classification and evolution

what is classification?

• arranging organisms into groups based on similarities and differences

what is the point for classification?

• easier for scientists to study

what is taxonomy?

• study of classification

what is the order for classification?

• domain

• kingdom

• phylum

• class

• order

• family

• genus

• species

what is domain?

• highest taxonomic rank

• 3 domains are Archaea, Eubacteria, Eukaryote

what is kingdom?

• traditionally 5 kingdoms which are plantae, animalia, fungi, protoctista, prokaryotae

what is phylum?

• groups organisms to do with body plan (backbone or net etc)

what is class?

• groups organisms to do with general traits (umber of legs etc)

what is order?

• groups according to organismś nature (carnivore/herbivore)

what is family?

• groups of similar genera, based on reproductive characterisitcs

what is genus?

• groups of similar species

what is species?

• group of organisms that can interbreed to give fertile offspring

what is the mnemonic to remember the classifcation?

• Did King Peter Come Over For Green Soup?

what is the binomial system?

• organisms are given 2 latin names

• universal across countries and languages

• same organisms may have different local names

what the features of animalia?

• eukaryotic

• no cell wall

• a nucleus and other membrane bound organelles

• heterophic (large organic molecules digested into smaller ones for absorption)

• food stored as glycogen

what are examples of animalia?

• jellyfish, worms, sponges, fish, reptiles, birds, mammals

what are features of plantae?

• eukaryotic

• multicellular

• cellulose cell wall

• use light to produce food by photosynthesis (autotrophic)

• store food as starch

what are examples of plantae?

• algae, ferns, mosses, conifers, flowering plants

what are features of fungi?

• eukaryotic

• chitin cell walls

• usually multicellular (can be unicellular, yeast) or have mycelium

• no chloroplasts

• saprophytic feeders

• store food as glycogen

what are examples of fungi?

• moulds, mushrooms, yeast

what are features of prokaryotae?

• prokaryotic

• unicellular

• cells have no nucleus (circular DNA)

• absorb nutrients or produce internally by photosynthesis

what are examples of prokaryotae?

• bacteria e.g. E.Coli, Staphylococcus Aureus, blue-green algae

what are features of protocista?

• eukaryotic

• single cell organisms or a colony of single cells

• some have chloroplasts

• move using cilia/ flagellum, amoeboid mechanisms

• nutrients acquired by photosynthesis (autotrophic) or ingesting other organisms (heterotrophic)

what is artificial classifcation?

• based on observed characteristics

• organisms adapt to their environment so often look similar if they live in a similar habitat

what is the problem with artificial classification?

• convergent evolution

what is natural classification?

• includes natural relationships, internal and external features

• based on evolutionary relationships

• evidence used from DNA sequences and amino acid sequences

• mutations in DNA, alter proteins and therefore characteristics

how do we use DNA sequences?

• changes in DNA are caused by mutations

• the more differences between the DNA of different species the less closely related they are

• when one species evolves from another, the DNA will be very similar

what is DNA hybridisation used for?

• used to determine how similar DNA from 2 species is

how is DNA hybridisation carried out?

• DNA is extracted, purified and cut into small pieces

• DNA is heated to about 90 degrees to break H bonds

• when cooled, the strands combine with others that have complementary base sequence

• the more similar the more H bonds

what is the use of hybridisation?

• used recently to aid in classification of flowering plants, no longer use number of leaves

what is immunological comparisons of proteins?

• antibodies of one species will respond to specific antigen on proteins in the blood serum of another (eg. Albumin)

what is the Immunological comparison method?

1. Inject serum albumin from Bradley into a rabbit

2. The rabbit produces antibodies specific to Bradleyś antigens

3. take serum from the rabbit (now contains antibodies for Bradleyś antigens)

4. mix with serum from a spider monkey and baboon

5. the response is formation of a precipitate

6. the greater the precipitate the more antigens in common and the more closely related the species

why have we got 3 domains?

• hydrothermal vents discovered in 1977, prokaryotes found in the extreme conditions ‘extremophiles’ which had features in common with bacteria and eukaryotes

• difference in rRNA, cell membrane structure, flagella structure

what did Carl Woese do?

• introduced domain as a new taxonomic rank

• molecular biology now given greater weight that other features

• extremophiles now classified in a new domain, archaea

• since then other archaea have been discovered, which are not all extremophiles

what are the 3 domains?

• bacteria

• archaea

• eukarya

fill in gaps

what is phylogeny?

• evolutionary relationships between organisms

• it looks at how closely organisms are related

what is phylogenetic?

• study of evolutionary relationships

what is monophyletic?

• belong to the same phylogenetic group

what are features of phylogenetic trees?

• time flows from bottom of tree to top

• branch points are called nodes, nodes show a common ancestor of descendants

• 2 defendants from same node are called sister groups

what is interspecific variation?

• the differences between different species

what is intraspecific variation?

• the differences between individuals of same species

• phenotypic differences can be quite difficult to see sometimes, or can be easier to see

what is continuous variation?

• qualitative-any feature that can be measured

• there is a range of measurements between 2 extremes controlled by (multiple) genes and environment

• e.g. height, length of leaves, length of stalk

what is discontinuous variation?

• qualitative- includes any feature that can’t be measured numerically

• No ‘in between values’, controlled by genes alone

• e.g. blood group, eye colour, shape of bacteria

• represented by bar graphs/piecharts

what does the symbols of unpaired t-test stand for?

what is difference between paired or unpaired T tests?

• if you have 2 different data, from same sample you do paired T-test as there is a relationship between 2 groups

• If you have 2 different samples, you do an unpaired T-test

what does a T-test do?

