Bio Chapt 24

vertebrates

• ^{1. dorsal hollow nerve cord..(forms brain)}
• 2. post anal tail
• 3. notochord (stiff flexible rod extending the length of body
• 4. pharyngeal gill slits ( located in pharynx may form resiratory organs)

Yes, but only retained characterist we have past the embryonic stage of life is the Dorsal Nerve Cord

Invertebrates!

• 1. Celphalchordates: Lancelets
• 2. Urochordates: Sea squirt, tunactes

• retain all 4 chordate features as adults
• They live nearly barried in sand
• Have cilia which draws food into mouth

• Sea squirts:
• exhibit all key chordate features
• filter feeders as adult and lost tail and notochord
• have encircling band of muscles which propels them forward

include all chordates that have a skull and encloses a brain...Hagfish

First ones to start having a backbone..Vertebral colum composed of bone or cartilage (more flexible than bone)

only having notocord as larva and not having jaws but having actual backbone

• 1. hagfish
• 2. lamprey

include Sharks, skates, rays

they have cartilaginous skeleton, and leathery skin with tiny scales

two chambered hearts, internal fertilization, Sinks when not swimming b/c lack a swim bladder

something that helps fish stablize in water so they do not sink

most fish in the ocean from sea horse to angler fish

• 1. ray finned: angler fish, moray eel, seahorse
• 2. lobe finned fish: lung fish and coelacanth

structure of fins (webed with body spines), boney skeleton, interlocking scales, 2 chamber hearts, gills for respiration, swim bladder, human food source greatly impacts their population

• ones that live in mud: lungfish. Live in freshwater habitats, low oxygen, gills and lungs..
• also they evolved to reptiles amphibians and mamals today,

frogs toads, salamanders, caecilians

Need aquatic enviorment expecially when young. Lungs do not fully develope until adults. 3 chambered heart, moist skin, 4 limbs!!!!, sexually reproduce using external fertilization

limbless, and look like very large earthworm

Lizards, snakes, alligator, crocodiles, turtles, birds

lungs, Adapted to life on land..a step up from amphibians. tougher scally skin protects against loss of water. internal fertilization..Amniotic egg..amnion (fluid filled membrane prevents drying out. 3/4 chamberd hearts more efficant then amphibian chambed heart by seperating oxygen/deoxygenated, do not breath through skin, Skeleton: better movement

special sensing organs track prey w temp. can have Venom, jaw joints!!

move babies from eggs to water in mouth

leatherback eats jellyfish

• appear in fossil record 150 million years ago..
• Feathers!! scales on legs. Earliest know bird Archaeopteryx

• 1. feathers
• 2. hollow bones
• 3. reproductive organs shrink when not matting periods
• female, single ovary
• 4. nervous system provides extraordinary coordination and balance for flight, acute eyesight

• and 4 chambered heart
• Air sacs that provide a continuous supply of oxygenated air to the lungs, and even when bird exhales

250 million years ago: Mammary glands, warmblooded, 4 chambered heart, hair that protects and insulates, legs desighned for running rather than crawling, sweat scent, sebaceous (oil producing glands)...not found in other vertebrates

• 1. Monotremes: egg laying (leathery eggs) mammals, Platypus, echidnas.
• 2: marsupials:SACS
• 3. Placental mammals: highly diverse!! rodents 40% of mammal species. 20% are bats