AS Revision
Biodiversity: Classification
Session 1
Mrs Kavanagh
AS specification: Unit 2
Exam: 1 ½ hours
Film 1: Classification
Film 2: Characteristics
Classification into groups
The need for classification
3 domain v 5 kingdom
Key Words
Revision Lesson: Objectives and Outcomes
Define the term: classification
Become familiar with the 5 kingdom classification system
Understand the 3 domain classification system
Compare the 5 kingdom and the 3 domain systems
What is classification?
Classification is described as:
A process of naming and organising organisms into groups based on their characteristics and evolutionary history.
Classification is hierarchical.
The larger groups are split into groups of decreasing size.
The groups of
different organisms
are discrete.
Each group is called a taxon (plural, taxa) and are found at each taxonomic level.
Live Birth
Mammary Glands
Hair
Amniote Egg
Four Legs
Phylogenetic
5 kingdom
3 domain
Largest number of organisms
Smallest number of organisms
Decreasing number of organisms
What is the 3 domain classification system?
What do organisms in the same domain have in common?
Organisms in the same domain share the same ribosomal RNA
Every species has a binomial name. Which two taxa are used to make this name?��
Genus and species.
Biochemical evidence
led to the development
of the domain classification system.
Which of the following is not a domain?
Eukaryota
Archaea
Cnidaria
Bacteria
The taxonomical classification system is hierarchical with larger taxa subdivided into smaller taxa.
�Which of the following is the correct order of the taxa from largest to smallest?�
largest taxon
2nd largest taxon
3rd largest taxon
4th largest taxon
5th largest taxon
6th largest taxon
7th largest taxon
Kingdom
Phylum
Order
Class
Family
Species
Genus
3
5
or
How many domains do scientists use to classify organisms?
Kingdom
Species
or
Which taxon has the largest number of organisms?
Larger groups are split into groups of increasing size
or
Classification is hierarchical...what does this mean?
Larger groups are split into groups of decreasing size
Discrete
or
Which word describes the fact that one organism can only belong to one taxon?
Hierarchy
Exam Questions
In 1977, Carl Woese proposed the three-domain system, based on analysis of differences in the nucleotide sequences of 16S rRNA genes. Identify the domain to which the giant panda would belong. Give a reason for your answer. (2)
Eukaryota (1) Contains membrane bound organelles/DNA bound in envelope/80S ribosomes/multicellular (1)
Whales and dolphins belong to a single group of carnivorous, marine mammals called the cetaceans (order Cetacea). Cetaceans are comprised of three sub orders: Odontoceti (toothed whales, including sperm whales and dolphins), Mysticeti (baleen whales), and Archaeoceti (the extinct ancestors of modern whales).
There have been a number of theories, regarding the closest living relatives to the Cetaceans. The diagrams shown, illustrate two of these theories.
State the term used to describe diagrams, such as those shown above (1)
Phylogenetic tree/Evolutionary tree/Phylogenic (1)
Accept Cladogram but don’t accept Family tree/Pedigree diagram
With the exception of the cetacean, all the mammals in the table, belong to the
order Artiodactyla.
(i) Use the information in the table to explain whether Diagram A or Diagram B represents the currently accepted theory, regarding the closest living relative to the cetaceans (3)
(ii) Modern taxonomic classification combines Cetacea and Artiodactyla into a single order, the Cetiartiodactyla. Explain how this illustrates the ‘tentative nature’ of biological classification (2)
(iii) Both the common bottlenose dolphin (Tursiops truncates) and the killer whale (Orcinis orca) belong to a smaller taxonomic group of the sub-order Odontoceti, called the Delphinidae. Name the group in the taxonomic hierarchy to which the Delphinidae belong to (1).
Classification {may change/not fixed/not permanent} (1)
As more {information/knowledge/techniques} become available/OWTTE
Diagram B (1) Hippo closest relative/shares most recent common ancestor with the hippo (1) fewest differences/most similarities/or use of data (1)
Family (1)
The table opposite, gives some details of human classification, in hierarchical order.
Name the class and the family to which humans belong.
Class: _______________
Family: _______________
Taxon | Human |
Kingdom | Animalia |
| Chordata |
| Mammalia |
| Primates |
| Hominidae |
| Homo |
Species | sapiens |
Mammalia
Hominidae
The snow leopard, Panthera uncia, is an endangered species of big cat, found in the mountainous regions of central Asia.
�Complete the table, opposite, for the classification of the snow leopard.
Taxon | Human |
Kingdom | Animalia |
Phylum | Chordata |
| Mammalia |
Order | Carnivora |
| Felidae |
Genus | |
Species | |
Family
Class
Panthera
uncia
The sorting of living organisms, including humans. Into groups of manageable size, is called taxonomy or classification.
Describe and explain the principles underlying the modern classification (10).
Modern classification system aims to show how organisms are related through evolution.
Closely related organisms show more features/characteristics
A taxon is a group of organisms that share basic characteristics/example
{classification groups/taxa} are discrete and hierarchical
{taxa include} kingdom phylum class order family genus species
Corrects sequence of taxa
Hierarchy/sequence of taxa shows: kingdom – largest group, to species – smallest group
Organisms grouped into the kingdoms: animalia, plantae, fungi, Protoctista and prokaryotae
All have eukaryotic cells, except for prokaryotes
{Binomial system/genus and species} used to name organisms
Genus is a group of closely related species
Species is a group of organisms, that can interbreed to produce fertile offspring
{Biochemical methods/named method} compare similarities in DNA/proteins of different species
The greater the similarity, the more closely related to the species
Biochemical methods are reducing mistakes made, due to convergent evolution
Revision Lesson: Objectives and Outcomes
Define the term: classification
Become familiar with the 5 kingdom classification system
Understand the 3 domain classification system
Compare the 5 kingdom and the 3 domain systems