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24 Cards in this Set
- Front
- Back
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What is classification? |
The organisation of living organisms into groups |
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What do members of a single species have in common? |
-Capable of interbreeding to produce living, fertile offspring -Similar to one another in terms of genes (belong to same gene pool) therefore they resemble one another physically and biochemically -Similar patterns of development -Occupy the same ecological niche |
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What are the features of the binomial system of classification? |
- Universal system understood by all biologists - The first name is called the generic name Denotes the genus the organism belongs to - The second name is called the specific name Denotes the species to which organism belongs to |
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What are the rules that apply to the binomial system? |
- Name printed in italics or if they are handwritten its underlined - First letter of generic name is upper case, specific name lower case - If specific name isn't known it's wrote as sp. |
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What is taxonomy? |
The theory and practise of biological classification |
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What are the two main forms of biological classification? |
Artificial classification Natural classification |
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What is artificial classification? |
Divides organisms according to differences that are useful at the time e.g colour, number of legs Described as analogous characteristics where they have the same function but not same evolutionary origins e.g wings of bird and butterfly have same function but have originated in different ways |
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What is natural classification? |
-Based on evolutionary relationships between organisms and their ancestors -Classifies species into groups using shared features derived from their ancestors -Arranges groups into a hierarchy where groups are contained within larger composite groups with no overlap -Based on homologous characteristics that have similar evolutionary origins regardless of functions |
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Name all the taxa in classification in order of size |
Kingdom Plylum Class Order Family Genus Species |
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What is phylogeny? |
The evolutionary relationship between organisms |
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What are the 5 kingdoms? |
Protoctists Prokaryotes Fungi Plants Animals |
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Why would the sequence of nucleotide bases change? |
Due to mutations |
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How do two species have such different DNA? |
1. One species gives rise to another species during evolution DNA of the species will initially be very similar 2. Due to mutations the sequences of nucleotide bases in DNA of new species will change 3. Over time the new species will accumulate more differences in DNA 4. Expect species that are more closely related to show more similarities in DNA 5. Millions of base sequences in every organism so DNA contains a vast amount of information about the evolutionary history |
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How do you determine similarities in DNA? |
DNA hybridisation |
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What happens when DNA is heated? |
The double helix separates into two complementary single strands |
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Describe the method of DNA hybridisation? |
1. DNA from 2 species extracted, purified and cut into short pieces 2. 1 species of DNA labelled by attaching radioactive/fluorescent marker 3. Mixture of both sets of DNA heated 4. Mixture cooled to allow complementary strands to combine 5. Some of double strands that form will be made from both species. This is called hybridisation and new strands called hybrid strands Identified by fact they are 50% labelled |
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Continued method of DNA hybridisation |
6. Hybrid strands separated out and temperature is increased in stages 7. At each temperature stage the degree to which the two strands are still linked is recorded 8. If species are closely related they will share many complementary nucleotide bases Means more hydrogen bonds linking the hybrid strand so higher temperatures would be needed to separate |
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How have flowering plants been classified in the past? |
By physical features Two groups are single seed leaf and two single leaves |
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What is the new classification of method of flowering plants? |
-There are three genes that all plants have -You compare DNA sequences of each species using computer analysis -Phylogenetic tree for the families of the flowering plants devised based on DNA sequence of species |
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What did the plant phylogenetic tree reveal? |
Showed how species have evolved into natural groups Groupings represent evolutionary relationships better than any previous form of classification |
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How can amino acids be used to show evolutionary relationships? |
Sequence of amino acids in proteins determined by DNA Degree of similarities in amino acid sequence of same protein in two species will reflect how closely related two species are |
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How can proteins of different species be compared? |
Using immunological techniques |
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What is a serum? |
Bodily fluids |
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How are proteins compared? |
1. Serum from species A is injected into B 2. B produces antibodies specific to all antigen site in the serum from A 3. Serum extracted from B which contains antibodies specific to antigens from species A 4. Serum from B mixed with serum from species C Response is formation of precipitate 5. Greater the number of similar antigens, the more precipitate is formed, more closely related the species are |
