1
Q
Taxonomy and the taxon groups (8)
A
- The science of classifying living things
- 7 Taxons; Kingdoms Phylum Class Order Family Genus Species
2
Q
Biodiversity (4)
A
- The variation of organisms;
Genetically
Using Habitats
Species variation
3
Q
What criteria is used when classifying in taxonomy (5)
A
- Anatomy and physiology
- Biochemistry
- Behaviour
- Genes
- Phylogeny; evolutionary relationships
4
Q
Classification (2)
A
- Arrangement of organisms into various groups
- Based on their common features/ characteristics
5
Q
Domains
A
- Largest taxa as it only contains three groups
- Eukarya; all the eukaryotes are grouped here- Animals, Plants, Fungi, Protoctist.
- Archaebacteria; closer related to eukaryotes
- Eubacteria
6
Q
Describe the Plant kingdom (4)
A
- Eukaryotic
- Multicellular
- cellulose cell wall
- autotrophic
7
Q
Describe the kingdom of animals (4)
A
- Multicellular
- heterotrophs
- fertilised eggs develop into blastula
- eukaryotes
8
Q
Describe the kingdom of Fungi (6)
A
- Eukaryotic
- Multicellular
- Saprophytic
- contains mycelium
- chitin cell wall
- contains hyphae
- reproduces via spores
9
Q
Why is classification used on organisms? (3)
A
- Clearly identifies species
- Predicts characteristics: if one member in a group has a trait, more likely others will too.
- Finds evolutionary links: characteristics are probably shared due to a common ancestor
10
Q
Adaptations (4)
A
- characteristics that increases an organism’s chance of survival and reproduction in a specific environment
- Anatomical
- Behavioural
- Physiological
11
Q
Examples of Anatomical adaptations (4)
A
- Body Coverings; hair, scales, shells, feathers
- camouflage; blend to the environment which allows hiding from predators
- teeth; shape of them is related to an organism’s diet
- Mimicry; copying appearance and sounds
12
Q
Behavioural adaptations (4)
A
- innate or learned
- survival; eg playing dead
- Courtship; elaborate actions to attract mates
- seasonal; cope with changes in environment (hibernation and migration)
13
Q
Physiological adaptations (3)
A
- Poison; eg venom
- Antibiotic production
- water holding; storage of water such as cactus and camel
14
Q
Adaptations (4)
A
- characteristics that increases an organism’s chance of survival and reproduction in a specific environment
- Anatomical
- Behavioural
- Physiological
15
Q
Examples of Anatomical adaptations (4)
A
- Body Coverings; hair, scales, shells, feathers
- camouflage; blend to the environment which allows hiding from predators
- teeth; shape of them is related to an organism’s diet
- Mimicry; copying appearance and sounds
16
Q
Behavioural adaptations (4)
A
- innate or learned
- survival; eg playing dead
- Courtship; elaborate actions to attract mates
- seasonal; cope with changes in environment (hibernation and migration)
17
Q
Physiological adaptations (3)
A
- Poison; eg venom
- Antibiotic production
- water holding; storage of water such as cactus and camel
18
Q
Evidence for evolution (3)
A
- Palaeontology; fossils
- Comparative anatomy
- Comparative Biochemistry; genetic makeup
19
Q
How is palaeontology useful as evidence for evolution? (4)
A
- Helps predict the age of organisms; older organisms are from deeper layers
- Evidence for simple life forms complex life; Simplier fossils like bacteria are in older rocks whereas complex ones are in newer rocks
- Ecological links; plants occurs before animals therefore animals needed plants to survive
- Anatomical similarities observed; eg skeleton
20
Q
Reasons why the fossil record is incomplete? (3)
A
- Soft body tissue decomposes quickly so organisms that are mainly that will not be persevered
- conditions may have not allowed some fossils to form; eg volcanoes
- some just haven’t been found
21
Q
How is comparative anatomy useful as evidence for evolution? (3)
A
- Differences and similarities with living species can be observed
- Homologous structures are evidence for divergent evolution
- Can show how organisms evolved from a common ancestor due to similar underlying structure; eg vertebrate limbs
22
Q
What are homologous structures?
A
- Structures that are superficially different in organisms but have the same underlying structure
- eg pentadactyl limbs in vertebrates have the same arrangement of bone
23
Q
Types of Variation (2)
A
- Interspecific
- intraspecific
24
Q
Causes of variation (6)
A
- Genetic; inheriting alleles, mutations, sexual reproduction, chance and meiosis
- Environmental reasons
25
Ways of representing genetic variation
- Discontinuous; only certain discrete values- usually genetic
- Continuous; range of values from one extreme to another which usually forms a normal distribution curve
26
Characteristics of a distribution curve (3)
- Mean, median and mode are the same
- bell shape symmetry about the mean
- extreme values are very low whilst most values are close to the mean
27
Types of statistical test (3)
- Standard deviation
- Student's t test
- PMCC
28
Analogous structures
Structures that perform the same roles but have a different genetic origin
Eg fish and whale fin
29
Convergent evolution (2)
- when unrelated species begin to share similar traits
| - This is due to organisms adapting to similar environments or selection pressures
30
Selection pressure
Factors that affect the organism's chances of survival or reproductive success
31
Describe natural selection (4)
- Variation; species show this in their characteristics usually due to genetic causes
- Survival; those better adapted to a selection pressure are more likely to survive and reproduce: eg competition, disease, predation
- Passing alleles; organisms that survive pass on advantageous characteristics to their offspring
- Overtime the gene pool population of the advantageous adaptation increases. Eventually evolution of a new species occur.
32
What is divergent evolution? (2)
- Different species with adaptive features evolve from a common ancestor
- closely related species diversified to adapt to a new habitat
33
How is comparative biochemistry evidence for evolution. (6)
- Differences and similarities in protein molecules
- Links with cytochrome C
- Ribosomal RNA have a slow rate of substitution
- Evolutionary embryology show animals in their earliest phase
- Sequence of DNA bases
- Sequences of amino acids
34
Why are the estimates for the number of species not accurate (4)
- Not all species have been discovered
- Some are difficult to distinguish
- some may have become extinct
- speciation occurs; new species being formed
35
What is the founders effect (3)
- When new colonies are formed geographically isolated from the original one as a result of a dying population
- founders now have different Genes; the one that survived selection pressure
- causes a smaller gene pool
36
Genetic bottleneck (2)
When a large number of organisms in a population dies before reproducing.
This leads to a reduction in genetic biodiversity as the surviving population are usually very genetically similar.
37
Genetic drift
- The frequency of occurrence of an allele vary due to the random nature of alleles being passed on
- This can cause the existence of a certain allele to disappear altogether
38
Horizontal transmission in bacteria
- When bacteria exchange alleles between different species, which can cause greater resistance amongst a wider population
39
Vertical transmission
- Bacteria containing resistant genes and passing them on via reproduction
Biology, Module 4 OCR
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