2.1 Flashcards
1
Q
What does phylogenetic mean
A
Evolutionary relatedness
2
Q
What does it mean when organisms are in the same phylogenetic group
A
Have a more recent common ancestor
3
Q
What is LUCA
A
The last universal common ancestor. Earliest branch point of all living things
4
Q
What are taxa
A
Classification groups
5
Q
What do members of the same taxonomic group share
A
Similar characteristics
6
Q
Who devised the classification system today
A
Carl Linnaeus
7
Q
What is taxonomy
A
The identification and naming of organisms
8
Q
What is classification
A
Grouping organisms
9
Q
What is a hierarchy
A
A system of ranking in which small groups are nested components of larger groups
10
Q
What is a taxon
A
Any group within a system of classification.
11
Q
Domain
A
The largest taxonomic group
12
Q
What domain are humans
A
Eukaryotic domain
13
Q
Kingdom
A
- 5 kingdoms.
- Kingdoms contain phyla
14
Q
What kingdom are humans
A
Animal kingdom
15
Q
Phylum
A
- Phylum contain classes
16
Q
What phylum is humans
A
Phylum Chordata (vertebrates)
17
Q
Class
A
- Classes contain orders
- 5 classes of chordates (vertebrates).
18
Q
What are the 5 classes of chordates (vertebrates)
A
Mammals, fish, birds, reptiles, amphibians.
19
Q
Order
A
Orders contain families
20
Q
What order are humans
A
Primate order
21
Q
Family
A
Family contain genera.
22
Q
What family are humans
A
Hominidae family
23
Q
Genus
A
General contain species
24
Q
What genus are humans
A
Homo genus. We are the only remaining members of this genus
25
Species
This taxonomic group contains only one type of organism and all will be closely remated
26
What species are humans
Homo sapiens.
27
What does it mean when taxa are discrete
That an organism can only belong to one taxon at each classification level
28
Why do we need a classification system
-Allows us to infer evolutionary relationships. If two organisms in the same taxon we infer they're closely related.
-If a new animal is discovered with a beak and feathers we can predict some of its other characteristics.
29
What does it mean that our system of classification has a tentative nature
May be altered as our knowledge advances
30
What are the 3 domains
1. Eubacteria
2. Archaea
3. Eukaryota
31
What are eubacteria
Familiar bacteria like E.Coli and Salmonella. Prokaryotes.
32
What are archaea
Bacteria and often have unusual metabolism e.g some generate methane. They live in marginal habitats and are also prokaryotes
33
What are Eukaryota
Includes Plantae, Animalia, Fungi, and Protoctista. All eukaryotic organisms.
34
What is the five-kingdom classification system
Classifies organisms on the basis of their physical appearance because organisms in different kingdoms have major significant differences
35
What kingdom are all bacteria in (eubacteria and archaea
Prokaryota
36
What are the 5 kingdoms
1. Prokaryota.
2. Protoctista.
3. Fungi.
4. Plantae.
5. Animalia.
37
Main features of Prokaryota
- Unicellular and microscopic.
- No membrane bound organelles.
- Cell wall of murein not cellulose
38
Main features of Protoctista
- Single celled.
- Eukaryotic.
- No tissue differentiation.
39
Main features of Fungi
- Heterotrophic (have to consume food).
- Eukaryotic.
- Cell wall of chitin.
- Reproduce by spores
40
Main features of Planta
- Multicellular eukaryotes.
- Photosynthetic.
- Cellulose cell wall.
- Eukaryotic.
41
Main features of Animalia
- Heterotrophic.
- Multicellular.
- No cell wall.
- Nervous coordination.
42
Homologous structures
Have the same structure but a different function e.g. pentadactyl limb.
43
What is the pentadactyl limb of vertebrates example
Pentadactyl limb of vertebrates have 5 digits and is found in 5 classes of vertebrates. Structure of the limb is the same in all classes but have become adapted for different functions.
44
What do the similarities of a pentadactyl limb suggest
A common ancestor
45
What are pentadactyl limbs an example of
Divergent evolution
46
What is divergent evolution
Where a common ancestral structure has evolved to perform different functions.
47
What are analogous structures
Have the same function but different structures because the evolutionary origin is different
48
What are analogous structures an example of
Convergent evolution caused by adaptation to similar environments
49
What does convergent evolution cause
Mistakes when classifying organisms
50
How can mistakes due to convergent morphology be mitigated
By assessing relatedness using biochemical analysis techniques e.g. base sequence or amino acid sequence analysis of a particular protein
51
Homologous structures
Same structure, common evolutionary origin, but different function
52
Analogous structures
Different structure, different evolutionary origin, but the same function
53
How does DNA base sequence work
- Species undergo changes in DNA base sequences during evolution which accumulate until the organisms are so different they're a different species.
