classification and evolution Flashcards
what is classification
the name given to the process by which living organisms are sorted into groups, the organisms within each group share similar features
what are the taxonomic levels
(domain) kingdom, phylum, class, order, family, genus, species
what does the change in the classification system show us about science
that our scientific knowledge and understanding has developed over time, gathering new information
why do scientists classify organisms
to identify species, to predict characteristics, to find evolutionary links
how do you create a species binomial name
genus (capital letter) and species (lower case letter)
what are the three domains
archaea, bacteria and eukarya
what is a species
a group of organisms that are able to reproduce to make fertile offspring
what are the five kingdoms
prokaryote, protoctista, fungi, plantae, animalia
Animalia
multicellular, has a nucleus, all organelles except chloroplasts, no cell wall, nutrients are acquired by ingestion (heterotrophic feeders), food is stored as glycogen, cilia, flagella, contractile proteins e.g lizards
Plantae
multicellular, nucleus, all contain chlorophyll, cell wall mainly composed of cellulose, nutrients acquired by photosynthesis (autotrophic feeders), make their own food and store it as starch, most don’t move but gametes of some plants move using cilia or flagella, e.g roses
Fungi
unicellular or multicellular, nucleus, no chloroplasts or chlorophyll, cell wall mainly composed of chitin, acquired by absorption mainly from decaying material (saprophytic feeders) some are parasitic, store their food as glycogen, no mechanisms for locomotion, Yeasts
prokaryote
unicellular, no nucleus or other membrane-bound organelles, ring of ‘naked’ DNA, small ribosomes only, cell wall flexible and made of peptidoglycan, no visible feeding mechanism, nutrients absorbed through cell wall or produced internally through photosynthesis, flagellum (some) E.g staphylococcus aureus
Protoctista
mainly unicellular, nucleus, some have chloroplasts and membrane bound organelles, some have cell walls, nutrients acquired by photosynthesis and ingestion of other organisms (autotrophic and heterotrophic feeders), some are sessile, others move by cilia or flagella e.g Amoeba Paramecium
Eukarya
have 80s ribosomes, RNA polymerase contains 12 proteins
Archaea
have 70s ribosomes, RNA polymerase contains between 8 and 10 proteins
Bacteria
have 70s ribosomes, RNA polymerase contains 5 proteins
what are archaebacteria and eubacteria
come from when the prokaryote kingdom divides in two
what is the difference between eubacteria and archaebacteria
eubacteria contain peptidoglycan in their cell walls whereas archaebacteria do not
what is phylogeny
the name given to the evolutionary relationships between organisms
what are the advantages of phylogenetic classification
can be done without reference to Linnaean classification, produces a continuous tree, Linnaean classification can be misleading
how does evolution work
organisms best adapted to their environment are most likely to survive and reproduce, passing on their characteristics to their offspring
what is the evidence for evolution
palaeontology, comparative anatomy, comparative biochemistry (chemical makeup)
where are the oldest fossils found
deeper down in the rock
what evidence is provided by the fossil record
bacteria found in oldest rocks whilst vertebrated are found in more recent rocks, plant fossils appear before animal fossils, links organisms to their common ancestors, allow relationships between extinct and living organisms to be investigated
what are the disadvantages of fossils
soft bodied organisms decompose quickly before they can fossilise, conditions not always right for fossils to form, or fossils destroyed by the Earth’s movements
what is a homologous structure
a structure that appears superficially different ( and may perform different functions) in different organisms, but has the same underlying structure. E.g pentadactyl limb of vertebrates
what is divergent evolution
how, from a common ancestor, different species have evolved, each with a different set of adaptive features, occurs when closely related species diversify to adapt to new habitats as a result of migration or loss of habitat
what is comparative biochemistry
the study of similarities and differences in the proteins and other molecules that control life processes
how do scientists decide how closely two species are related
the molecular sequence of a particular molecule is compared, order of DNA bases or order of amino acids in a protein.
why is ribosomal DNA used to compare species
slow rate of substitution
what is intraspecific variation
variation between members of the same species
what is interspecific variation
variation between organisms or different species
what are the two causes of variation
genetics and environment
what are the causes of genetic variation
Alleles, Mutations, Meiosis, Sexual reproduction, chance
what is an example of a characteristic that is determined purely by genetic variation
your blood group
why are plants affected by environmental factors more than animals
lack of mobility
what is an example of a variation that is purely determined by your environment
scars
what is discontinuous variation
a characteristic that can only result in certain values, no in between values, e.g blood groups, mostly genetic
what is continuous variation
a characteristic that can take any value within a range e.g height and mass of a plant. Environmental factors can have an influence.
what is standard deviation a measure of
how spread out the data is
what is a student’s t test used to measure
compare the means of data values of two populations
what is Spearman’s rank correlation coefficient used to measure
to consider the relationship between two data sets
what are the three types of adaptations
behavioural, anatomical, physiological
what are some examples of anatomical adaptations
body covering, camouflage, teeth, mimicry
what are the adaptations of marram grass
curled leaves to minimise surface area of moist tissue exposed to air, and protect leaves from wind
hairs on the inside surface of the leaves to trap moist air to the leaf
stomata sunk into pits, which make them less likely to open and lose water
A thick waxy cuticle on the leaves and stems reducing evaporation
what are some examples of behavioural adaptations
survival behaviours
courtship
seasonal behaviours e.g migration and hibernation
what are the categories of behavioural adaptions
innate and learned behaviour
what are some examples of physiological adaptations
poison production, antibiotic production, water holding
what are analogous adaptations
structures that have adapted to perform the same function but have a different genetic origin
what is convergent evolution
when unrelated species start to show the same traits
why does convergent evolution occur
because species adapt to fill similar niches
what are some examples of convergent evolution
marsupial and placental mice, flying phalangers and flying squirrels, marsupial and placental moles, aloe and agave
what are selection pressures
factors that affect the organism’s chances of survival or reproductive success
what are the steps of natural selection
genetic variation occurs within a species which is caused by differences in genes and mutations, organisms who are best selected to selection pressures have an increased chance of survival and reproduction (survival of the fittest), the successful organisms pass on the advantageous characteristic onto their offspring , process is repeated for every generation and over time leads to the evolution of a new species
what are some modern examples of evolution
MRSA, Peppered moths, sheep blowflies, flavobacterium
what is the founder effect
when few individuals of a species colonise a new area, their offspring initially experience a loss in genetic variation, often resulting in individuals that are physically and genetically different from their source population.
what is specification
the evolution of a new species
