Classification and evolution Flashcards
What is classification
- the process by which living organisms are sorted into groups
What are the taxonomic groups
- kingdom
- phylum
- class
- order
- family
- genus
- species
Why are organisms classified
- identify species
- predict characteristics
- find evolutionary links and common ancestors
Why is a single classification system used worldwide
- allows scientists to share finding and link animals across continents
What is a species
- a group or organisms that are able to reproduce to produce fertile offspring
Why might an organisms by infertile (so not a species)
- odd number of chromosomes
- means meiosis/ gamete production can’t occur
Classification of humans
- d= eukarya
- k= animalia
- p= chorolata
- c= mammalia
- o= primates
- f= horminidae
- g= homo
- s= sapien
What is the name for how species are named
- binomial nomenclature
How are species named
- genus species
- ( in italics)
What are the 5 kingdoms
- prokaryotae
- protoctista
- fungi
- plantae
- animalia
Features of prokaryotae
- unicellular
- no nucleus or other membrane bound organelles
- small ribosomes
- no visible feeding mechanism (nutrients absorbed)
Features of protoctista
- mainly unicellular
- nucleus and other membrane bound organelles
- some have chloroplasts
- some immobile, some move by cilia/flagella
- nutrients acquired through photosynthesis
- e.g. amoeba
Features of fungi
-uni or multicellular
- nucleus and other membrane bound organelles
- chitin cell wall
- no chloroplasts
- no mechanisms for locomotion (movement)
- food stored as glycogen
- nutrients acquired through absorption (often of decaying matter) - saprophytic
- some are parasitic
- e.g. mould, yeast
Features of plantae
- multicellular
- nucleus and other membrane bound organelles
- chloroplasts and chlorophyll
- cellulose cell wall
- store food as starch
- nutrients acquired through photosynthesis (autotrophic)
- most don’t move
- e.g. grass, trees
Features of animalia
- multicellular
- nucleus and other membrane bound organelles
- no chloroplasts
- move with aid of flagella, cilia, contractile proteins
- heterotrophic- acquire nutrients through ingestion
- food stored as glycogen
- e.g. mammals, repitles
How is DNA used to discover evolutionary links, example
- when organisms evolve, DNA changes (determines proteins and characteristics)
- comparing the DNA similarity between species discovers evolutionary relationships
- e.g. haemoglobin = differs in amino acid numbers between different species, similar structure indicates common ancestry
What is a domain, what are they
- further level of classification at the top of the hierarchy
- classifies organisms into 3 domains, and 6 kingdoms
- eukarya, archaea, bacteria
- organisms in each domain contain unique form or rRNA and different ribosomes
Features of Eukarya
- 80s ribosomes
- RNA polymerase contains 12 proteins
Features of archaea
- 70s ribosomes
- RNA polymerase contains 8-10 proteins
Features of the bacteria domain
- 70s ribosomes
- RNA polymerase contains 5 proteins
What are the 6 kingdoms domains cause
- protoctista, plantae, animalia, fungi remain the same, under the EUKARYA domain
- arachaea and bacteria split prokaryotae into eubacteria and archaeabacteria
Features of archaea bacteria, example
- single celled prokaryotes
- known as ancient bacteria
- can live in extreme environments (e.g., acidic or thermal)
- e.g. methanogens
Features of eubacteria
- single celled prokaryotes
- known as true bacteria
- more common than archaea bacteria
- found in all environments
- peptidoglycan cell wall
What is phylogeny
- the evolutionary relationships between organisms
What is phylogenetics
- the study of evolutionary history of groups or organisms
- reveals which groups of organisms are related, how closely related they are
What is a phylogenetic tree
- a diagram used to represent the evolutionary relationship between 2 organisms
Features of phylogenetic trees
- branched diagram
- shows how different species evolve from a common ancestor
- earlies species at base of tree, most recent at tips of branches
- produced by looking at differences and similarities in species genetic makeup and physical characteristics
- the closer the branches, the closer the evolutionary relationship
Advantages of phylogenetic classification
- can be done without reference to Linnaen classification
- classification uses phylogeny to confirm or change classification groups
- produces a continuous tree rather than discrete taxonomic groups- doesn’t force organisms into groups
- advantages over linnaen (suggests different groups with same rank are equal, when may not be comparable)
What is the definition of evolution
- the theory that describes the ways that organisms evolve or change over time due to natural selection
Process of developing the theory of evolution 1= 1831
- Darwin reads principles of geology, which suggests fossils were evidence of animals millions of years ago
- also promoted uniformitarianism- idea Earth is shaped by forces
- caused Darwin to think evolution was a slow process
Developing theory of evolution 2- galapogus
- Darwin did observation in Galapogos islands, studied Finches
- noticed different islands had different finches- different shape claws and beaks
- design of finches beaks linked to foods available (longer beaks suited to more food, survive and reproduce)
- over time whole island population share characteristic
Developing evolution 3- sending, Wallace
- sent specimens of organisms back to UK to preserve and classify organisms
- spot links between organisms Darwin hadn’t
- when he returned, studies pigeons to gain direct evidence his ideas were correct
- at same time, Wallace working on his own theory of evolution, sent his ideas to Darwin in 1858 for peer review
- similar ideas, did joint presentation to Linnaen society in July 1858
Developing evolution 4= book
- 1859=Darwin published on the origin of species
- named theory he and Wallace presented- evolution by natural selection
- controversial at time as contradicted religious beliefs about God creating all organisms
- split community before being accepted
What is paleontology
- the study of fossils and the fossil record
How do fossils form, how are they used
- form when animal and plant remains are preserved in rocks
- sediment deposited on earth to form layers of rock- strata
- different layers respond to different geographical eras
- within rock strata, fossils are different, forms sequence of oldest to youngest, showing organisms have gradually changed over time
Evidence provided by the fossil record
