Today we are covering from the specification What

Today we are covering from the specification:

What is classification? • Organising living organisms into groups • We need to do this as scientists have already named around 1. 8 million different living organisms. Look at the specimens and arrange them into groups. • How did you decide on the groups? • What different methods of grouping can you think of?

What is a species?

What is a species? • A group of organisms that are similar to each other but different from members of other species. • Similar genes, similar physical and biochemical characteristics • Similar developmental patterns and immunological features • Occupy the same niche

• Members of the same species can breed with each other to produce living, fertile offspring • A full set of genes from any individual can be combined with that of another individual if they are of the same species.

What is a species? • Members of the same species can breed with each other to produce living, fertile offspring • Rarely, different species can interbreed but their offspring are infertile.

Mules and Hinnies

Liger (male lion and female tiger)

Tigon (female lion and male tiger)

How do we name a species? • Used to be due to certain features of the organism • No continuity across the world • 200 years ago Linnaeus (a Swedish botanist) came up with a universal system

The Binomial System • Uses Latin or Greek names • The first name is the generic name and this is the genus to which the organism belongs – (Similar to the surname of a person) • The second name is the specific name and this is the species. – (Similar to the first name of a person)

Canis lupus Equus caballus Protea caffra

The Binomial System: Rules • The specific name is never shared with another species within the genus. • The names are printed in italics or underlined if hand written. • The first letter of the generic name is capitalised, and the specific name is not.

Principles of classification • The grouping of species is called classification, whereas the practice of biological classification is called taxonomy.

Types of classification Artificial classification: • Divides organisms by physical characteristics, such as size or number of legs. • Describes by the same function, not the same evolutionary origin. • What are the problems with this?

Types of classification Natural classification: • Based upon evolutionary relationships. • Classifies species using shared features derived from their ancestors. • Arranges the groups into a hierarchy – groups contained within larger groups with no overlap

Taxonomy Each group within a biological classification is called a taxon (pl. taxa). The largest is the kingdom.

Taxonomy • Each group within biological classification is called a taxon. • The largest is the kingdom. • The largest group in a kingdom is a phylum.

Taxonomy • Each group within biological classification is called a taxon. • The largest is the kingdom • The largest group in a kingdom is a phylum. • Within phyla there are classes.

• • Classes are then sub-divided into orders Orders are divided into families Each family is divided into genera (sing. = genus) Each genus is divided into species

King Prawn Curry Or Fat Greasy Sausages? Keep Ponds Clean Or Frogs Get Sick! Rank Kingdom Phylum Class Pin mould Fungi Zygomycota Zygomycetes Sweet Pea Plantae Angiospermophyta Dicotyledona Tiger Animalia Chordata Mammalia Order Family Genus species Murolales Muroraceae Murcor mucedo Rosales Fabaceae Lathyrus odoratus Carnivora Felidae Felix tigris

Phylogeny • This is the evolutionary relationship between organisms. • The phylogeny reflects the evolutionary branch that led to the organism. • Usually shown as a tree like diagram, a phylogenetic tree.

Homework Complete the following sections of your Unit 2 booklet to hand in on Friday: - Natural selection and genetic diversity - Investigating variation

To do: • Create your own model of a phylogenetic tree • Arrange the objects into an evolutionary tree (make sure you follow the rules!) • Once you have finished, you can glue the pictures down. . . • Draw lines in between! • Be prepared to justify your choices. 20 minutes

Problems defining species… • • What should you do about different breeds of dog? Species are not fixed Many species are extinct Some species are sterile…

Exam Questions

The mule problem…

Learning Check! Self assessment 1. a. Green Monkey (1 mark) Because it’s the closest to humans on the tree. (1 mark) b. Pig (1 mark) 2. A group of similar organisms (1 mark) able to reproduce to give fertile offspring. (1 mark) 3. Max 5 marks available, 1 mark for each correct answer Kingdom Phylum Class Order Family Genus Species Animalia Chordatia Mammalia Primates Homidinae Homo sapiens 4. Max 3 marks available. E. g You can’t study the reproductive behaviour of extinct species (1 mark) Some species reproduce asexually (1 mark) There are practical and ethical issues involved in studying some. reproductive behaviour (1 mark)

You should be able to… • Define what we mean by a species • Explain the system of naming species • Outline the principles of classification – Natural classification and artificial • Explain what is meant by taxonomy and phylogeny • Be able to interpret a phylogenetic tree