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a level biology > Classification > Flashcards

Classification Flashcards

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1
Q

Classification

A
  • the name given to the process by which living organisms are sorted into groups
  • the organisms within each group share similar features
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2
Q

Taxonomic groups

A
  • the hierarchal groups of classification
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3
Q

what are the taxonomic groups

A
  • kingdom
  • phylum
  • class
  • order
  • family
  • genus
  • species
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4
Q

kingdom

A
  • biggest and broadest taxonomic group
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5
Q

species

A
  • smallest and most specific classification
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6
Q

Linnaean classification

A
  • hierarchal classification system
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7
Q

which level of classification was added

A
  • domain
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8
Q

Domain

A
  • top of the classification hierarchy
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9
Q

why do scientists need to classify organisms

A
  • to identify species
  • predict characteristics
  • find evolutionary links
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10
Q

identifying species

A
  • by using a clearly defined system of classification
  • the species an organism belongs to can be easily identified
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11
Q

predict characteristics

A
  • if several members in a group have a specific characteristic
  • it is likely another species in the group will have the same
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12
Q

finding evolutionary links

A
  • species in the same group
  • share characteristics
  • as they have evolved from a common ancestor
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13
Q

why is using a single classification important

A
  • scientists can share their research
  • links can be seen even if they live on different continents
  • universal language scientists from all over the globe can understand
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14
Q

why have classification systems been created

A
  • to order observed organisms
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15
Q

how are the organisms initially classified

A
  • by separating organisms into the 3 domains
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16
Q

3 domains

A
  • archaea
  • bacteria
  • eukarya
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17
Q

as you move down the classification system what happens

A
  • there are more groups at each level
  • fewer organisms in each group
  • organisms in each group become more similar / share more similar characteristics
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18
Q

what is the last level organisms are classified into

A
  • individual species
  • smallest units of classification
  • only contains one type of organism
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19
Q

species - definition

A
  • a group of organisms that are able to reproduce to produce fertile offspring
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20
Q

when a horse is bred with a donkey, mules or hinnys are produced - why aren’t these classed as species

A
  • infertile
  • cells contain an odd number of chromosomes
  • therefore meiosis and gamete production cannot take place correctly as all chromosomes must pair up
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21
Q

human species

A

homo sapiens

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22
Q

why is naming organisms by their physical characteristics useful

A
  • working with scientists internationally
  • organisms may have more than 1 common name
  • different names in different languages
  • common names do not provide information about the relationships between organisms
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23
Q

binomial nomenclature

A
  • to ensure scientists internationally are discussing the same organism
  • this system was developed
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24
Q