- fossils of simplest organisms found in oldest rocks, complex in more recent
- sequences organisms are found in matches ecological link to each other
- fossils allow relationships between extinct and extant organisms to be studies
- scientists can show how closely related organisms have evolved from the same ancestor (fossil similarity)
What is comparative anatomy
- the study of similarities and differences between organisms anatomy
What are homologous structures
- a structure that appears superficially different in different organisms but has the same under lying structure
- structures may perform different functions
What is divergent evolution
- how different species evolve from the same common ancestor, each with a different set of adaptive functions
When does divergent evolution occur
- when closely related species diversify to adapt to new habitats as a result of migration or loss of habitat
What is comparative biochemistry
- study of similarities and differences between the chemical makeups of organisms, which control biological or physiological processes
- proteins, DNA, amino acid sequence
- allows estimation of when 2 organisms shared a common ancestor
What is variation
- differences in characteristics between organisms
Interspecific vs intraspecific variation
- INTER= between members of DIFFERENT species
- INTRA= between organisms WITHIN a species
What is genetic variation, factors that cause it
- variation due to the genes and alleles an individual possesses
- alleles, mutations, meiosis (crossing over and independent assortment), sexual reproduction, chance
What is environmental variation, what does it affect more, examples
- variation due to environmental experiences
- plants are greater affected as they are immobile
- e.g. scars
What is continuous data, how can it be displayed, examples
- a characteristic that can take any value within a range
- graduation in values from 1 extreme to another
- controlled by a number of genes- polygenetic
- displayed by histogram line graph
- height
What is discontinuous variation
- characteristic that can only result in certain values
- discrete/categorical data
- purely determined by single/few genes
- displayed by bar chart/pie chart
- e.g. blood group
Features of a normal distribution
- mean=median=mode
- bell shaped curve
- symmetrical
- number of individuals at each extreme are low
What is standard deviation, link to variation, % of values within s.d.
- a measure of how spread data is
- characteristic with a high s.d has a large amount of variation
- 68% of values within one s.d from the mean, 95% within 2, 99.7% within 3
What is the students t-test
- compares the means on data values of 2 sets of data/populations
When is data significant for the students t-test
- if the calculated values is less than or equal to p value (0.05)
What is spearman’s rank correlation co-efficient, meanings of correlations
- considers the relationship between 2 sets of data
- positive correlation= as 1 set of data increases in value, o does the other
- negative correlation= as 1 set of data decreases in value the other increase
When is spearman’s rank correlation coefficient significant
- when the calculated value is less than or equal to the critical (0.05)
What does p=0.01 mean
- there is a 1% probability of the difference being due to chance only
- would happen 1/100 times due to chance
What is an adapatation
- a characteristic that increase an organisms chance of survival and reproduction in its environment
What are anatomical adaptations, examples
- anatomical= internal and external physical features
- body covering
- camouflage
- teeth
- mimicry (copying other)
What are behavioural adaptations, examples
- learnt or inherited ways of how an organism acts
- survival behaviours (freeze)
- courtship (attract mate)
- seasonal behaviours- migration, hibernation
What are physiological adaptations, examples
- processes that occur within an organism
- poison production
- antibiotic production
- water holding
- reflexes, blinking, temp regulation
What is convergent evolution, why does it happen
- when unrelated species start to share similar traits
- evolve due to similar environments or selection pressure
What are analogous structures, example
- structures that have adapted to perform the same function but have a different genetic origin
- e.g. whale tail fins and fish tail fins
Examples of convergent evolution- moles
- marsupial and placental moles both burrow through soft soil to find worms
- both have streamlined body, modified forelimbs, velvety fur
- differences= marsupial are white/orange, placental are grey
- 2 subclasses separated millions of years ago, now found in separate continents, but are similar
What are selection pressures, examples
- factors that affect an organisms chances of survival/reproductive success
- e.g. disease, predation, competition
What is natural selection
- organisms best adapted to their environment are more likely to survive and reproduce, these adaptations become more common in the population
Process of natural selection
- organisms within a species show variations in characteristics due to genetic variation
- organisms who’s characteristics are better adapted to selection pressures have an increased chance of survival and reproduction
- successful organisms reproduce and pass on advantageous allele
- process repeats over generations, advantageous alleles become more frequent in the gene pool
- over long periods involving multiple genes, process can lead to evolution of a new species
Examples of evolution- Antibiotic resistant bacteria
- MRSA developed resistance to many antibiotics
- bacteria reproduce rapidly so evolve rapidly
- DNA can be altered when reproduce leading to a mutations which can provide resistance
- resistant bacteria survive and pass on resistance, increasing the population
Examples of evolution- peppered moths
- before industrial revolution, pale moths advantageous, more camouflage on trees
- after industrial revolution, trees darker so dark moths advantaged
- lighter now so paler adapted- constant change in gene pool frequency
Examples of evolution- sheep blowflies
- lay eggs near sheep tail, which hatch and cause sores
- developed resistance to pesticides, adapted reproduce and pass on allele
- some have a pre-adaptation to pesticides- helps rapid development of resistance
Examples of evolution- Flavobacterium
- evolved due to opportunities in environment
- live in waste water from factories containing nylon 6
- bacteria evolved to digest nylon, provides nutrient and cleans water up
