4.2.2 Classification and Evolution Flashcards
What is the modern system of classification?
- Doman
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is a domain?
- Highest taxonomic rank
- 3 domains = Archaea, Eubacteria, Eukaryote
What is a kingdom?
5 kingdoms = Plantae, Animalia, Fungi, Protoctista, Prokaryote
What is a phylum?
- Groups organisms according to body plan
E.g. Chordata
What is a class?
- Groups organisms to do with general traits
E.g. Mammalia
What is an order?
- Groups organisms according to organisms nature
E.g. Carnivora
What is a family?
- Groups of similar genera, based on reproductive characteristics
What is a genus?
Groups of similar species
What is a species?
A group of organisms that can interbreed to produce fertile offpsring
What is the binomial naming system?
- Genus then species
- Given two Latin names
- Universal across all countries and languages
What are the features of the Animalia kingdom?
- Eukaryotic
- No cell wall
- Multicellular
- A nucleus and other membrane bound organelles
- Heterotrophic (large organic molecules digested into smaller ones for absorption)
- Food store as glycogen
E.g. birds, mammals, jellyfish
What are the features of the Plantae kingdom?
- Eukaryotic
- Multicellular
- Cellulose cell wall
- Autotrophic (use light to produce food by photosynthesis)
- Store food as starch
E.g. algae, ferns, conifers
What are the features of the Fungi kingdom?
- Eukaryotic
- Chitin cell wall
- Usually multicellular or have mycelium (but can be unicellular)
- No chloroplasts
- Saprophytic feeders
- Store food as glycogen
E.g. yeast, moulds
What are the features of the Prokaryotae kingdom?
- Prokaryotic
- Unicellular
- Cells have no nucleus (circular DNA)
- Absorb nutrients or produce internally by photosynthesis
E.g. bacteria
What are the features of the Protoctista kingdom?
- Eukaryotic
- Single cell organisms or a colony of single cells
- Some have chloroplasts
- Move using cilia/flagella/amoeboid mechanisms
- Autotrophs, heterotrophs or both
E.g. amoeba, plasmodium, protozoa
What is artificial classification?
- Based on observed characteristics
- Organisms adapt to their environment so often look similar if they live in a similar environment (convergent evolution)
What is natural classification?
- Includes natural relationships, internal and external factors
- Based on evolutionary relationships
- Evidence used from DNA and amino acid sequences
How are DNA sequences used for natural classification?
- Changes in DNA are caused by mutations
- More differences = less closely related species as have evolved separately for longer periods of time
- Similar DNA sequences = closely related
What is DNA hybridisation?
- DNA from 2 species is extracted, purified and cut into small pieces
- DNA is heated to about 90°C to break the H bonds between the 2 strands
- On cooling, the strands combine with others that have a complementary base sequence
- To separate the strands again, they are heated
- The more similar, the more H bonds form so will take a higher temperature to separate
How are amino acid sequences used for natural classification?
E.g. cytochrome C (protein used for respiration)
- Not identical in all species
- Compare the sequences of amino acids in the Cytochrome C protein to find how closely related organism are
- Similar sequence = closely related
- More differences = less closely related species
How does immunological comparison work?
- Serum albumin from Sp. A injected into Sp. B
- Sp. B produces antibodies specific to the antigen sites on Sp. A albumin
- Serum is extracted from Sp. B; containing antibodies specific to antigens on Sp. A’s albumin
- Serum from Sp. B is mixed with blood from Sp. C
- Antibodies respond to the antigens on the albumin of Sp. C -> response is the formation of a precipitate
- More similar antigens = more precipitate formed and more closely related the species
Why was domain introduced as a new taxonomic rank?
- Extremophiles were discovered
- Classified as Archaea
What are the features of the Bacteria domain?
- Prokaryotic
- Circular DNA
- No membrane bound organelles
- 70s ribosomes
- No introns
- 5 proteins in RNA polymerase
- Can’t grow in extreme temperatures (100°C)
- Peptidoglycan cell wall
- No cytoskeleton
- Not poisoned by diptheria toxin
- Sensitive to streptomycin (antibiotic)
What are the features of the Archaea domain?
- Prokaryotic
- Circular DNA
- No membrane bound organelles
- 70s ribosomes
- Some introns
- 8-10 proteins in RNA polymerase
- Extremophiles can grow in extreme temperatures (100°C)
- No peptidoglycan cell wall
- No cytoskeleton
- Can be poisoned by diptheria toxin
- Not sensitive to streptomycin
What are the features of the Eukarya domain>
- Eukaryotic
- Linear DNA
- Membrane bounded organelles
- 80s ribosomes
- Introns
- 12 proteins in RNA polymerase
- Can’t grow in extreme temperatures (100°C)
- No peptidoglycan cell wall
- Cytoskeleton
- Can be poisoned by diptheria toxin
- Not sensitive to streptomycin
What is phylogeny?
