topic 3 : classification Flashcards
list the classification hierarchy
domain, kingdom, phylum, class, order, family, genus, species
what is classification
process of naming and organising organisms into groups based on their characteristics
what is taxonomy
the science of describing, classifying and naming living organisms
why is a classification system needed in biology
The classification system provides great deal of information about the characteristics of organisms.
Using scientific names can therefore act as a shorthand method for describing a plant or animal.
what are the 3 main taxonomic groups (domains)
- archaea
- bacteria
- eukarya
describe archaea
- contain 1 kingdom
- archaebacteria
- they are extremophiles
- separated from bacteria because difference in dna and structure
describe bacteria
- contain 1 kingdom
- eubacteria (unicellular, no membrane-bound organelles
describe eukarya
- contain 4 kingdoms
- protoctista (auto/heterotrophic, single/multicellular, microscoping, some plant-like and some animal like)
- fungi (heterotrophic, cannot photosynthesise, mostly saprophytic (extracellular digestion), chitin cell wall, reproduce by using spores)
*plantae (autrotrophic, carry out photosynthesis using chlorophyll, cellulose cell wall - Animalia (heterotrophic, capable of whole body movement, no cell wall)
what is the binomial nomenclature name ‘template’
Genus species (eg Homo sapiens)
what are the 6 species models
- morphological
- reproductive
- ecological
- mate-recognition
- genetics
- evolutionary
what is the morphological species concept
organisation of species based on their appearance
what is the issue with the morphological species concept
some organisms show sexual dimorphism (great difference in appearance between males and females).
- also, many organisms may look different in different stages of their lifecycle
what is the reproductive species concept
group of organisms with similar characteristics that interbreed to produce fertile offspring
what is the issue with the reproductive species concept
many plant species can interbreed with each other.
- also, it doesnt work for organisms that can reproduce asexuallym or for fossil species
what is the ecological species model
what is the problem with this model
based on ecological niche
many species can occupy more than 1 niche
what is the mate-recognition species model
what is the problem with this model
based on unique fertilisation system or mating behaviour
many species mate with each other
what is the genetic species model
what is the problem with this model
based on DNA evidence
the amt o genetic diff for species to be classified as differents needs to be calculated/decided
what is the evolutionary species model
what is the problem with this model
based on shared evolutionary relationships
not a clear evolutionary pathway for every organism
what is the definition of species
A group of organisms with similar morphological and physiological features that able to breed together and produce fertile offspring.
why does no definition work for species
here are limitations to this model: cross breeding can occur (rare but still possible), some individuals of a species don’t interbreed because they’re geographically separated from each other, and there are other ways to categorise species like through genetic analysis, evolutionary analysis, mate recognition.
- some organisms reproduce asexually
Why can it be difficult to assign organisms to one species?
it is difficult to assign an individual to a species/ identify new ones because over time organisms are always evolving - you would have to say that species are changing morphologically and genetically over time. And then it can be subjective and hard to determine how similar 2 individuals have to be to class them as the same species
what is molecular phylogeny
analysis of the genetic material of organisms to establish their evolutionary relationships
why is phylogeny better than other species models
- shows the evolutionary relationship between organisms
- shows evolution timeline (the further up the tree you go, the more recent the species)
what are some ways to carry out molecular phylogeny (3 ways)
- dna sequencing : finding the base pairs all or part of the genome of an organism
- leads to DNA profiling (patterns are identified by looking at the non-coding areas of DNA) : can identidy relationships between organisms or species as patterns of the DNA are similar
- Bioinformatics : development of software and tools to organise/analyse biological data
- DNA barcodes : produce global standard for species identification by using a short section of DNA and comparing to other organisms (like DNA profiling, the more similar the DNA, the more like the species)
why is gel electrophorisis used
identifying species/evolutionary links through patterns of DNA/RNA and proteins
describe the process of gel electrophorisis
- samples added to wells on agarose gel plate along with known samples to compare
- samples treated with restriction enzymes that cut DNA into fragments
- gel contains dye - binds to the fragments and fluoresces under UV light
- electric current passed through gel, fragments of DNA move at diff rate (shorter ones are faster) from -ve cathode to +ve anode (DNA is negatively charged, so they will move to the positive side)
- switched off when the dye reaches the end of the plate (it moves faster than DNA)
- UV light shone to show patterns
then you can compare the two samples together or compare it to your original set of dna
what is the role of scientific journals, the peer review process and scientific conferences in validating new evidence supporting the accepted theory of evolution
- scientific journals : dedicated to research that other scientists can read
- peer review ; reliability assessed by other scientists in the field (are the data and scientific methods reliable? is the paper significant? can the results be reproduces? is the paper original?)
