Chapter 8 Page

Case Study – The seeds that poisoned Identification is important – knowing the difference between poisonous and harmless plants is important. Accurate identification is important for many reasons:- - personal safety - conservation - quarantine - forensics - medicine - agriculture and horticulture

 Whole specimen  Bits and pieces  Macroscopic evidence (hair, teeth, shells, fruit)  Microscopic evidence (cell features, DNA etc)  Indirect evidence: tracks, burrow etc

 Tracks, burrows, nests, scratchings, scats, hair and calls.  Field guides, reference collections, keys

(Scientists use observations and classification keys to classify organisms.) Keys: are used to make decisions about the presence (or absence) of certain features. Dichotomous Keys: are those keys that involve choosing between just two alternatives. Task: Using a dichotomous Key

 Identifying classes of objects involves giving them names.  Each different kind of organism or species has a unique scientific name.  Scientific names are binomial: the first part is the generic name; the second part is the specific name (species).  Identification can be at several levels and the most precise identification is at species level.  Homo sapien = scientific name!

 Video of the life a Carolus Linnaeus

 1758, new and uniform way of naming different kinds of organism by giving each species a two-part scientific name.  First part is the generic name or the name of the genus and begins with a capital letter.  The second part begins in lower case and identifies a particular member of the genus. It is known as the specific name or species.  Informative about the relationship between species. Q. How does the binomial system of classification differ from the polynomial system? (see page 225)

 Common names vary from language to language, however scientific names are universal.  The same common name is sometimes used to label different species.  Scientific names give an indication of the degree of relatedness.  Common names may be misleading suggesting relationships that are not valid.

 Many words come from greek and latin words.  Some come from other cultures or the person who identified the organism.

 Quick Check Questions 4 – 6

(Page ) Species can be defined in three different ways 1. Classic definition 2. Biological definition 3. Modern definition Biological Definition: taxanomic unit (group) consisting of organisms capable of mating and producing viable and fertile offspring. (Why does this definition struggle to define most microscopic organisms? Why is the ‘Modern definition’ more useful in such cases?

 The species is the basic unit of the living world.  Biologists who specialise in identifying, describing and classifying organisms are called taxonomists. Read Biologists at work, page 232

 Computer technology allows scientists to store, retrieve and organise the enormous amounts of data.  The application of computer technology to handle biological data is called bioinformatics.

Page 235 – 6  All species could be identified using a short stretch of DNA, that would serve as a unique identifier for that species.  For animals the barcode sequence is 650 bases from the COI gene that is found in the mitochondria of all cells.  Quick Check 7 – 10.

 Naming and describing each different kind or organism or species.  Organising closely related species into groups.  Combining these groups to form larger, more inclusive groups.

 Activity Manual pg 230

 Classification involves: 1.Naming and describing each different kind of organisms or species 2.Organising closely related species into groups (i.e Genus) 3.Combining these groups to form larger, more inclusive groups ◦ The basis on which groups are formed is known as a criterion

 Classifying or organising different kinds of organism into a smaller number of groups using objective and meaningful criteria produces benefits.  Predictions can be made about an item based on knowledge of its classification.

 The system of biological classification forms a nested hierarchy of levels from species to phylum.  Any level of classification – species, genus, etc – can be called a taxon (taxa).  The closer the evolutionary relationship between two organisms, the more similar their classification.

 Quick Check Questions 11 – 14  Activity Manual pg 222, 223, 224

 Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species

PROKARYOTESEUKARYOTES MONERAPROTISTAFUNGIPLANTAEANIMALIA Problems with this view!

DOMAIN BACTERIADOMAIN ARCHAEDOMAIN EUKARYA Complete Page 210 Activity Manual

 Defn: Phylogeny- classification reflecting evolutionary history  Defn: Cladistics – the grouping of organisms according to the number of derived characteristics they share ◦ Characters seen in a particular group can be identified as primitive or derived. ◦ Primitive features are features that were present in a common ancestor and so appear in all members of a group (i.e. pentdactyl limb (in whales/ man). ◦ Derived characters are advanced or modified features that evolved later and appear in some organisms only (i.e flipper).

Cladogram Diagram, based on cladistic study, that shows the inferred relationship between different groups of organisms.

 Page ; Student Workbook

 Quick Check Questions 15 – 17  Biochallenge pg 251  Chapter review pg 252, 253 and 254  Homework: Test Revision (Chapter 8)