1. Marine Biology St. Dominic HS Ms. Kraker

2. How did classification begin? Biologists want to better understand organisms so they organize them into groups based on similarities – classification. Taxonomy – the branch of biology that groups organisms based on different characteristics.

3. Aristotle’s system Two groups: Plants and Animals Plants subdivided into shrubs, herbs, and trees. Animals subdivided into land, air, and water.

4. Linnaeus’s System In the 18 th century, Linnaeus grouped organisms based on physical and structural similarities. His system is the basis of modern classification systems.

5. Binomial Nomenclature A two-word naming system that identifies the genus and species of an organism. Genus – a group of similar species. Scientific names are Latin, italicized or underlined when written. The genus is capitalized and the species name is not.

6. Binomial Nomenclature cont. Organisms may have many common names, but only have one scientific name that does not change.

7. Modern Taxonomy Biologists try to identify evolutionary relationships by comparing structures and chemical makeup. Classifications provides a framework for studying relationships between living and extinct species.

8. Modern Taxonomy cont. Classification allows organisms to be easily identified. A dichotomous key is used to identify organisms.

9. How are organisms classified? Organisms are ranked starting in very broad categories down to very specific ones. Species Genus Family Order Class Phylum Kingdom Domain

10. Species - sapiens Genus - Homo Family - Hominidae Order - Primata Class - Mammalia Phylum - Chordata Kingdom - Anamaila Domain - Eukarya

11. Arthropod- rigid external skeleton, paired and jointed legs, segmented body, and are bilaterally symmetrical. Largest animal phylum: includes horseshoe crabs and other crustaceans, spiders, scorpions, centepides, and insects. Crustacean- an arthropod with an exoskeleton (or hard outer shell), jointed limbs, and two pairs of antennae. Includes crabs, lobsters, shrimps, and crayfish. Considered a subphylum. Scientific Classification What That Classification Means KingdomAnimalia A living organism that feeds on organic matter, typically having specialized sense organs and nervous system and able to respond rapidly. PhylumArthropoda A large division of Articulata, embracing all those that have jointed legs. It includes insects, arachnida, pychnogonida, and crustacea. ClassMalacostraca A large class of crustaceans that includes crabs, shrimps, lobsters, isopods, and amphipods. They have compound eyes, which are typically on stalks. OrderDecapoda An order of crustaceans that includes shrimps, crabs, and lobsters. They have five pairs of walking legs and are typically marine. FamilyGrapsidae The square-backed crabs, a family of decapod crustaceans in the section Brachyura. Genus Hemigrapsus The shore crab. They have a rectangular shaped carapace up to 2 inches wide and with three "teeth" along the edge behind each eye. Species Sanguineus Asian shore crab Terms that are Helpful to Know