- scientific conferences : scientists in the same field can discuss ideas and theories. Validity can be challenged, promoting new techniques
what is the evidence for three-domain model
- scientists had accepted that life was categorised into prokaryotic and eukaryotic
- but in 1970, woese collected evidence (RNA sequences) for a new group, Archaea (evidence presented in scientific journal)
- scientists then studied the methods and results in peer review
- repetition and extensions of woese’s work resulted in recognition of Archaea (known that 3 groups have unique RNA seq)
what is the definition of natural selection
process by which best adapted organisms in an environment are most likely to survive and reproduce, passing on advantageous alleles to offspring
what is evolution
process by which natural selection acts on variation to bring about adaptations and eventually speciation
or
process by which allele frequency in a gene pool changes over time
what is the theory of evolution by natural selection
- due to mutations, a variety of alleles are in population, causing genetic and phenotypic diversity
- an environmental change occurs and the selection pressure changes
- individuals have advantageous alleles that give selective advantage - they survive and reproduce, passing on favourable alleles
- over many generations, the frequency of alleles in a pop changes
what is a niche
the role an organism plays in the habitat it lives in
what happens if there are species with the same niche
they compete with each other and the best adapted species will survive
what are anatomical adaptations
involve the form and structure of organism
(eg thich blubber in seals, sharp claws)
what is a physiological adaptation
involve the way the body of organism works, the biochemical pathways/ensymes (eg. mammalian diving reflex (bp lowers when entering water))
what is behavioural adaptations
changes to programmed/instinctive behaviour (migration, mating rituals)
what us the evolutionary race between pathogens and medicine
- bacteria reproduce very quickly
- they can show variation/mutation (meaning that they could be resistant to antibiotics)
- when antibiotics used, it applies a selection pressure against the bacteria without the advantageous gene (they will die out)
- bacteria with resistance survive and reproduce to increase numbers (passing on the favourable alleles)
- over many generations, the frequency of the favourable allele rises
factors that increase antibiotic resistance
- overuse of prescription
- not completing antibioitc course
- poor hygiene in hosptials
- use in food products
- overuse for viral infections
how can antibiotic resistance be overcome
- reduce the use of wide-spectrum antibiotics
- reduce use in farm animals
- prescribic specific antibiotics for infections
- DNA seq to target resistant bacteria
- development of new bacteria
- education to patient (complete course)
what is speciation
formation of new species as a result of reproductive isolation (cannot interbreed)
what is genetic drift
fluctuations in allele frequences - can cause a population become a new species from the original population
what is gene pool
the alleles of all the genes in a population
what is allopatric speciation
- result of physical or geographucal isolation (no interbreeding)
what is an endemic species
evolve in geographical isolation and can only be found in one place
what is sympatric speciation
- occurs within a population living in the same area (reproductively isolated due to mechanical behaviour (birds being attracted to different songs) or seasonal (flowering of plants in diff times)…
or….
result of mutation, where mutated individuals reproduce exclusively from the rest
what is the definition biodiversity
measure of variety of life in an area
how can biodiversity be measured
- number of different ecosystems
- number of species
- number of individual within each species
- genetic diversity
what is genetic diversity
genetic differences between individuals in a species - number of alleles in a gene pool
what is species richness
number of species in the area
what is species abundance
number of individuals in a species
what is relative species abundance
relative numbers of species in the area
why do endemic species have low biodiversity
small gene pool (vulnerable to changes), adapted to 1 environment.
what is the allele frequency
frequency at which the allele appears in a population
what are the ethical reasons for maintenance of biodiversity
- denying future generations the natural resources
- nature is a source of pleasure (cultural services)
- unique combinations of DNA are lost
- humans don’t have the right to cause exinction of species that we share the planet with
what are the economic reasons for maintenance of biodiversity
- purification of air and water
- provisions (food, fibres, fuel and water)
- stabalising atmosphere and climate
- soil formation and nutrient recycling for crops to grow
why is conservation needed
needed for sustaibable development : supplying people with what they need (eg. food, energy, housing) with minimal effects on habitats and wildlife
what is insitu conservation
- conservation of ecosystem and natural habitat where there is a maintenance and recovery of viable populations of species in their natural surroundings.
- this is done by national parks, wildlife reserves
- these areas are monitored and protected from unwanted human activity are
what are the adv and disadv of insitu
+ve
- not removing species from natural ecosystem
- ecological integrity - not as disruptive
- helps larger populations
- cheaper than ex situ
-organisms can adapt and evolve naturally
-ve
- require large area
- risk of disease/natural disaster
- doesnt ensure survival of species
- ecotourism can damage reserves
what is ex situ conservatin
conservaiton of living organisms outside of their natural habitat
how can seed banks be conserved
seeds from endangered olants can be stored n=in a dormant state
- stored in cool, dry onditions, seends are periodially tested for viability
- seeds take up less space and produce many so samples take easily
- propagation in plants
how can animals be conserved (ex situ)
- zoos and wildlife parks often have inbreeding as there are few individuals
- to combat this, they don’t allow organisms to breed with the same partner repeatedly
- use IVF
how can seed banks be conserved
seeds from endangered plants can be stored n=in a dormant state
- stored in cool, dry conditions, seeds are periodically tested for viability
- seeds take up less space and produce many so samples take easily
- propagation in plants
what are the adv and disadv of ex situ
+ve
- protected from poachers
- reproductive techniques maximised
- health monitored
- reintroduce organisms to natural habitat again
-ve
- limited genetic diveristy (inbreeding)
- hard to provide suitable environment
- hard to adjust back to life in wild
- expensive
- harm to seeds by pests
