cellulose cell wall
Autotrophic feeding
No nervous coordination
Store food as starch

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22
Q

What is the animalia kingdom?

A

Have a nuclear envelope
Multicellular
No cell wall
Hetrotrophic feeding
Have nervous coordination
Store food as glycogen

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23
Q

What is phylogeny?

A

The study of how closely different species are related and reflect the evolutionary relationships. It aims to classify organisms based on their evolutionary relationships.
These are shown using phylogenetic trees

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24
Q

How do phylogenetic trees work?

A

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

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25
What are homologous features?
Features that are shared and have derived from a common ancestor. They may have adapted for different purposes in different organisms but have the same underlying structure and genetic basis.
26
What is an example of a homologous feature?
A pentadactyl limb which includes whale fins, bat wings, and human hands
27
What are the positives of phylegony?
-Produces a continuous tree not taxonomical groups -Avoids the idea that different groups at the same point in the hierarchy are equivalent
28
What did early classification systems use?
Observable features (Anatomical or behavioural)
29
What are classification systems now based on?
Observable features and other evidence that tells us how closely related organisms are.
30
What has the 5 kingdom classification system now been replaced with?
The three domain system
31
Explain how the kingdoms are separated in the three domain system
The prokaryotic kingdom is separated into the archaea and bacteria domains. The other kingdoms were placed into the eukarya domain.
32
What are extremophiles?
Prokaryotes found in extreme environments such as salt lakes, hot springs and alkaline conditions
33
Who introduced what new taxanomic rank?
Woese introduced a new taxanomic rank called the domain
34
How were extremophiles classified in the domains.
They were always part of the archaea domain, however other organisms apart from extremephiles have been known to fit into this group.
35
What does the three domain system propose?
That a common ancestor cell gave way to the three domains
36
How can cytochrome C be used as molecular evidence?
Cytochrome C can be used to see how closely related species are. It is a protein involved in respiration. The more similar the sequence of amino acids are in the protein, the more closely related they are.
37
How can DNA be used as molecular evidence?
The more changes in the sequence of amino acids between organisms, the less closely related they are
38
What are the characteristics of the bacteria domain?
No nucleus No membrane bound organelles Cellnwall of peptidoglycan Circular DNA 1 type of RNA polymerase Sensitive to streptomycin (antibiotic) Has no non coding sequences
39
What are the characteristics of the Archaea domain?
No nucleus No membrane bound organelles No cell wall of peptidoglycan Circular DNA Several types of RNA polymerase Not sensitive to streptomycin Has non coding sequences
40
What are the characteristics of the eukaryote domain?
Has a nucleus and membrane bound organelles No cell wall of peptidoglycan Linear DNA Several types of RNA polymerase Not sensitive to streptomycin Has non coding sequences
41
What does Archaea have
Share characteristics between prokaryotes and eukaryotes
42
Define evolution
The process of how organisms change over time and continue to change. This occurs by the process of natural selection
43
What did Darwin theory rest on?
The idea that organisms show variation and this variation exists even within a single species
44
What are the influences on variation?
Environmental factors are caused by differences in the environment that species live in Genetic factors are caused by genes. Individuals of the same species have the same genes, but different alleles. These alleles make up the genotype, which then makes up the phenotype (displayed characteristics)
45
What is intraspecific variation?
Variation within a species
46
What is interspecific variation?
Variation between different species
47
What is continuous variation?
When individuals in a population vary between two extremes, with many intermediates. These features are usually polygenic and are usually significantly affected by the environment. This is represented as a histogram, where the bars touch
48
What are some examples of continuous variation?
-Milk yields in cows -Mass -Height
49
What is discontinuous variation?
Features that show this variation will show discrete categories. They are usually but not always affected bya single gene and are not usually affected by the environment This is represented by a bar graph
50
What are some examples of discontinuous variation?
-Blood group -Plant colour -Antibiotic resistance
51
Hoe do you work out frequency density on a histogram?
Frequency ÷ class width
52
What is standard deviation?
The variation of data around a mean. It is a measure of spread and gives the likely reliability of the mean value. It is often a more useful measure of dispersion than single ranges as it is not so affected by outliers
53
What are the parts to calculate standard deviation?
x refers to each value in the data set X̌ refers to the mean n is the number of values measured Z is the sum
54
Why do we divide by n-1 when calculating standard deviation?
Because normally we only have data for a sample of organisms so the dispersal is likely to be higher in the whole population
55
What is a normal distribution curve?
Where the distribution of values is symmetrical about the mean, creating a bell shaped graph
56
How is standard deviation used in graphs?
The standard deviation tells you how much the values in a single sample vary. If the standard deviation is 3 and the mean is 9, it means that most of the values will be spread between 6 and 12
57
What is stabilising selection?
Where a species has evolved and removed extreme variations. The standard deviation will be less after the selection pressure that has caused the evolution. This means favourable characteristics are more common, and they are in a stable environment
58
What is directional selection?
This is where there is a shift in the allele frequency caused by evolution due to a change kn the environment e.g climate change. This causes the normal distribution curve to shift side to side but not change shape
