1. Classification

2. Learning Objectives The biological classification of species
To include the taxonomic hierarchy of kingdom, phylum, class, order, family, genus and species AND domain.
The binomial system of naming species and the advantage of such a system
(i) the features used to classify organisms into the five kingdoms: Prokaryotae, Protoctista, Fungi, Plantae, Animalia to include the use of similarities in observable features in original classification.
(ii) the evidence that has led to new classification systems, such as the three domains of life, which clarifies relationships to include the more recent use of similarities in biological molecules and other genetic evidence AND details of the three domains and a comparison of the kingdom and domain classification systems.
The relationship between classification and phylogeny (covered in outline only at AS level)

3. Classification, phylogeny and taxonomy
Key definitions to match
The process of sorting living things into groups
up and learn!
The study of principles of classification
Taxonomy
The study of evolutionary relationships between organisms
Phylogeny
Classification

4. Early systems Aristotle – Plants or Animals Animals split into groups:
Live and move in the water
Live and move on land
Move through the air
Linnaeus and other scientists:
Observable features
Use of microscopes

5. Grouping species together – principles of classification
Classification –the grouping of organisms often on the basis of simple observable features
Taxonomy – the study of biological classification
Artificial classification
Divides organisms by what is useful at the time e.g. Colour, size, no of legs (analogous features)
Natural classification
Based on the evolutionary relationships between organisms and their evolutionary descent e.g. Shared features and derived from ancestors (homologous characteristics)

6. The concept of a species
Mule – result of horse & donkey mating. Hybrid.
Mule has 63 chromosomes & is nearly always infertile
A species is the basic unit of classification. Individuals of the same species are capable of breeding to produce living offspring which themselves are fertile
Horse –
64 chromosomes in a body cell, 32 chromosomes in a gamete
Donkey –
62 chromosomes in a body cell, 31 in a gamete

7. Naming species Carl Linnaeus – father of taxonomy
Binomial naming system
Uses two Latin names:
Generic (genus organism belongs to)
Specific (species that the organism belongs to)
There are rules!
Handwritten – Generic name starts with a capital, both parts underlined.
In type – in italics, generic name starts with a capital

8. The five kingdoms
Can you name them?

9. Kingdom Examples Main Features Prokaryotae Protoctista Fungi Plantae
bacteria
Single cell no nucleus peptidoglycan cell wall
Less than 5μm
Protoctista
Algae, protozoa such as malaria
Eukaryotic cells often single cells or simple organisms, often live in water
Fungi
Yeast, mushrooms, mould
Eukaryotic cells, chitin cell walls, saprotrophic nutrition using hyphae, single or multicellular. No photosynthesis
Plantae
Mosses, ferns, flowering plants, conifers
Eukaryotic cells, multicellular, cellulose cell walls, autotrophs which photosynthesise, contain chlorophyll. Store starch
Animalia
Nematodes, (roundworms) fish, insects, mammals
Eukaryotic cells, heterotrophic nutrition, multicellular, no cell wall

10. Ordering taxonomic ranks – using eight taxa
Do I have Domain
King Kingdom
Prawn Phylum
Curry Class (e.g. Mammals)
Or Order
Fat Family
Greasy Genus
Sausages Species
Number of similarities
Largest group
Distant ancestor
Smallest
group
Recent ancestor

11. KINGDOM
Protoctista
PHYLUM
Euglenophyta
CLASS
Euglenophyceae
ORDER
Euglenales
FAMILY
Euglenidae
GENUS
Euglena
SPECIES
Euglena gracilis
KINGDOM
Animalia
PHYLUM
Chordata
CLASS
Mammalia
ORDER
Primates
FAMILY
Hominidae
GENUS
Gorilla
SPECIES
Gorilla gorilla

12. June 2010 F212

14. Phylogeny
The study of how closely different species are related. Grouping based in evolutionary relationships and evolutionary history
A species is the smallest group that share a common ancestor
Common ancestor of humans and chimpanzees

15. Classifying organisms based on their phylogeny is known as cladistics

16. Molecular Evidence DNA Comparison of DNA sequences in common genes
Cytochrome C
A protein used in respiration.
All organisms except chemosynthetic organisms must respire so therefore contain this protein.

17. DNA and protein analysis can give evidence for phylogenies
The lengths of the branches in this tree are drawn proportional to the number of differences in the primary sequence.
The tree clearly reveals the three main kingdoms of eukaryotes: fungi, animals, and plants.
Such trees tend to agree closely with those constructed by evolutionary biologists using morphological data, and provide independent evidence of common descent.

18. LUCA Last Universal Common Ancestor
All life had one common ancestor – we know this because all life on earth uses the same genetic code to determine the amino acid sequence of its proteins

19. The three domains Carl Woese 1990
Ideas based on new evidence from detailed studies of RNA
Bacteria are fundamentally different from Archaea and the Eukaryotae

20. The three domain model
Within the eukaryota, the classification from Kingdom-species remains
UCMP History of Life
Animation re 3 domains

21. Bacteria Very different to everything else
Different cell membrane structure
Different structure to the flagella
Different enzymes to make RNA e.g. RNA polymerase
Naked DNA without proteins (histones)
Different method of DNA replication and building RNA

22. Archea Share some features with eukaryotes Similar enzymes to make RNA
Similar method of DNA replication and building RNA
Production of some proteins that bind to DNA
UCMP Intro to Archea

23. Bacteria
Archea
Eukarya
LUCA

24. Adaptations
Organisms need features which help them survive in the environment.
Natural selection is the mechanism that enables them to adapt.
Adaptations can be
Anatomical
Behavioural
Physiological

25. Anatomical Adaptations
Examples include
Size
Body shape
Camouflage
Mimicry
Colour
Surface covering

26. Behavioural Adaptations
Courtship rituals
Migration patterns
Hibernation
Innate and learned behaviour
Survival strategies such as playing dead
Possum playing dead

27. Physiological Adaptations
Making venoms and poisons
Making antibiotics
C4 plants use a different metabolic pathway to carry out photosynthesis to reduce water loss

28. Convergent Evolution
Some anatomical adaptations in different species are very similar although have arisen via different paths.
This creates Analogous Structures
Examples include
Fish and whale fins,
Octopus and mammalian eyes
Convergent evolution leads to different species appearing to have similar features because they are subject to similar selection pressures e.g. moving in water.

29. Marsupials and Placentals
Mammals that lay eggs Duck billed platypus/ Echidna
The division between marsupials and placentals occurred about 100MYA They have very different reproductive strategies but there is much evidence for convergent evolution between the 2 groups

32. Marsupial and Placental Moles
Both live in burrows and need to dig them with well adapted front limbs
Streamlined body shape
Soft fur reduces friction