“Grouping together items into categories based on a set criteria”

“Grouping together items into categories based on a set criteria”

Group Activity

-get yourselves into groups of 4

-Brainstorm and list 20 domesticated animals

-your job is to group your list of animals into different categories

-you MUST:

-use more than three categories

-be prepared to describe the criteria you used for your groupings

“Systematic grouping of organisms into categories on the basis of defined criteria”

Taxonomy

“the science of classifying ALL organisms”

-Very general

- millions of species?

- how to start classifying?

• behaviour

• where they live/habitat

• appearance and characteristics

(MORPHOLOGY)

Mosquitoes –50 species

Seed plants – 260 000 species

Challenges to Classification?

- Yesterday?

• Variation:

o over space and time

o among individualsEvolution

DNA

The biggest classification problem has always been consistency

• Ancient Greece

(Coles notes)

Aristotle

(384 – 322 BC)

-First to introduce classification and binomial definition

- classify ALL LIVING things (Historia Animalium)

- blood/no blood, water/land

-Hierarchical; each organism fixed position

• Humans

• Animals

• Plants

Great Chain of

Being

Issues?

-complex plants below simple animals

-little genetic relationship

-Evolution?

-Virtually no innovation to Aristotle’s work till the 16th century

-virtually 2000 years!!!

-shamans/Aboriginal healers/Andrea Cesalpino

• Irregularity amongst names

-needed agreed upon set of naming guidelines

-Scientific naming

- the father of taxonomy

- 2 key contributions to classification:

1. Consistent way of grouping species according to morphological similarities

2. Naming system

- 2 parts

1. Genus species; capitalized, italicized

2. species specific species; italicized

Systema Nature (1735)

Gerbera hybrida

-standard naming system for all organisms

-simple

-convenient

-flawed

Ursus americanus

Ursus maritimus

Phascolarctus cinereus

Share many characteristics

Share few characteristics

kingdom

phylum

class

order

family

genus

species

Ranks based on shared

characteristics

-each level = taxon

General/fewer similarities

Specific/moreSpecific/more

Animalia

Chordata

Mammalia

Primates

Hominidae

Homo

sapiens

- refined into subcategories

“structure in which a large set of items is broken down into smaller subset, ultimately leading to the smallest available classification unit.”

- series of branching two-part statements used to identify organisms

- large set broken down to smallest classification unit

- larger number of species, the more specific questions become

Dichotomous Key practicePage 18

Textbook

Difficulties?

• number of species

• distinguishing characteristics are internal

• agreeing on criteria

Activity

Get into groups of 4-6

Within your group you will be creating your own dichotomous key

The subject of your key will be classifying each member of your group

Remember dichotomous keys “are a series of branching two-part statements used to identify organisms.”

Therefore your keys need to contain multiple steps and be specific

When, finished, you must demonstrate the viability of your key to Mr. Faulhafer for assessment

Complete questions 5 and 8 on page 20 of textbook