Scientific Classification

SOL BIO: 7 a-e

SOL BIO: 7 a-e The student will investigate and understand

bases formodern classification systems. Key concepts include:

a) structural similarities among organisms;

b) fossil record interpretation; c) comparison of developmental stages

in different organisms; d) examination of biochemical

similarities and differences among organisms; and

e) systems of classification that are adaptable to new scientific discoveries.

CLASSIFICATION the grouping of organisms by

similarities Biological classifications are

based on how organisms are related.

Group A Group B

Taxonomy the branch of biology

concerned with the grouping and naming of organisms; the study of classification

Taxonomy Organisms are

classified into a hierarchy of groups and subgroups based on similarities that reflect their relationships over a period of time.

Cladogram or Phylogenic Tree

A branching, treelike diagram in which the endpoints of the branches represent specific species of organisms.

It is used to illustrate phylogenetic relationships and show points at which various species have diverged from common ancestral forms.

HISTORY: Aristotle- developed the 1st

method of classification

He divided all living things into 2 major groups

Aristotle (384 - 322BC)

Aristotle’s Groups He divided all living things into 2

major groups 1. Plants

classified by size and structure

2. Animals classified by habitat (where they

lived)

HISTORY: Aristotle Problems with his system:

Frogs live in both water and on land

HISTORY: Aristotle Problems with his system:

Bats, birds and flying insects were grouped together

HISTORY: Carolus

Linnaeus- developed the modern system of classification

Father of Taxonomy

Carolus Linnaeus (1707-1778)

MODERN CLASSIFICATION SYSTEM Organisms are grouped

together on the basis of: Similarity in structure

Felis domesticus

Felis rufusPanthera leo

Similarity in structure

Canis lupus

Similarity in structure

Canis latrans

Similarity in structure

Canis domesticus

Organisms are grouped together on the basis of:

Similarity in genetic makeup (biochemistry)

Similarities among organisms on the structural and metabolic levels are reflected in the large degree of similarity in proteins and nucleic acids of different organisms.

Diversity is the product of variations in these molecules.

Organisms are grouped together on the basis of:

Similarity of embryonic development

Organisms are grouped together on the basis of:

Similarity in evolutionary history

Phylogeny: the evolutionary

history of a species based on comparing relationships between species using the fossil record

Organisms are grouped together on the basis of:

Similarity in behavior

Classification is based on close evolutionary relationships of organisms.

Organisms classified in the same taxa (pl.) (taxon, sing.) share a common ancestry. They have evolved from the same common ancestral organism.

Evolutionary Relationships

Classification is hierarchal

each successive level is smaller and more closely related than the one before it

Domain- highest level; bacteria, archaea & Eukarya

Kingdom – 6 Kingdoms Phylum (sing.)

Phyla (pl.)(Plants don’t have phyla, they have divisions.)

Class Order Family Genus Species

These two taxa make up the scientific name.

D__________ k__________ p__________ c_________ o___________ f________ g_________ s________.

Dapper Kings play chess on fine gold sets.

Binomial Nomenclature

Binomial nomenclature is a standard way of identifying a species with a scientific two-word name.

The first word is the genus name and the second the species name.

Binomial Nomenclature Scientific name - 2 Latin names - Genus and species - Capitalize the first letter of the

genus - Do NOT capitalize the species - ALWAYS underline or use

italicsEx. Homo sapiens

Binomial Nomenclature

Scientific Name: Homo sapiens

Common Name: Daddy & Olivia

Binomial Nomenclature

Scientific Name: Rudbeckia hirta

Common Name: Gloriosa daisy

or Black-eyed Susan

Binomial Nomenclature

Scientific Name: Pinus virginianis

Common Name: Virginia Pine

Binomial Nomenclature

Scientific Name: Harmonia axyridis Common Name: Asian Ladybug

Binomial Nomenclature

Scientific Name: Ophiophagus hannahCommon Name: King Cobra

Species organisms that belong to the

same species can mate AND produce FERTILE offspring.

Horses and donkeys can mate. They produce a mule.

Mules are INFERTILE

+ =

Lions and tigers can mate. They produce a liger.

Ligers are INFERTILE

+ =

Why use scientific names? Common names do not indicate how

organisms are related or classified.

Common names can be misleading.

(e.g., seahorse, weeping willow)

Organisms with more than one common name leads to mass confusion.

Why Latin? Latin is no longer spoken, and

therefore, does not change as spoken languages do.

So, scientific names remain the same forever.