classification and evolution Flashcards
why do we classify (state 4 reasons)
- for convenience
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help us see the relationship, between species.
what are the problems, with using observable features, to classify
- insects and birds, both have wings but are not closely related
- some features of an organism are not observable
outline the other possible approaches to classification
- behaviour
- physiology
- cellular structure
- molecular analysis
define taxonomy
- the study of the principals, behind classification
- involves naming organisms and organising them into groups, based on characteristics and differences.
who was Carl Linnaeus
the first scientist, to formally do taxonomy.
what is a domain
- the highest taxonomic rank
- split into 3
- Archaea, bacteria and eukaryote
what is a kingdom
- 5 traditionally
- plantae, animalia, fungi, Protoctista and prokaryote
what is phylum
a major sub division, of a kingdom, that have the same body plan, e.g. the possession of a back bone
what is class
a group of organisms, that posses the same general traits, i.e. the same number of legs
what is order
a subdivision, of class, which needs additional information i.e. eat eating
what family
a group of closely related species
what is species
basic unit classification
at which taxon level, does the greatest difference exist
domain
at which taxon level do we need the greatest amount of information to classify
species
what is the biological definition of a species
a group of organism’s, that can freely interbreed to produce fertile offspring
what is the definition of phylogeny
the study of how closely related different species, it is the study of the evolutionary relationships, between organisms
what is the phylogenetic definition of a species
- a species, is a set of individuals, which have the same evolutionary, lineage, where two lines diverge, sufficiently they are called separate species.
- (textbook definition - a group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics.
what is cytochrome c
a protein that is used in respiration
name 3 examples, of Protoctista
- chlorella
- amoeba
- plasmodium
given a common feature of organisms in the animal kingdom
A heterotroph is an organism that eats other plants or animals for energy and nutrients.
what is mycelium
a thread like structure, made up of hyphae
what is the circular loop of DNA found in bacteria called
plasmids
why have we been able to improve the way we group species
- new data
- new technology
- peer review
- evaluation of ideas / theories/ reclassification
what is molecular phylogeny
looks at DNA molecules, and proteins, to see how closely related organisms are.
what do phylogenetic trees shows us?
it shows us, the evolutionary relationship, between organisms based on molecular differences as a result of mutations accumulated over time
what is the change in a sequence of bases called
a mutation
how can we use DNA to classify
- by using PCR and Electrophoresis to compare DNA fingerprints
- to see how similar or different two organisms are.
what is Electrophoresis
Gel electrophoresis is a technique used to separate DNA fragments according to their size. DNA samples
what is PCR
Polymerase chain reaction (PCR) is a common molecular biology technique used in most applications of gene technology, for example, DNA profiling (eg. identification of criminals and determining paternity) or genetic engineering. It can be described as the in vitro method of DNA amplification.
who came up with the idea, of the three domain classification system
Woese
what are the key differences, between the Bacteria and Archaea, that suggest that they should be classified as different domains?
- differing enzymes, to cope with extreme environments (extremophiles)
- differing mechanisms, for DNA replication and RNA building
- differing cell membrane
- differing cell wall
- differing flagella
what similarities, between the Eukarya and Archaea domains suggest that they have a more recent common ancestor, compared to Archaea and Bacteria
- more similar enzymes
- similar mechanisms, for DNA replication and RNA building
- similar Proteins, associated with DNA.
what is meant by convergent evolution
where two organisms show similar adaptations, but are classified in different taxonomic groups.
how does convergent evolution by observable features, prove to be more difficult
due to the organism, having very similar adaptions, which may make it difficult, for scientist to make clear classifications, between the two species, just by observable features.