- Evolutionary relationships between organisms
- Looks at how closely related organelles are, which is reflected in classification
What does monophyletic mean?
Belonging to the same phylogenetic group
E.g. humans and gorillas
How was James Hutton evidence for the development of the theory of evolution?
- Uniformitarianism
- Natural processes shape the land and have always done so (e.g. sedimentation, wind erosion and deposition)
- Challenges the view that biblical events caused these changes
How was Charles Lyell evidence for the development of the theory of evolution?
- Fossils are evidence that animals lived millions of years ago
- Agreed with James Hutton
- Included uniformitarianism in his book (Principles of Geology)
How was Charles Darwin evidence for the development of the theory of evolution?
- Found that different shapes of tortoise shells corresponded to different habitats
- Individuals in species show a wide range of variation
- Differences in genes
- Characteristics most suited to the environment are most likely to survive and reproduce
- Successful alleles are passed to their offspring which increases the frequency of successful alleles
How was Alfred Russel Wallace evidence for the development of the theory of evolution?
- Travelled to the Amazon in 1848 and looked at the nature of different species
- Trip to Malaysia 1854 to 1862 to study the differences between animals
- Arrived at the theory of evolution independently
- Asked Darwin to peer review in 1858 and presented the theory of evolution on 1 July 1858
What is the controversy with the theory of evolution?
- God created man in the image
- Suggesting that we evolved from apes in insulting
How is paleontology evidence for the theory of evolution?
- Study of fossils, which are preserved dead animals and plants
- Simple organisms such as bacteria and algae are found in the oldest rocks
- More complex organisms are found in more recent rocks at the top
- Can investigate extinct species too
What is comparative anatomy?
Study of similarities and differences between organisms
What is homologous structure?
Same underlying structure, even though it may appear different and have a different function
What is divergent evolution?
- Homologous structure provides evidence that species evolved from a common ancestor
- Each species with a different set of adaptive features
What is comparative biochemistry?
- Study of similarities and differences between the chemical make up of organisms
- Order of DNA bases, amino acid sequences and proteins
What is comparative embryology?
- Very similar features in early developmental stages
What is interspecific variation?
Different between different species
What is intraspecific variation?
Differences between individuals of the same species
What is continuous variation?
- Tends to be quantitative (any features that can be measured)
- No distinct categories and no limit on the value
- Represented by a line graph
- Controlled by 2+ genes and the environment
- Leads to a range of phenotypes between two extremes
What is discontinuous variation?
- Tends to be qualitative (any feature that can’t be measured)
- Distinct categories with no inbetweens
- Represented by a bar graph
- Controlled by genes
- Leads to limited number of phenotypes with no intermediates
What are anatomical adaptations?
- Body covering (feathers, hairs, scales, spines, shells)
- Colour (camouflage)
- Teeth (adapted for the organism’s diet)
- Mimicry (copying another animal’s appearance to warn off predators)
E.g. thick blubber on whales, streamlined otters
What are physiological adaptations?
- Biochemistry/metabolic processes that take place within an organism
- Hibernation
- Antibody production
- Venom production
- Cacti storage of water
What are behavioural adaptations?
- Survival (e.g. possums playing dead)
- Courtship (e.g. scorpions dancing)
- Seasonal (e.g. migration, hibernation)
- either innate (inherited through genes) or learned (from observing other animals)
What is convergent evolution?
- Different parts of the world provide similar environments and selection pressures
What are the characteristics of marsupial mammals?
- Have a short pregnancy/gestation period)
- Don’t develop a full placenta
- Born early in development, climb into mother’s pouch, attach to teat and continue to suckle
What are the characteristics of placental mammals?
- Longer gestation period
- Develop placenta, allowing exchange of nutrients/waste
- Born more fully developed than marsupial mammals
What are the characteristics of monotremes?
- Lay eggs
- Secrete milk
- Have fur
What is a gene pool?
Total number of alleles in a particular population at a specific time
What is an allele?
Form of a gene
What is a phenotype?
Characteristics of an organism
What is a genotype?
Genetic composition of an organism (the alleles it possesses)
What is reproductive success and allele frequency in natural selection?
- Most populations have a relatively stable size
- All organisms can produce more offspring than can be supported by the supply of food, light and space
- There is competition between members of the same species
- Within any population, there is a gene pool with a wide variety of alleles
- Some individuals have combinations of alleles that make them better at surviving
- Therefore, they reproduce and pass alleles on
What is directional selection?
Individuals favoured in one direction
What is stabilising selection?
Average individuals favoured
How has antibiotic resistance occured?
- Random mutations
- mean some bacteria are resistant
- Creates variation
- Application of antibiotics is the selection pressure
- Resistant bacteria survive, reproduce and pass allele on (greater reproductive success)
How has pesticide resistance occurred?
- Random mutation means some insects are resistant
- Creates variation
- Application of pesticides is the selection pressure
- Resistant insects survive and reproduce