• will tell you if there is a statically significant difference between tow means when:

• the sample size is less than 25

• the data is normally distributed

give an example of how you would write a null hypothesis?

• there is no statistically significant difference between the germination success of seeds in two soils of different pH

when can you reject the null hypothesis?

• if the value for t exceeds the critical value (P=0.05 or a 5% confidence level), you can reject the null hypothesis (therefore there IS a significant difference)

what did James Hutton say about uniformitarianism?

• natural process shape the land and have always done so (sedimentation, wind erosion and deposition) I challenge the view that biblical events caused these changes

what did Charles Lyell say after Hutton?

• fossils are evidence that animals lived millions of years ago, I agree about uniformitarianism I’ll include it in my new book, principles of geology

what did Darwin say after Lyell?

• ‘Principles of geology’ was a great book gave me some ideas. Uniformitarianism eh? Evolution must be a slow process then…

what was Darwin’s theory of Evolution?

• individuals in a species show a wide range of variation

• differences in genes

• characteristics most suited to the environment are more likely to survive and reproduce

• successful genes are passed to offspring

what did Dawin find out aboutt tortoise shells?

• the shape of tortoise shells corresponded to different habitats

what happened which led to a a collaboration between Wallace and Darwin?

• 1818 Wallace travelled to Amazon and looked at nature of different species

• 1854-1862 trophies to Malaysia to study the difference between animals

• 1858 asks Darwin for a peer review

what happened in 1859?

• Theory of evolution by Natural selection in book of the origin go species by Charles Darwin

why was Darwin’s theory of evolution controversial?

• God created Man in the image of himself- suggesting we evolved form apes is an insult

• The Earth was created about 6000 years ago not millions like Darwin suggested

what is palaeontology?

• study of fossils

what is comparative anatomy?

• study of similarities and differences of organisms

what is comparative biochemistry?

• study of similarities and differences between the chemical make up of organisms

what is homologous structure? (part of comparative anatomy)

• same underlying structure even though may appear different and have different function

what is divergent evolution?

• homologous structure provides evidence that species evolved form a common ancestor, each species with a different set of adaptive features

how would you compare biochemical make up of organisms?

• comparing oder of DNA bases, amino acid sequences, proteins e.g. cytochrome and ribosomal RNA

what is comparative embryology?›

what is and adaptation?

• modified structure, function or behaviour that helps and organism to survive

what are 3 types of adaptations?

• anatomical- physical features (internal and external)

• physiological - processes that take place inside the organism

• behavioural- the way an organism acts

what are types of anatomical adaptations?

• body covering e.g feathers, hair, scales, spines, shells

• colour e.g camouflage

• teeth e.g adapted for the diet the organism has

• mimicry e.g copying another animal’s appearance to warn of predators

What are anatomical adaptations of marram grass?

• sunken stomata

• rolled leaves

• thick cuticle

• hairs on inside of leaf

what are examples of physiological adaptations?

• antibiotic production

• venom production

• hibernation

what are behavioural adaptations?

• survival e.g Possums playing dead

• courtship e.g scorpions dancing

• seasonal e.g migration,hibernation

how can animals get behavioral adaptations?

• innate so inherited through genes

• learned so by observing other animals

• can be combination of both

what does anatomical adaptations provide evidence for?

• convergent evolution because different parts of the world can provide the same niches. the animals the fill those niches can be closely related or sometimes they aren’t related at all but have evolved similar features because of needing to survive in similar habitats

what are features of marsupials?

• have s short pregnancy

• don’t develop a full placenta

• born early in development and climb into mothers pouch, attach to a teat and continue to develop

what are features of placental mammals?

• longer gestation period

• develop placenta which allows the exchange of nutrients and waste products

• born more fully developed

what are features of monotremes?

• lay eggs

• secrete milk

• fur

what does gene pool mean?

• total number of alleles in a particular population at a specific time

what is an allele?

• the form of a gene

what is a phenotype?

• the characteristics of an organism

what is a genotype?

• the genetic composition of an organism, the alleles it possesses

what is Darwin’s theory of evolution?

how does natural selection work?

• all organisms are exposed to selective pressures these will affect an individuals chances of survival, the better adapted the more likely to survive

• for peppered moth, selection pressure was it’s visibility on the tree, the less visible the moth the better able to survive

• organism that are better adapted a re more likely to survive, the will reproduce and pass on the genes including those for the advantageous phenotype, the characteristic will increase in the population

what are 4 steps that could lead to evolution?

1. variation in population caused by differences in genes e.g. mutations

2. survival advantage because those organisms are better adapted a selection pressure, they are more likely to survive (survival of the fittest)

3. alleles are passed on, as successful organism will breed and pass on their alleles for the advantageous characteristics

4. process is repeated generation after generation so frequency of the allele increases through the population

How does antibiotic resistance take place?

• bacteria reproduce quickly during replication mutations can occur in the DNA

• some mutations may lead to bacteria becoming resistant to an antibiotic so variation in population

• when antibiotic used, most bacteria die, those resistant survive and they reproduce passing on the alley for resistance

• proportion of these bacteria increases

how does pesticide resistance take place?

• e.g sheep blowfly

• organophosphates used to kill/ prevent these laying eggs on sheet

• within 6yrs the flies had become resistant to this pesticide

• this happened fast as blowflies had pre-adapted resistance against it, as resistance had occurred randomly before it was needed and hadn’t been lost because it was advantageous

how has flavobacterium evolved?

• evolved to digest nylon 6 found in waste from factories

• scientist believe it was a gene duplication combined with frame shifts mutations which gave this bacteria the enzymes to digest

• good as it can be used to digest some plastic waste