why is it essential, to use molecules, such as DNA and cytochrome C when looking at evidence for classification
allows for very specific comparison, to see if there is differences, in the coding/ build up of the genetic material, that makes up the molecules
what is monophyletic
in the same phylogenetic group (from the same ancestor)
what is evolutionary distance
when looking at an evolutionary tree, a greater evolutionary distance, means that the species diverged longer ago
what is an evolutionary tree
a diagrammatic representation, of evolutionary relationships
what is cladistics
members, of a group, that share unique features, and they must share a common evolutionary history be closely related
what does extant mean
still living
what is variation
the presence, of differences between individuals
how do identical twins form
1 cell divides into 2
are identical twins exactly the same? why?
no, original DNA identical, but cell division post may introduce mutations, environmental factors.
what is variation between species know as
interspecific
what is continuous variation
two extremes, and a full range of intermediate values. ( most individuals, are close the mean (normal distribution)
what is discontinuous variation
two or more distinct categories where there are no intermediate values. (regulated by 1 gene and not influence, by the environment
what is variation caused by
- genetic
- environmental
what are some examples, of continuous variation
- height
- leaf length
- toadstool stalk length
- number of flagella
what sort of graph, would you use to show discontinuous variation
a bar graph
what sort of graph, would you use to show continuous variation
a histogram
explain why discontinuous variation, is often caused by just one gene
presence of different alleles, can produce the difference between characteristics, or decide, whether the characteristic is present or absent
explain, why skin colour is a continuously variable feature
- due to their being a large range of possible skin colours, however some tones of skin colour, will be much more common than others
what are the 3 ways, of calculating an average
- median
- mode
- mean
what is range (maths context)
a measure, of how spread out you data is.
what is standard deviation
standard deviation, is a quantative measure, that looks at the spread of data about the mean
what does a large standard deviation tells us?
that there is lots of variation within a data set
what does a small standard deviation tells us?
that there is little variation within a data set
what is an adaptation
a characteristic, that enhances survival, in a habitat
what is a behavioural adaption
an aspect, of the behaviour of an organism, that increases it’s chance of survival
what is a physiological adaption
- an adaptation, that ensures the correct functioning of cell process
- e.g. hibernation, produce poison
what is anatomical adaptation
- a structure that enhances survival
- e.g. streamlined for water movement
what is convergent evolution
- adaptions, are selected for by the environment
- therefore, two unrelated species living in similar habitats, can evolve similar adaptions.
what is a genotype
the genetic makeup of an organism
what is a phenotype
an individuals observable traits (physical characteristics)
what is a mutation
a change in the DNA sequence of an organism
what is variation
differences between individuals
what is selection pressure
an evolutionary force, that causes a particular phenotype to be more favourable in certain environmental conditions.
what is natural selection
the selection by the environment, of particular individuals, that show certain variations
what were the 4 observations that Darwin made
- overproduction of offspring
- struggle for survival
- offspring, are generally similar to their parents
- variation exists
what is speciation
the formation of a new species, from a pre - existing species, that can no longer inter breed to produce a fertile offspring.
list 3 biotic factors
- food availability
- predator
- diseases
list 2 abiotic factors
- physical factors i.e. temperature
- chemical factors
how has pesticide resistance developed
- pesticides, create a strong selection pressure.
- those, with mutation, for resistance will survive and reproduce.
- the whole population, can very quickly become resistant.
why is pesticide resistance a problem, for the human population
- higher concentration of pesticides, need to be applied
- resistant individuals, do not die and instead are eaten by consumers, pesticides, can then pass through the food chain and accumulate (bioaccumulation)
- new pesticides are costly
- resistance, causes reduction in crop yields and increased disease transmission.
what are fossils
animal and plant remains, preserved in rocks
what do they show
anatomical features and can help to show relationships and age of species
how can fossils be used as evidence for evolution
- modern species, were often more complex
- similarities, between closely related species.
- different bands of rock, help age fossils - oldest further down
- organism, have changed over time.
what are the issues with using fossils
- not complete record
- conditions, need for fossilisation, no always present
- organisms bodies decompose quickly
- many fossils, destroyed or lie undiscovered.
