Classification and Evolution

• Define the terms "classification", "taxonomy", "taxonomic group", "hierarchical", and "phylogenetic"

  Classification - the arrangement of organisms into taxonomic groups based on observed similaritiesTaxonomy - Branch of science concerned with classification, especially of organismsTaxonomic group - The hierarchical groups of classificationHierarchical - An organism can only belong to one group at each taxonomic level. Related groups at one level are grouped into more inclusive groups at the next higher level.Phylogenetic - The evolutionary relationships between organisms
• List the seven taxonomic groups, in order, from the broadest to the smallest.

  Kingdom, Phylum, Class, Order, Family, Genus, Species
• Name the taxonomic level that has been added above kingdom.

  Domain
• 4. Give 3 reasons why scientists classify organisms.

  To identify species, To predict characteristics and to find evolutionary links
• Define the term "species"


  The smallest and most specific taxonomic group. Group of similar individuals capable of exchanging genes or interbreeding to produce fertile offspring.
• Explain why horses and donkeys are separate species, and why mules are not given a scientific name and are not a separate species.

  When horses breed with other horses they produce fertile offspring. When donkeys breed with other donkeys they produce fertile offspring. When donkeys and horses breed they produce a mule (or a hinny) which are infertile - they have an odd number of chromosomes - meiosis and gamete production cannot take place correctly. This means horses and donkeys are separate species and mules are not
• Define the terms "Scientific name" "Binomial nomenclature" "Generic name" and "Specific name"

  Scientific name - Name given to organisms consisting of 2 parts. Unique name given to each species.Binomial nomenclature - The scientific naming of a species with a Latin name made of two parts - the first indicating the genus and the second the speciesGeneric name - First word of the scientific name of an organism indicating its genusSpecific name - Second part of scientific name indicating organisms species
• Explain how scientific names of species are derived from the classification of a species and state the conventions used in writing them

  Genus then species Typed - italics, Handwritten - underlinedLowercase apart from first letter of genus
• Explain the value of the binomial nomenclature system to the scientific community

  Universal whereas common names vary from place to placeNo two species share the same nameProvides information about relationships between species
• Name the 5 kingdoms and give examples of the organisms they contain

  Prokaryotae - bacteriaProtoctista - single celled eukaryotes - amoebaFungi - yeasts, moulds, mushroomsPlantae - plantsAnimalia - animals
• Compare the features of the kingdoms

  Prokaryotae - Prokaryotic cells, No membrane bound organelles, small ribosomes, circular DNA. Cell wall - murein/peptidoglycan. Unicellular. Nutrition - absorbed through wall or produced internally. Some photosynthesise. No chloroplasts. Locomotion - bacteria flagellum. Varied methods of storing carbohydrateProtoctista - Eukaryotic cells. Varied cell wall (some have some don't) Mainly unicellular - if multicellular organisation is very simple tissues. Nutrition - photosynthesis, ingestion of other organisms, some are parasitic. Some photosynthesise and some have chloroplasts. Some are sessile and others have flagella cilia or amoeboid mechanisms for locomotion. Varied methods of storing carbohydrate.Fungi - Eukaryotic. Chitin cell walls. Unicellular or multicellular - if so organisation is hyphae. Nutrition - Absorption from decaying material - sprophytic, some parasitic. No photosynthesis. No locomotion. Store carbohydrates as glycogen.Plantae - Eukaryotic. Cellulose wall. Multicellular with complex tissues. Photosynthesise - autotrophic - have chloroplasts. Most plants no locomotion. Store carbs as starchAnimalia - Eukaryotic. No cell wall. Multicellular with complex tissues. Nutrition by ingestion - heterotrophic. No photosynthesis. Locomotion - cilia, flagella, muscular organs. Store carbs as glycogen.
• Explain why protoctista has been described as a dumping ground for species

  Any eukaryotic organism that does not fit into fungi, plantae or animalia is classified as protoctista. Kingdom is very varied.
• State the 3 domains of life and the 6 kingdoms that this system of classification uses.

  Bacteria, Archaea and Eukarya.Within bacteria there are Eubacteria, within archaea there are Archeabacteria and within Eukarya there are Protoctista, Fungi, Plantae and Animalia.
• Describe the characteristic features of each of the 3 domains: Eukarya, Archaea, and Bacteria.

  Eukarya - Eukaryotic, 80s ribosome, 12 proteins in RNA polymerase, Cellulose or Chitin cell wall if presentArchaea - Prokaryotic, 70s ribosome, 8-10 proteins in RNA ploymerase, cell wall is not peptidoglycanBacteria - Prokaryotic, 70s ribosome, 5 proteins in RNA polymerase, Peptidoglycan cell wall
• Describe the evidence used to create the "Three Domain System" of classification.

  Analysis of rRNASequences of nucleotides in ribosomal RNA - Archaea and Eukarya closely linked, bacteria separateThe cell's membrane lipid structureSensitivity to antibioticsMolecules in cell wall
• Describe how new explanations of phenomena are scrutinised by the scientific community and may end up replacing earlier explanations.

