Classification Basics

Question 1

What is the classification?

Answer 1

Classification is the act of ARRANGING ORGANISMS into GROUPS based on their SIMILARITIES and DIFFERENCES.

This makes it EASIER for scientists to IDENTIFY and to STUDY them.

Question 2

What is Taxonomy?

Answer 2

Taxonomy is the STUDY of classification

Question 3

There are a few different classifications systems in use, but they all involve placing organisms into groups in a TAXONOMIC HIERARCHY:

> There are EIGHT LEVELS of groups …

Answer 3

called TAXONOMIC GROUPS used in classifications.

Question 4

There are a few different classifications systems in use, but they all involve placing organisms into groups in a TAXONOMIC HIERARCHY:

> SIMILAR ORGANISMS are first sorted into one of THREE very LARGE GROUPS…

Answer 4

called DOMAINS, e.g. animals, plants and fungi animals are in the Eukarya domain.

Question 5

There are a few different classifications systems in use, but they all involve placing organisms into groups in a TAXONOMIC HIERARCHY:

> SIMILAR ORGANISMS are then sorted into SLIGHTLY SMALLER GROUPS …

Answer 5

called KINGDOMS, e.g, all animals are in the animal kingdom

Question 6

There are a few different classifications systems in use, but they all involve placing organisms into groups in a TAXONOMIC HIERARCHY:

> SIMILAR organisms from that kingdom are then grouped into a ….

Answer 6

PHYLUM.

SIMILAR organisms from each phylum are then grouped into a CLASS, and SO ON down the eight levels of taxonomic hierarchy.

Question 7

As you move DOWN the hierarchy…

Answer 7

there are MORE GROUPS at each level but FEWER ORGANISMS in each group.

Question 8

The hierarchy ENDS with…

Answer 8

SPECIES-the groups that contain ONE TYPE OF ORGANISM (e.g. humans, dogs, E.coi and about 50 million other living species).

Question 9

Organisms can be placed into …

Answer 9

one of FIVE KINGDOMS.

Question 10

Kingdom: Prokaryote

Answer 10

Example: bacteria

Features: Prokaryotic, unicellular (single celled), no nucleus, less than 5 um

Question 11

Kingdom: Protocista

Answer 11

Example: algae,protozoa

Features: Eukaryotic cells, usually live in water, single-celled or simple multicellular organisms.

Question 12

Kingdom: Fungi

Answer 12

Examples: Moulds,Yeasts,mushrooms

Features: Eukaryotic, chitin cell wall,Saprotrophic (absorbs substances from dead or decaying organisms), single-celled or multicellular organisms.

Question 13

Kingdom: Plantae

Answer 13

Examples: mosses,ferns,flowering plants

Features: Eukaryotic, multicellular, cell walls made of cellulose, can photosynthesise, contain chlorophyll , autotrophic (produce their own food).

Question 14

Kingdom: Animilia

Answer 14

Examples: nematodes (roundworms), molluscs, insects, fish, reptiles, birds, mammals

Features: Eukaryotic, multicellular, no cell walls, heterotrophic (consume plants and animals)

Question 15

The Binomial naming system is used in ….

Answer 15

Classification

Question 16

The NOMENCLATURE (naming system) used for classification is called the ….

Answer 16

Binomial system.

All organisms are given ONE internationally accepted scientific NAME in LATIN that has TWO PARTS.

Question 17

The FIRST PART of the latin name is the …

Answer 17

Genus and has a capital letter.

Question 18

The SECOND part of the latin name is the…

Answer 18

SPECIES name and begins with a lower case letter.

E.g. Using the binomial system humans are Homo sapiens.

Names are always witten in italics

Question 19

Why is the binomial system important?

Answer 19

The binomial system helps avoid the confusion of using COMMON NAMES.

E.G. over 100 different plant species are called RASPBERRIES and one species of buttercup has over 90 different common names.

Question 20

Phylogeny tells us about the …

Answer 20

Evolutionary history of organisms.

Question 21

What is PHYLOGENY?

Answer 21

Phylogeny is the study of the EVOLUTIONARY HISTORY of groups of organisms.

Phylogeny tells us whos related to whom and how CLOSELY RELATED they are.

Question 22

What does the evolutionary tree show in page 119?

Answer 22

The tree shows the RELATIONSHIP between the members of the HOMINIDAE FAMILY (great apes and humans).

The FIRST BRANCH point represents a COMMON ANCESTOR of ALL the family members. This ancestor is now EXTINCT.

Orangutans were the first group to DIVERGE (evolve to become a different species) from this common ancestor.

Question 23

What do the other branches show, in page 119?

Answer 23

Each of the following branch points represents ANOTHER COMMON ANCESTOR from which a different GROUP DIVERGED.

Gorillas diverged next, then humans closely followed by bonobos and chimpanzees.

Question 24

According to PHYLOGENETICS, a species is the smallest group that shares a COMMON ANCESTOR-in other words…

Answer 24

The end of the branch on a phylogenetic tree.

Question 25

Give an example on two species closely related to each other that have diverged from each other recently.

Answer 25

Humans and Chimpanzees are Closely related, as they diverged very recently.

You can see this because their branches are close together.

Humans and Oragutans are more DISTANTLY related, as they diverged longer ago, so their branches are further apart.

Question 26

Classification systems now take into account PHYLOGENY when arranging organisms into GROUPS.

Classifying organisms in this way is known as ….

Answer 26

Cladistics