Classification of Organisms

Question 1

What is phylogeny?

Answer 1

Study of evolutionary history/relationships of groups of organisms

Tells us who is related to whom and how closely related

Question 2

Wha shows how all organisms evolved from a shared common ancestors (relatives)?

Answer 2

On a phylogenetic tree

Question 3

What does the phylogenetic tree?

Answer 3

Shows the relationship between members of the Homindae family (great apes and humans)

Question 4

What does the first branch of the phylogenetic tree?

Answer 4

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

Question 5

What does each of the following branch of the phylogentic tree show?

Answer 5

Represents another common ancestor from which a different group diverged

Gorillas diverrged next, then humans closely followed by bonbos and chimpanzees

Question 6

What does closely related species in phylogentic tree show?

Answer 6

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

Question 7

Diagram of phylogentic tree

Answer 7

Question 8

What is taxonomy?

Answer 8

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

Question 9

How many levels of groups they are to classify the organisms?

Answer 9

Eight

Question 10

What are the eight groups classifying organisms are?

Answer 10

Taxa

Question 11

What is each of the eight levels of classification called?

Answer 11

A taxon

Question 12

What are the groups arranged in?

Answer 12

Hierarchy

Question 13

What are the properties of a hierachy?

Answer 13

Largest group at top and smallest group at bottom

Organisms can only belong to one group at each level in hierachy - no overlap

Question 14

What are organisms first sorted into by?

Answer 14

Three large groups called domains

Eukarya

Bacteria

Archea

Question 15

What are related organisms in the domain sorted into?

Answer 15

Kingdoms

e.g all animals into animal kingdom

then closed related into phylum

then class and so on in hierarchy

Question 16

What is the pattern as you move down the hierarchy?

Answer 16

More groups at each level but fewever organisms in each group

Organsism in each group also become more closely related

Question 17

What does the hierarchy end with?

Answer 17

Species

Groups that contain only one type of organisms e.g humans , E.coli

Question 18

What is a species?

Answer 18

Group of similar organisms able to reproduce to give fertile offspring

Question 19

How do scientists constantly update the classification system?

Answer 19

Discoveries about new species and new evidence about known organisms

e.g DNA sequence data

Question 20

What is bionminal system?

Answer 20

Nomenclature (naming system) used for classification

Question 21

What is the first part of the name?

Answer 21

Genus and it has a captial letter

Question 22

What is the second part of the name?

Answer 22

Species name and begins with lower case letter

Question 23

Characteristic of bionminal naming system

Answer 23

Either in italics

Homo sapiens

or

underlined (handwritten)

Homo sapiens

Question 24

Why is the bionominal system help?

Answer 24

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

Question 25

Why is courtship behaviour carried out?

Answer 25

Organisms to attract a mate of the right species

Question 26

Examples of courtship behaviour:

Answer 26

• Releasing chemicals or quite complex e.g series of displays

Question 27

What does it mean that courtship behaviour is species specific?

Answer 27

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)

Question 28

Can courtship behaviour classify organisms?

Answer 28

Yes

Behaviour is species specific

Question 29

What happens with courtship behaviour and how closely related an organism is?

Answer 29

More closely related the species is

More similar their courtship behaviour

Question 30

Examples of courtship behaviour of fireflies

Answer 30

Gives off pulse of light

Pattern of flashes is specific to each species

Question 31

Examples of courtship behaviour with crickets

Answer 31

Mkae sounds that are similar to Morse code

Code is different for different species

Question 32

Examples of courtship behaviour with peacocks:

Answer 32

Male peacocks show off their colourful tails

Tail pattern is only founf in peacocks

Question 33

Example of courtship behaviour with butterflies

Answer 33

Male butterflies use chemicals to attract females

Only those of the correct species respond

Question 34

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

Answer 34

Unable to produce fertile offspring

As they mate they produce infertile offspring

Question 35

Even when groups of extinct organisms have left fossil records

It is difficult to distinguish different species

Suggest two reasons why:

Answer 35

• 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

Question 36

Why is it difficult to classify organism as a distinct species?

Answer 36

Species chane and evolve over time

sometimes developing into different types of species

Fossils incomplete

Question 37

Does the fact that fertile mules ocassionally occur make a mule a distinct species?

Give reasons for your answer

Answer 37

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

Question 38

Name all the eight levels

Answer 38

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Question 39

Acronym

Answer 39

Dominant

Kinky

People

Can

Often

Find

Good

Sex

Question 40

What is a taxon?

Answer 40

Each level in hierarchy

Question 41

Advantages of courtship behavior

Answer 41

• Recongnition of the same species
• Stimulate the release of gametes
• Recognise the opposite sex/gametes
• Indicate sexual mating