Classification of Organisms Flashcards
What is phylogeny?
Study of evolutionary history/relationships of groups of organisms
Tells us who is related to whom and how closely related
Wha shows how all organisms evolved from a shared common ancestors (relatives)?
On a phylogenetic tree
What does the phylogenetic tree?
Shows the relationship between members of the Homindae family (great apes and humans)
What does the first branch of the phylogenetic tree?
Represents a common ancestor of all family members
This ancestor is now extinct
Orangutans were the first group to diverge (evolve to become a different species) from common ancestor
What does each of the following branch of the phylogentic tree show?
Represents another common ancestor from which a different group diverged
Gorillas diverrged next, then humans closely followed by bonbos and chimpanzees
What does closely related species in phylogentic tree show?
Diverged away from each other most recently
e.g Humans and chimpanzees are closely related as they diverged very recently.
You can see as branches are close
Diagram of phylogentic tree
What is taxonomy?
Science of classification
involves naming and organising species into groups to identify and study
takes into acounnt of phylogency where classifying organisms due to their evolutionary relationships
How many levels of groups they are to classify the organisms?
Eight
What are the eight groups classifying organisms are?
Taxa
What is each of the eight levels of classification called?
A taxon
What are the groups arranged in?
Hierarchy
What are the properties of a hierachy?
Largest group at top and smallest group at bottom
Organisms can only belong to one group at each level in hierachy - no overlap
What are organisms first sorted into by?
Three large groups called domains
Eukarya
Bacteria
Archea
What are related organisms in the domain sorted into?
Kingdoms
e.g all animals into animal kingdom
then closed related into phylum
then class and so on in hierarchy
What is the pattern as you move down the hierarchy?
More groups at each level but fewever organisms in each group
Organsism in each group also become more closely related
What does the hierarchy end with?
Species
Groups that contain only one type of organisms e.g humans , E.coli
What is a species?
Group of similar organisms able to reproduce to give fertile offspring
How do scientists constantly update the classification system?
Discoveries about new species and new evidence about known organisms
e.g DNA sequence data
What is bionminal system?
Nomenclature (naming system) used for classification
What is the first part of the name?
Genus and it has a captial letter
What is the second part of the name?
Species name and begins with lower case letter
Characteristic of bionminal naming system
Either in italics
Homo sapiens
or
underlined (handwritten)
Homo sapiens
Why is the bionominal system help?
To avoid the confusion of common names
e.g over 100 different plant species are called raspberries and one species of buttercup has over 90 different common names
Why is courtship behaviour carried out?
Organisms to attract a mate of the right species
Examples of courtship behaviour:
- Releasing chemicals or quite complex e.g series of displays
What does it mean that courtship behaviour is species specific?
Only members of the same species will do and respond to that courtship behaviour
Allows members of the same species will recongnise each other
prevent interbreeding
Making reproduction more successful (mating with wrong species won’t produce fertile offspring)
Can courtship behaviour classify organisms?
Yes
Behaviour is species specific
What happens with courtship behaviour and how closely related an organism is?
More closely related the species is
More similar their courtship behaviour
Examples of courtship behaviour of fireflies
Gives off pulse of light
Pattern of flashes is specific to each species
Examples of courtship behaviour with crickets
Mkae sounds that are similar to Morse code
Code is different for different species
Examples of courtship behaviour with peacocks:
Male peacocks show off their colourful tails
Tail pattern is only founf in peacocks
Example of courtship behaviour with butterflies
Male butterflies use chemicals to attract females
Only those of the correct species respond
The brook trout is another member of the Salmonidae family
Rarely, a brook trout and a brown trout are able to produce offspring known as tiger trout
Tiger trout are unable to reproduce
Explain how you know brook trout and brown trout are different species
Unable to produce fertile offspring
As they mate they produce infertile offspring
Even when groups of extinct organisms have left fossil records
It is difficult to distinguish different species
Suggest two reasons why:
- Fossils records can never reveal whether individuals could successfully mate
- Not all features observed ( no biochemical record) so comparison between individuals is hard to make
Why is it difficult to classify organism as a distinct species?
Species chane and evolve over time
sometimes developing into different types of species
Fossils incomplete
Does the fact that fertile mules ocassionally occur make a mule a distinct species?
Give reasons for your answer
No it does not
Fertile females mules are known
Interbreeding is impossible
Event is rare considered abnormal - wrong to draw conclusions
Donkey and horses are recongised as separate species
Name all the eight levels
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Acronym
Dominant
Kinky
People
Can
Often
Find
Good
Sex
What is a taxon?
Each level in hierarchy
Advantages of courtship behavior
- Recongnition of the same species
- Stimulate the release of gametes
- Recognise the opposite sex/gametes
- Indicate sexual mating