what are the 2 parts of a species scientific name

A
  • first word indicates organisms genus / generic name
  • second word indicates organisms species / specific name
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25
how do we write the name of an organism
- upper case letter for the first letter of the genus - otherwise all in lowercase
26
how many kingdoms
5
27
5 kingdoms
- prokaryotae (bacteria) - protoctista (unicellular eukaryotes) - fungi - plantae - animalia
28
prokaryotae
- unicellular - no nucleus - no membrane bound organelles - small ribosomes - a ring of 'naked' DNA - no visible feeding mechanism - nutrients absorbed by cell wall / produced by photosynthesis internally
29
protoctista
- mainly unicellular - a nucleus - membrane bound organelles - some have chloroplasts - some sessile - some move by cilia, flagella - nutrients acquired by photosynthesis or - ingestion of other organisms
30
example of prokaryotae
- e coli
31
example of protoctista
- amoeba
32
fungi
- unicellular/multicellular - nucleus - membrane bound organelles - cell wall made of chitin - no chloroplasts/chlorophyll - no mechanisms for locomotion - most have a body or mycelium made of threads/hyphae - nutrients acquired by absorption - most store their food as glycogen
33
how are nutrients acquired by absorption in fungi
- decaying material - fungi are saprophytic feeders - some fungi are parasitic
34
fungi examples
- yeast - mushrooms - moulds
35
plantae
- multicellular - nucleus - membrane bound organelles - chloroplasts - cellulose cell wall - chlorophyll - most do not move - nutrients acquired by photosynthesis - stores food as starch
36
plantae are autrophic feeders, what is this
- they make their own food
37
example of plantae
- flowering plants - roses - oak trees - grasses
38
how many plantae species
over 250,000
39
animalia
- multicellular - nucleus - membrane bound organelles - no cell walls - no chloroplasts - move with aid of cilia, flagella or contractile proteins - nutrients acquired by ingestion = heterotrophic feeders - food stored as glycogen
40
how many animalia
over 1 million
41
animalia examples
- mammals, e.g cats - reptiles, e.g lizards
42
why are classification systems changing
- through the study of genetics and biological molecules - evolutionary relationships between organisms can be studied
43
what happens when organisms evolve to their genetics
- DNA changes - this determines the proteins which are made - determining organisms characteristics - which is why external and internal features may change
44
how can scientists discover evolutionary relationships
- by comparing the similarities in DNA - and proteins of different species
45
how does haemoglobin indicate a common ancestry between different primate groups
- haemoglobin in humans differs from chimpanzees in only 1 amino acid - humans differ from gorillas in 3 amino acids - humans differ from gibbons in 8 amino acids - overall structure is the similar between organisms
46
haemoglobin structure
- protein - 4 polypeptide chains - each chain is made up of a fixed number of amino acids
47
what are the 3 domains
- archaea - bacteria - eukarya
48
what are the differences between the 3 domains
- unique form of rRNA - different ribosomes
49
Eukarya
- 80 s ribosomes - RNA polymerase (12 proteins) -
50
RNA polymerase
- responsible for most mRNA transcription
51
Archaea
- 70 s ribosomes - RNA polymerase of different organisms - 8-10 proteins - similar to eukaryotic ribosome
52
Bacteria
- 70 s ribosomes - RNA polymerase ( 5 proteins)
53
Bacteria - kingdoms
- eubacteria
54
Archaea - kingdoms
- archaebacteria
55
Eukarya - kingdoms
- protoctista - plantae - animalia - fungi
56
Prokaryotae kingdoms
- eubacteria - archaebacteria
57
why is eubacteria and archaebacteria classified into their own kingdoms
- different chemical makeup - eubacteria contains peptidoglycan in their cell wall wheras archaebacteria do not
58
Archaebacteria
- lives in extreme environments - e.g hot thermal vents - e.g anaerobic conditions
59
eubacteria
- true bacteria - found in all environments - most bacteria
60
phylogeny
- the name given to evolutionary relationships between organisms
61
phylogenetics
- the study of evolutionary history of groups of organisms - it reveals which group an organism is related to - how closely related these organisms are
62
phylogenetic trees
- diagram used to represent evolutionary relationships between organisms - branched diagrams - they show that different species have evolved from a common ancestor
63
Structure pf phylogenetic trees
- earliest species at the base of the tree - most recent species are found at tips of branches
64
how are phylogenetic trees produced
- looking at similarities and differences in species physical characteristics and genetic makeup
65
advantages of phylogenetic classification
- confirms classification groups are correct - can be done without reference to Linnaean classification - produces a continuous tree - Linnaean classification can be misleading
66
Phylogeny produces a continuous tree-
- better because classification requires discrete taxonomical groups - scientists are not forced to put organisms into a specific group that they do not fit
67
linnean classification system can be misleading
- it implies different groups within the same rank are equivalent
68
Darwin - theory
- theory of evolution
69
evolution
- theory that describes the way in which organisms change over many years - due to natural selection
70
Theory of evolution
- organisms best suited their environment are more likely to survive and reproduce - passing on characteristics onto offspring - gradually a species changes over time - giving a more advantageous phenotype for the environment in which it lives - advantageous characteristics are passed onto 1 generation to the next - by genes in DNA molecules - slow process - small changes gradually accumulate over time
71
Observations - Darwin
- HMS beagle = Galapagos islands - finches - pigeons = England
72
Issues with the theories of evolution and natural selection
- conflicted with religious view that God had created all of the animals and plants on Earth - suggests humans are evolved from apes - conflicted with belief that God created man in his own image
73
Evidence for evolution
- palaontology - comparative anatomy - comparative biochemistry
74
palaeontology
- study of fossils - and the fossil record
75
comparative anatomy
- study of similarities and differences - between organisms anatomy
76
comparative biochemistry
- similarities and differences - between chemical makeup of organisms
77
how are fossils formed
- when plant and animal remains are preserved in rocks - sediment is deposited on the Earth to form layers of rock
78
what do the different layers of rock formed from fossils correspond to
- different geological eras - most recent layer found on the top
79
fossil record
- within the rock strata different fossils are found - a sequence from oldest to youngest is found in rock strata - showing how organisms gradually change over time
80
evidence for fossil record
- fossils of simplest organisms like bacteria are found in the oldest rocks - sequence in which organisms are found matches their ecological links to each other - by studying similarities in anatomy of fossil organisms scientists can show how closely related organisms have evolved from the same ancestor - allow relationships between extinct and living organisms to be investigated
81
why isn't the fossil record complete
- many organisms are soft bodied and decompose quickly - before they have a chance to fossilise - conditions needed for fossils to form are not often present - other fossils may have been destroyed by Earths movements / could be undiscovered
82
comparative anatomy - homologous structure
- structure that appears superficially different in different organisms - but has the same underlying structure
83
example of a homologous structure
- pentadactyl limb of vertebrates
84
vertebrate limbs
- wide variety of functions - running, jumping, flying - basic bone structures of all vertebrate limbs are all similar - bones are just adapted to suit different functions - showing all vertebrates have evolved from a common ancestor
85
what does the presence of homologous structures provide evidence for
- divergent evolution
86
divergent evolution
- how species have evolved from a common ancestor - each with a set of adaptive features
87
when does divergent evolution occur
- when closely related species diversity will adapt to new habitats - as a result of migration or loss of habitat
88
comparative biochemistry - most common molecules studied
- cytochrome
89
cytochrome
- a protein - involved in respiration - involved in ribosomal RNA
90
how can comparative biochemistry be used to discover how closely species are related
- molecular sequence of a particular molecule is compared
91
in comparative biochemistry what information can scientists gather
- the point at which the 2 species last shared a common ancestor - species that are closely related have more similar DNA and proteins - those distantly related have fewer similarities - rRNA is commonly used with fossil information to determine relationship between ancient species
92
variations
- differences in characteristics between organisms
93
interspecific variation
- widest type of variation is between members of different species
94
intraspecific variation
- differences between organisms within a species
95
2 causes of variation
- an organisms genetic material = differences in the genetic material an organism inherits from its parents - the environment in which the organism lives
96
2 types of variation
- genetic - environmental
97
genetic variation causes
- due to genes (alleles) an individual possesses
98
genetic causes of variation
- alleles - mutations - meiosis - sexual reproduction - chance
99

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