Unit 3- Classification Flashcards
What is taxonomy
The science of classification
What is the order of hierarchy biologists use for classification?
KPCOFGS (kill phill cos our family gets spicy)
Kingdoms-phyla-classes-orders-families-genera-species
What did carolus linnaeus devise?
A hierarchy structure for classification in which different animals and bacteria etc were grouped into appropriate groups with no overlap
He also used this classification to devise a bionomial nomenclature (method of naming without confusion)
How are living organisms named unambiguously/
Generic name (capital and comes from the genus)+ specific name (lower case and comes from the species name)
What are the different definitions of species?
- morphology (need to know)
- ecological
- reproduction (need to know)
- evolutionary
Describe the morphology species definition: and what is its flaw
- members of the same species have similar characteristics, such as appearance, cell structures, biochemistry (metabolic pathways)
- can be misleading as some structures arise from common ancestors (homologous structures) and some structures look similar because they arose independently to do the same job (analogous structures)
What is the difference between an analogous and homologous structure?
Homologous structures look similar because they arose from a common ancestor
Analogous structures look similar but arose from different ancestors to perform the same job
Describe the ecological definition of a species:
- members of the same species have the same ecological niche (role in the ecosystem), eg how it lives, feeds,competes and reproduces
Describe the reproduction definition of a species: and pros and cons of this
- members of the same species can breed together in their natural environment to produce fertile offspring that cannot breed with other species
- easy to test out to see if 2 animals are the same species
- limitations are it cant be tested on extinct species and doesn’t work on asexually reproducing organisms
Describe the evolutionary definition of a species: pros and cons of this
- members of the same species that share a unique common ancestor with each other and not with any other species
- can be done easily by analysing the DNA sequences of 2 different species
- some genes can be transferred across species by horizontal gene transfer
What are phylogenetic trees?
Used to separate the different species to show where a common ancestor is
How can phylogenetic trees be interpreted?
- going forward in time they represent speciation
- going backwards they represent the most recent common ancestor
What 2 domains contain prokaryotes?
Archea and bacteria
What is meant by the word species?
When 2 organisms can interbreed to produce fertile offspring they are said to be the same species
Archea, bacteria and eukarya are the 3 domains what is different about Archea?
- extremophiles; they like to live in extreme conditions eg deep sea thermal vents
- they are also the nitrogen fixing and nitrifying bacteria (not technically bacteria)