- Close related species show more similarity in their DNA base sequence.
54
How does DNA hybridisation work
- Compare DNA base sequence of two species.
- DNA extracted from both, separated and cut into fragments. Fragments mixed and complementary base sequences hybridise together.
55
How does amino acid sequence work
- Sequence of amino acids in protein is determined by the DNA base sequence.
- Degree of similarity in the amino acid sequence of the same protein in two species will reflect how closely related they are.
56
How does immunology work
- Proteins of different species compared by mixing the antigens of one species with specific antibodies of another so that the antigens and antibodies from a precipitate.
- Closer the evolutionary relationship, the more the antigen and antibody react and make more precipitate.
57
Morphological definition of a species
If two organisms look very similar they're likely to be the same species.
58
Reproductive definition of species
Two organisms are the same species if they can interbreed to produce fertile offspring.
59
What definition of species in the most genetically suitable
Reproductive definition but not always easy to apply to field as have to wait time to interbreed.
60
What is taxonomy
The identification and naming of organisms
61
Why is taxonomy important
- Allow us to discover and describe biological diversity.
- Investigate the evolutionary relationships between organisms
- Classify organisms to reflect their evolutionary relationships.
62
Why are binomial systems used
Because they're accepted and understood worldwide. And allows biologists to recognise that species are closely related.
63
What is a binomial system
Each organism is given two names - genus and species. Introduced by Linnaeus and based on Latin
64
What is biodiversity
The measure of the number of species and the number of organisms within each species (species richness and evenness)
65
What happens to the number of species as you move from the equator towards the poles
Number of species decreases.
66
What is succession
The change in composition of a community over time.
67
What is natural selection
Natural selection can generate and change biodiversity
68
What is human influence
Human activity has made the environment less hospitable to living organisms which decreased biodiversity
69
What is extinction
The complete loss of a species
70
What is extinction caused by (natural ways)
A change in climate/habitat, increased competition, predators and diseases
71
How is human activity reducing biodiversity
- Deforestation.
- Pollution.
- Spreading disease.
- Hunting/overfishing
72
What are the three main causes of the decline in numbers of larger mammals
The loss of habitat.
Overhunting.
Competition with invasive species
73
What is conservation
Actively planning to protect a species or habitat e.g. CITES and the SSSI.
74
How does each species represent an important human asset
Plants and animals used to support human civilization as a source of food or pharmaceuticals.
75
What is the assessment of biodiversity using polymorphic loci
An examination of genes and alleles gives an assessment of biodiversity at the genetic level. Focus on the alleles in a population not on individuals
76
What is a locus
A gene's position on a chromosome
77
What does the locus show
Polymorphism if it has two or more alleles at frequencies greater than would occur by mutation alone.
78
What does it mean if a gene has more alleles
Its locus is more polymorphic
79
What does it mean if 98% of the alleles of a particular gene are the same recessive allele
Low biodiversity
80
What does it mean if 50% of alleles in the gene pool were recessive
50% would be the other alleles so the biodiversity is higher.
81
What is an example of polymorphism in humans
The ABO blood grouping system, where the I gene has 3 alleles.
82
What is a genetic profile
A pattern unique to each individual, related to the base sequences of their own DNA.
83
How do individuals acquire different base sequences
Because non coding sequences undergo mutation
84
What is a single nucleotide polymorphism (SNPs)?
Only one base of the non coding sequence differing.
85
What are hyper variable regions (HVR) or short tandem repeats (STRs)
Unique lengths of non coding DNA. Regions of DNA that vary around 20-40 base sequences long
86
What does comparing the number and position of the bands in the DNA profiles of a population indicate?
How similar or different their DNA sequences are
87
The more SNPs and HVRs a population has...
The more differences there are in its DNA profiles so higher biodiversity
88
What are restriction endonucleases
Enzymes which cut the DNA molecule at specific base sequences
89
What is electrophoresis
A process where DNA is separated
90
What is evolution
The process by which new species are formed from pre-existing ones over very long periods of time.
91
What is speciation
When a new species is formed
92
What is adaptive radiation
Several new species evolve from a common ancestor due to natural selection.
93
Natural selection stages
- Mutation - changes in DNA from a new gene.
- Variation - different physical appearance or behaviour.
- Competitive advantage - some organisms are more suited to the environment than others and out-compete them for resources.
- Survival of the fittest - those more suited to the environment are more likely to survive.
Reproduction - those more suited to the environment have more offspring
- Pass advantageous gene to offspring - offspring inherit the advantageous alleles so they are also more suited to the environment.
94