  1 - Write scientific paper describing methods, data, hypotheses and conclusions2 - Submit the paper to a scientific journal3 - paper read by other scientists before accepted for publication4 - Critical evaluation of the paper by the scientific communityAlso can give lectures, attend conferences, publish on internet etc.
• Explain what occurs in the "peer review" process.

  Check conclusions drawn from data are logical and validCheck data is acceptable and reliableCheck for plagiarismOther scientists try to repeat experiments, test theories etc.
• Define the terms "phylogeny" and "phylogenetic tree or evolutionary tree".

  Phylogeny - The evolutionary relationships between organismsTree - branching diagram or "tree" showing the inferred evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.
• Define the terms "sister group", "common ancestor", "node", and "tip" in relation to phylogenetic trees. (F)

  Sister group - closest relatives of a given unit in an evolutionary treeCommon ancestor - most recent ancestral form or species from which two different species evolvedNode - Point at which line branchesTip - end of a branch
• Describe the advantages of using phylogenetic trees as a form of classification as opposed to just using taxonomic groupings.

  Can see more clearly the evolutionary relationships and common ancestors of species
• State 3 different sources of evidence for evolution

  Paleontology - FossilsComparative anatomy and comparative biochemistry (inc. Genomics and proteomics (comparing DNA and proteins))Experiments and observations eg. selective breeding and lab experiments showing evolution
• Explain how the (relative) age of fossils can be determined

  Using the different layers (strata) in rocks and comparing
• Explain how the fossil record provides evidence for evolution.

  Evidence of change over time - how organisms originally were, how they were at different times and how they are now
• Explain how comparative anatomy provides evidence for evolution.

  Shows divergent evolution from homologous structures
• Define the terms "homologous structure" and "divergent evolution".

  Homologous structure: A structure that appears superficially different (and may have different functions) in different organisms but has the same underlying structure.Divergent evolution: A common ancestor species diverges over time into two species, resulting in a new species becoming less like the original one.
• Define the term "comparative biochemistry".

  The study of similarities and differences in the molecules that control life processes. inc. proteins and DNA
• Explain how comparative biochemistry provides evidence for evolution

  The small changes in sequences of nucleotides in DNA or amino acids in proteins
• Define the terms "variation", "interspecific variation", and "intraspecific variation".

  Variation: Differences in characteristics between organismsInterspecific variation: Between members of different speciesIntraspecific variation: Between members of the same species
• Name and describe the two causes of variation.

  Genetic variation - caused by differences in genes inherited from parentsEnvironmental variation - caused by different conditions in the environment
• Describe 5 causes of genetic variation between individuals within a population

  Alleles - different versions of a gene that in different combinations code for different characteristicsMutations - changes to sequence of nucleotides can change proteins produced etcMeiosis - independent assortment and crossing overSexual reproduction - inheriting a combination of alleles from each parent so different to bothChance - Each gamete unique and chance as to which ovum fuses with which sperm etc.
• State 3 characteristics that are solely genetically-determined, 3 that are solely environmentally-determined and 3 that are clearly a combination of genetics and the environment

  Genetics: Blood group, eye colour, tongue rollingEnvironment: Scars, piercings, dyed hair etc.Both: Height, weight, skin colour
• Explain how twin studies can help identify the relative influence of genetics and the environment on characteristics.

  Identical twins have the same genetics so all variation would be due to differences in environment. Non-identical twins are often raised in incredibly similar environments so variation largely due to genetics. (Carefully controlled environments as far as possible)
• Define the terms "continuous variation" and "discontinuous variation".

  Continuous variation: A characteristic which can take any value within a rangeDiscontinuous variation: A characteristic that can only result in certain discrete values
• Describe the causes of variation that result in discontinuous variation

  Tend to be genetic e.g. blood type normally by a single gene
• Define the terms "polygenic", and "multifactorial"

  Polygenic - controlled by multiple different geneesMultifactorial - involving or dependent on many factors
• Describe the causes of variation that result in continuous variation.

  Tends to be environmental or a combination of many environmental and genetic factors
• Define the term "adaptation" and state the 3 types of adaptation


  Characteristics that increase an organism's chance of survival and reproduction in its environment.Anatomical adaptions, Behavioural adaptations, Physiological adaptations.
• Define the terms "anatomical adaptation", "behavioural adaptation", and "physiological adaptation", and give 4 examples of each.

  anatomical - physical features (internal and external)Camouflage, Curled or rolled leaves to minimise water loss, feathers for flight in birds, shell on a snail for protectionBehavioural - the way an organism actsCourtship dances, Freezing when spotted by a predator, hibernation, migration, playing deadPhysiological - metabolic processes or processes conducted by specialised tissues or organsAbility to produce antibodies in response to infection, Haemoglobin adapted to life at high altitude in llamas, Production of poison, Salt tolerance or tolerance of anaerobic conditions in plants
• Define the terms "analogous structure" and "convergent evolution".

  Analogous structure - structures that have adapted to perform the same functions but have different genetic or evolutionary originsConvergent evolution - When distantly related species share similar features that perform the same function but have a very different genetic or evolutionary origin
• Explain why organisms from different taxonomic groups may show similar features.

  Same/similar niche or lifestyle so same/similar conditions/needsEach species has the benefit of having a structure that performs that function so the appropriate genes/alleles are passed on (may be different genes/alleles in each species)