Taxonomy

Environmental Ed. 1

Taxonomy

• The science of naming and classifying organisms.

Linnaean taxonomy

• Named after Swedish botanist Carolus Linnaeus

• Classifies organisms based on their physical and structural similarities

• Uses Binomial Nomenclature

Binomial Nomenclature

• System that gives each species a two-part scientific name using Latin words.

• First part: genus

• Second part: species

• Ex: Puma concolor

• Common name: mountain lion, cougar, puma

• Scientific name: Puma Concolor

Linnaeus’ Classification System Has 7 Levels

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

Linnaean Classification System

If two species belong to the same order, what other levels in the

Linnaean system must they have in common?

• Kingdom• Phylum• Class• Order• Family• Genus• Species

If two species belong to the same order, what other levels in the

Linnaean system must they have in common?

• Kingdom• Phylum• Class• Order• Family• Genus• Species

• ANSWER: Kingdom, Phylum, Class

What limitations may the Linnaean system have?

• This system focuses on physical similarities alone

• Before technology allowed us to study organisms at the molecular level.

• Does not account for similarities that evolved through convergent evolution.

EX: the Red Panda which is more closely related to raccoons than Giant Panda’s.

Cladistics

• Classification based on common ancestry

• Uses evidence from living species, the fossil record, and molecular data

• Phylogeny: evolutionary history for a group of species.

Cladogram

• An evolutionary tree that proposes how species may be related to each other through common ancestors.

Animal Diversity

• Each animal Phylum has a unique body plan

• Animals are grouped using a variety of criteria

• A comparison of structure and genetics reveals the evolutionary history of animals.

Vertebrates

• An animal with an internal segmented backbone

• Most obvious animals around us

• Make up less than 5% of all known animal species

Invertebrates

• Animals without a backbone

• Most are not closely related to each other

Phylum Chordata

• Contains all vertebrates and some invertebrates

• Vertebrates: large, active animals that have a well-developed brain encased in a hard skull.

• Tunicates: urochordates, including both free-swimming and sessile animals such as sea squirts.

• Lancelets: cephalochordates, small eel-like animals that are commonly found in shallow tropical oceans.

Tunicates

Lancelets

Chordates share 4 common features- at some stage of development

1. Notochord: flexible skeletal support rod embedded in the animal’s back.

2. Hollow nerve chord: runs along the animal’s back

3. Pharyngeal slits: through the body wall in the pharynx. Water can enter the mouth and leave without passing through the entire digestive system.

4. Tail: contains segments of muscle tissue used for movement.

Endoskeleton

• An internal skeleton built of bone or cartilage

Vertebrate Classes

• Agnatha

• Chondrichthyes

• Osteichthyes

• Amphibia

• Reptilia

• Aves

• Mammalia

Class Agnatha

• Oldest class of vertebrates

• Jawless animals• Include lampreys, a

type of fish

Class Chondrichthyes

• Cartilaginous fish

• Animals include sharks, rays and chimeras

Class Osteichthyes

• Bony Fish• Have skeletons made

of bone

Class Amphibia

• First vertebrates adapted to live both in water and on land

• Include salamanders, frogs, toads, and caecilians

Class Reptilia

• Able to retain moisture, lets them live exclusively on land.

• Produce eggs• Include snakes,

lizards, crocodiles, alligators, and turtles

Class Aves

• Birds• Presence of feathers

Class Mammalia

• Animals that have hair, mammary glands, and three middle ear bones.