Scientific Classification SOL BIO: 7 a-e

The student will investigate and understand bases for modern 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 AGroup 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 1 st method of classification He divided all living things into 2 major groups

Aristotle ( BC)

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 ( )

MODERN CLASSIFICATION SYSTEM Organisms are grouped together on the basis of: Similarity in structure Felis domesticusFelis 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

Kingdom – largest group 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.

Kingdom Phylum Class Order Family Genus Species

K__________ p__________ c_________ o___________ f________ g_________ s________. Kings play chess on fine gold sets.

K__________ p__________ c_________ o___________ f________ g_________ s________. King Phillip came over for great soup.

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 italics Ex. 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 hannah Common 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.