Studied by 3 peopleState 4 reasons why classification is needed
To retrieve and store info
Identification
Predicting traits
Finding evolutionary origins
Why is classification useful for predictive values?
As traits are shared within a species
Why is classification useful for finding evolutionary origins?
If a group of organism share traits, links could be made to their origin
Name the taxa in order
Kingdom, Phylum, Class, Order, Family, Genus, Species
What is the name of the process of assigning organisms to taxa?
Taxonomy
What are the drawbacks to the taxa heirachy?
can be unclear how populations should be grouped into
disagreements on how to group species into larger groups
disagreements on the rank of taxa
Why do biologists have doubt about the heirachy of taxa?
Because taxonomy is arbitrary
What do biologists agree is the ideal means of classification follows?
Evolutionary relationships
Following the classification dependant on evolutionary relationships, what do all taxanomic groups share?
A common ancestor
What are the two criteria which need to be met to judge whether classification follows evolutionary relationships
Every organism that has evolved from a common ancestor is included in the taxanomic group
Every taxanomic group has evolved from a common ancestor
What do taxanomic groups share if they are descended from a common ancestor?
Similar characteristics
Why is it useful for Biologists when taxanomic groups have evolved from the same common ancestor?
Because they can predict characteristics within a group
What is the alternative to classifying according to taxa?
To classify using clades
Define clade
A group of organisms that have evolved from a common ancestor
What is the most objective way of classifying organisms into clades?
By comparing the base sequences of genes or amino acid sequences in proteins
If it using base sequences of genes or amino acid sequence is unavailable, what is another way of classifying organisms into clades?
Using morpholigical traits
Do all species only belong to one clade?
No
Explain how species can be part of different clades?
Smaller clades are nested in larger clades
What causes a change in DNA base sequences or amino acid sequences?
Mutations
What can we use to find when a set of species shared a common ancestor?
By finding the difference in number of mutations
What do we assume when using mutations to calculate when species have diverged from a common ancestor?
That mutations occur at a common rate
What is the process of dating divergences of species from common ancestors using mutations called?
The molecular clock
What is a cladogram?
A branching diagram that represents ancestor-descendant relationships
What about cladograms is useful when dating species?
It shows the sequence of divergence
What is a terminal branch?
The ends that represent an individual clade (species or group of species that are not subdivided)
What is a node?
The point at which a hypothetical ancestral species split to form two or more clades
What is a root?
The starting point of a cladogram that represents the hypothetical common ancestor of the entire clade
Give an example of a species that was re-classified after the use of base sequencing
The figwort family
What happened to classification after the use of base sequencing?
Many species were "re-classified”
Before 1977, what were the two recognised domains?
Prokaryote and eukaryote
After 1977, what was the prokaryote domain split into?
Archaea and eubacteria
Currently, what are the three domains?
Archaea, eubacteria, and eukaryotes
What are the components of te binomial naming system?
Genus + species
What is introgression?
The process by which hybrids form over many generations with an unequal distribution from each species
What is backcrossing?
When a hybrid species reproduces with a species of one of their parents
What is a clade also known as?
A monophyletic group
What is a sister group?
A group of closest relatives on a cladogram
What is an outgroup?
A group that is less closely related to others in a cladogram
What is a derived trait?
characteristics that have evolved recently
What is another name for a derived trait?
Apomorphic
What is a primative trait?
characteristics that evolved early
What is another name for a primative trait?
A plesiomorphic trait
What is phylogeny?
Study of the evolutionary past of species
What is phylogenetics?
Methods used to anylise relationships and study phylogeny
What are archaea?
Single celled organisms often found in extreme conditions
What are archaea found in extreme conditions called?
Extremophiles
What are the three types of extremophiles?
Halophiles: salt loving
Thermophiles: heat loving
Methanophiles: methane loving
Where are halophiles found?
In the dead sea or salt mines
Where are thermophiles found?
In hot springs or hydrothermal vents
Where are methanophiles found?
In landfills, marhses, paddy fields,…
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