2.7 - Biodiversity and Classification Flashcards
What is meant by ‘phylogenic’?
Reflecting revolutionary relatedness
What is a phylogenic tree?
A diagram showing descent, with living organisms at the tips of the branches and ancestral species in the branches and the trunk, with branch points representing common ancestors. The length of the branches indicate the time between branch points.
The further up the diagram you go, the further forward in time, so the species at the top exist now. Those in the trunk and branches are no longer alive.
What is the ‘taxonomy’?
The identification and naming of organisms.
What is ‘classification’?
Putting items into groups.
What is ‘hierarchy’?
A system of ranking in which small groups are nested in components of larger groups.
What is a taxon?
Any group within a system of classification.
Name the hierarchy of biological classification with an example for each.
Domain - Eukaryota
Kingdom - animalia
Phylum - chordata
Class - mammalia
Order - primates
Family - Hominidae
Genus - homo
Species - sapiens
What happens when you move down the biological hierarchy?
From domain to species, organisms in a taxon are more closely related.
What happens when you move up the biological hierarchy?
From species to domain, organisms in a taxon are less closely related.
Why do we need a classification system?
- it allows us to infer evolutionary relationships between organisms
- we can predict characteristics of animals from its species
- makes communication between scientists easier globally
Why is the classification system described as being tentative in nature?
The classification system depends on our current knowledge. Any system we use is tentative and may be altered as our knowledge advances.
What is ‘domain’?
Largest taxon and all living things belong in 1 of the 3 domains.
How has classification in domain changed over time?
Originally defined on the bases of rRNA base sequences, more modernly methods of analysis consider similiarities in the DNA sequence.
What are the 3 domains?
Eubacteria
Archaea
Eukaryota
What are eubacteria?
These are familiar bacteria such as E.coli and salmonella. They are prokaryotes.
What are archaea?
These are bacteria but have unusual metabolisms, for example generating methane. They live in marginal environments and are also all prokaryotes.
What are eukaryota?
Plantae, animalia, fungi and protoctista
What are kingdoms?
5 kingdom system classifies organisms on the basis of their physical appearances
What are the 5 kingdoms?
Prokaryota, protoctista, fungi, plantae and animalia
What are ‘phylum’?
Sub group of a kingdom, members of each phylum have a distinct body plan (eg chordata = vertbrates)
What is a ‘class’?
Sub group of phylum (eg mammalia forms under the phylum chordata)
What is an ‘order’?
Sub group of a class (eg lepidoptera is the order containing butterflies and moths, in the class insecta)
What is a ‘family’?
A group within an order. Flower families are most familiar such as the rose family (rosaceae)
What is the genus?
A group of organisms for example the genus Panthera, containing lions and tigers