It All Begins 530 Million Years Ago…. with Jawless Fish Swims Side to Side Motion Tiny Armor plates cover body Wide set eyes Has a BACKBONE!

Kingdom Animalia Phylum: Chordata

Phylum: Chordata – members called chordates All have slits in throat area at some point. All have a backbone OR a notochord to support body (A notochord is a flexible rod) All have a nerve cord running down the back What is this nerve cord in humans? SPINAL CORD MOST are vertebrates The ancient jawless fish is part of a phylum called Chordata. All members in chordata are called Chordates.

Notochord- found in embryo stage of all chordates & some adults https://www.youtube.com/watch?v=nNPY9evldis

Gill Slits in all Chordates

MAJOR GROUPS OF CHORDATA FISHES AMPHIBIANS REPTILES BIRDS MAMMALS

Most Chordates are Vertebrates VERTEBRATES ARE A SUBPHYLUM OF CHORDATES A Vertebrate has a BACKBONE that is part of an internal skeleton Another name for backbone is SPINE Internal skeleton is called an ENDOSKELETON Other Animals, like insects have EXOSKELETON

Most Chordates are Vertebrates Backbone is made of many VERTEBRAE or bones lined up in a row with flexible joints Each vertebra has a HOLE that allows SPINAL CORD/NERVE CORD to pass through

INTERNAL SKELETON:ENDOSKELETON Backbone is only part of endoskeleton Also includes: SKULL & RIBS, ARM & LEG BONES (if present)

FUNCTIONS OF ENDOSKELETON Protect internal organs Give body shape & support Give muscles a place to attach

OTHER CHARACTERISTICS: Endoskeleton grows with the animal – doesn’t have to be replaced like an exoskeleton ADVANTAGE! Animal can grow BIGGER than animals with either an exoskeleton or no skeleton

CONTROLLING BODY TEMPERATURE: There are 2 types of Vertebrates in relation to controlling body temperature: 1. Ectotherms 2. Endotherms

An animal whose body DOES NOT produce much INTERNAL heat ECTOTHERMS: An animal whose body DOES NOT produce much INTERNAL heat Body temperature changes with the temperature of their environment Sometimes called COLDBLOODED Misnomer – sometimes blood is quite warm! Includes: fish, amphibians & reptiles

Ectotherms

Includes: Birds & Mammals ENDOTHERMS An animal whose body regulates its own body temperature no matter what the temperature of the environment. ADAPTATIONS: Sweat glands Fur Hair Feathers Includes: Birds & Mammals

Advantage: https://www.youtube.com/watch?v=LH1p1XOqfsg Endotherms can live in a greater variety of environments than ectotherms Why? Because they can take steps to keep their body temperature stable. Ectotherms are dependent on environment. ASSIGNMENT: Read Summary & Complete Review & Reinforce. https://www.youtube.com/watch?v=LH1p1XOqfsg