Define classification
The process of naming and organising organisms into groups based on their characteristics
Name the 8 groups in the classification hierarchy, from largest to smallest
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
Define species
a group of organisms that can interbreed to form fertile offspring
Give a limitation of the reproductive species model
Doesn’t account for species that reproduce asexually
Why can it be difficult to assign organisms to one species?
- species often change both morphologically and genetically overtime
- how ‘similar’ do two organisms need to be to be classed as the same species
- hybrids- classed as new species or not
How can we analyse evolutionary relationships genetically?
- DNA sequences
- Gel electrophoresis
- Bioinformatics
How does gel electrophoresis work?
- agar gel in a tray with wells where the DNA fragments go
- apply an electrical current
- the fluorescent DNA fragments are slightly negatively charged
- move towards the anode and the smaller fragments travel further
- creates a DNA profile with bands of amino acids
How does DNA sequencing work?
- DNA broken into small fragments
- terminated at different lengths using fluorescently marked nucleotides, then duplicated using PCR
- fragments undergo gel electrophoresis, with the smallest fragments travelling further
- can read the base sequence of the fragment according to distance travelled
What is bioinformatics?
the use of technology and software to analyse large amount of biological data. can compare entire genomes and look for where mutations have caused divergence in the phylogenetic tree
How does the scientific community evaluate data?
- papers sent out to expert for peer review to check for validity
- if data and conclusion seem reasonable, results are published in scientific journals
- may also be presented at conferences
Why has the 5 kingdom model of classification come under scrutiny?
- relies heavily on physical observations
- since the introduction of DNA sequencing, new models have been developed
Why is the 3 domain model of classification more accepted by the scientific community?
takes into account research of a particular ribosomal unit and more accurately represents evolutionary relationships than 5 kingdom
What is taxonomy?
the science of describing, classifying and naming living organisms
Define evolution
the process by which natural selection acts on variation to bring about adaptations and eventually speciation
Define biodiversity
biodiversity is a measure of the variety of living organisms and their genetic differences
What are domains?
the 3 largest classification groups, including Eukaryota, Bacteria and Archaea
What kingdom does Archaea contain?
one kingdom: archaebacteria
What kingdom does the bacteria domain contain?
Eubacteria
What are the 4 eukaryotic kingdoms?
protoctista, fungi, plantae, animalia
Describe archaebacteria
ancient bacteria, thought to be found only in extreme conditions but now found in more places e.g. soil
Describe eubacteria
‘true bacteria’ for example bacteria that causes disease and are useful in our digestive system
Describe the 4 eukaryotic families (protoctista, fungi, plantae, animalia)
protoctista- microscopic, some are heterotrophs (have to eat other organisms) and some autotrophs (make their own food by photosynthesis) e.g. amoeda, chlamydomonas
fungi- all heterotrophs, most are saprophytic and some parasitic, they have chitin, not cellulose in their cell walls
plantae- basically all autotrophs
animalia- all heterotrophs that move their whole bodies around during at least one stage of their lifecycles. including invertebrates and vertebrates
What is morphology?
the study of form and structure of organisms
What are analogous features?
features that look similar or have a similar function but are not from the same biological origin
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Topic 1.1 Chemistry for life13
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Topic 1.2 Biological molecules17
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Topic 1.3 Biological molecules 237
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Topic 1.4 Enzymes28
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Topic 2.1 Eukaryotic cells56
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Topic 2.2 Prokaryotic Cells64
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Topic 2.3- Eukaryotic cell division22
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Topic 2.4- Meiosis and sexual reproduction52
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Topic 3.1 Classification44
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Topic 3.2 Natural Selection21
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Topic 3.3 Biodiversity21
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Topic 4.1 Cell transport mechanisms33
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Topic 4.2 Gas exchange22
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Topic 4.3 Circulation72
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Topic 4.4 Transport in plants23
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Topic 5.1 Cellular respiration29
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Topic 5.2 Photosynthesis32
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Topic 6.1- Bacteria and disease42
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Topic 6.2 Non-bacterial pathogens40
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Topic 6.3 The response to infection59
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Topic 7.1- Gene sequencing27
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Topic 7.2 Factors affecting gene expression40
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Topic 7.3 Gene technology15
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Topic 8.1 Genetic information16
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Topic 8.2 Gene pools2
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Topic 9.1 Chemical control in mammals and plants48
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Topic 9.2 The mammalian nervous system5
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Topic 9.3 Homeostasis1
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Topic 10.1 The nature of ecosystems32
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Topic 10.2 The efficiency of ecosystems9
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Topic 10.3 Changes in ecosystems0
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Topic 10.4 Human effects of ecosystems6
