species Flashcards
why are species important to biologists
knowing biodiversity
monitor change of natural enviornmental changes and changes because of human activity
what do biologists look for in species
adaptations within a species
changes in number of species in specific enviorment
what species concept did linneaus develop
morphological species concept
whats the morphological species concept
only looked at features and apperance of species to classify them
whats difficult about classifying species with morphology
apperance of organism can be effected by lots of things
huge variation within closely related group of organisms
how does sexual dimorphism effect morphology
male and female look different so could be said to be different species when same
reproductive or biological species concept
if two organisms can reproduce to make fertile offspring they are the same species
definition of species
group of organisms with similar features that interbreed to produce fertile offspring
advantages of reproductive or biological species concept
overcomes sexual dimorphism
disadvantages of reproductive or biological species concept
populations of organisms may not interbreed because of where they live not because they are different species
second definition of species
group of organisms in which genes can flow between individuals
molecular phylogeny
breaking down code to find similarities and differences between DNA of species
ecological species model
based on ecological niche occupied by organism
negatives of ecological species model
niche definitons very and many organisms have more then one niche
mate recognition species model
based on unique fertilisation methods including mating behaviour
weaknesses of mate recognition species model
many species interbreed with organisms and produce fertile offspring but are different species
genetic species model
based of DNA evidence
positives and negatives of genetic species model
-advanced tech- used more
- have to work out what percentage of difference makes it not or same species
evolutionary species model
based on shared evolutionary shared history between organisms
weaknesses of evolutionary species model
no clear evolutionary pathway for any organsim
limitations of species models
finding evidence of species mating- mating programms expensive
can hybrids be own species or same
many organisms dont repduce sexually
fossil organisms have DNA hard to extract
what happens in DNA sequencing
all or part of the organisms base sequences are worked out
what does DNA sequencing lead to
DNA profiling
whats DNA profiling
looks at non coding areas of DNA to identify patterns