59
What is disruptive selection?
This is very rare. This is when a selection pressure causes a split between two extremes, where the extremes are selected for and more than 1 allele is favoured. This maintains polymorphism (multiple alleles in a gene pool) This is caused by a change in the environment
60
What is an adaptation?
A feature that helps an organism to survive and be successful
61
What are anatomical adaptations?
Physical features that dont change quickly. This helps increase an organisms chance of survival. E.g otters have a streamlined shape making it easier for them to glide through the water
62
What are physiological adaptions?
Processes that occur within an organism that increases its chance of survival. E.g a snake producing venom E.g fungi producing antibiotics
63
What are behavioural adaptations?
The way that an organism acts that increase its chance of survival. These can be inherited or learnt E.g earthworms retreating underground when sensing vibrations E.g possums playing dead near predators
64
What are selection pressures?
Pressures that determine the relative success and spread of alleles in a gene pool.
65
What are some examples of selection pressures?
-Finding food -Finding water -Defence -Disease -Other changes (E.g light and temp)n
66
What is a gene pool?
The total number of alleles in a population. Allele frequency may be increased if it is advantageous
67
What is convergent evolution?
The process by which unrelated or distantly related organisms evolve similar body forms, coloration, organs, and adaptations. Shared features which have the same function but different genetic origin are known as analogous structures
68
What are analogous structures?
Shared features which have the same function but a different genetic origin
69
What are marsupial mammals?
Begin life in the uterus but leave to enter the marsupial pouch while they still qualify as an embryo. There, they continue development and attach to the teat and suckle milk. -They have a short gestation period -Don't develop fully in the placenta -Born early in their development
70
What are placental mammals?
The placenta connects to the growing embryo within the uterus to the mothers circulatory system. This provides nourishment and allows the fetus to reach high levels of development before birth. -Have a long gestation period -Are born fully developed -Develop a placenta
71
What have the two classes of mammals done?
Adapted in similar ways to a particular food supply or niche, even if they don't share a common ancestor
72
Where do marsupial mammals live?
Marsupials live mainly in Australia and Europe
73
What were Darwins observations?
1) There is more offspring produced than can survive 2) Yet populations remain relatively stable 3) Characteristics are heritable 4) There was variation withing a population
74
What did Darwin write to explain his observations?
The theory of natural selection
75
What was the 3 deductions that argued for the 'origin of species' (Darwins theory of evolution by natural selection)
-There must be a struggle for existence -Some individuals will succeed better in an environment than others. The variants better adapted are more likely to produce fertile offspring -More better adapted variants will be passed onto offspring. The results accumulate as kne generation follows another
76
What is natural selection?
Where selection pressures cause evolution, and an increase in favourable characteristics arise. For this to occur, intraspecific variation must be present, due to mutations, sexual reproduction etc, which bring about new combinations of alleles
77
Who else helped come up with the development of the theory of evolution by natural selection?
Alfred Russel Wallace. He and Darwin published their papers together.
78
What evidence did Darwin have for the theory of natural selection?
1) Similarities: In the phenotypes of organisms 2) Paleontology: Using the fossil record. Comparisons between fossil anatomy. More complex organisms appeared later. This allowed him to see the relationships between living and extinct organisms. (However the fossil record is incomplete) 3) Comparative anatomy: Anatomy shared between organisms e.g a pentydactlye limb from one common ancestor 4) Artificial selection: He was a pigeon collector and could see that different looking offspring were produced
79
What evidence do we have for evolution?
1) The fossil record: Arranging fossils in chronological order, gradual changes in organisms can be observed that provide evidence for evolution. 2) Biological molecules: -The sequence of bases in DNA can be studied and compared -Cytochrome C can be studied for the amino acid sequence 3) Comparative anatomy: Homologous features can be studied. For example seemingly different featured can be studied to show they acctuly share the same basic structure due to common ancestory. This is an example of divergent evolution.
80
What is fossilization?
It is rare and is where fossils remain due to lack of microbes, water, oxygen and warmth. These are found in sedimentary rock, where sediment has deposited over time
81
What does bacteria have?
Very short generation times, especially in optimum conditions, by reproducing asexually, but are capable of exchanging genes with each other in the form of plasmids.
82
What has widespread use of antibiotics caused?
Widespread antibiotic resistance
83
What is a pest?
An organism that is in competition with humans for food or space, and is generally hazardous to health
84
What are the implications of pesticide resistance?
Crop infestations are harder to control Some insects are resistant to lots of pesticides Yield may decrease Broader pesticides may have to be used which could kill more helpful pests New pesticides may have be be produced which takes time and money
85
What is speciation?
The appearance of a new species from a pre existing one over multiple generations. This is because they are no longer able to reproduce with the original species to produce fertile offspring. This is caused by a reproductive barrier: Either allopatric or sympatric speciation
86
What is allopatric speciation?
This is caused by a geographical barrier where species evolve in two or more areas.
87
What is sympatric speciation?
Where organisms are still all living in the same place but there has been a biochemical change, causing the species to not recognise eachtoher as the same species

Biology (14 decks)

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