Packet #78Chapter #34

IntroductionAll vertebrates are

Found within Phylum Chordata; Subphylum Vertebrata

DeuterostomesCoelomatesBilateral symmetricalHave an endoskeletonHave a closed circulatory systemHave a ventral heart

Introduction IIDuring the lifespan of chordates, they have a

notochord which serves as a flexible supporting rod.

Chordates have a single dorsal tubular(hollow) nerve cord.

All chordates have pharyngeal gill siltsIn some species, the gill slits are only found in

the embryosMOST chordates have a muscular postanal

tail.

Invertebrates vs. VertebratesHow are the two invertebrate subphyla of

chordates related to the vertebrate chordates?• Animals in the Subphylum Vertebrata retain the

characteristics of the other chordates.• However, many of the additional features that

separate the vertebrates from the other chordates are associated with a larger size and a mobile lifestyle.

• A major additional feature is the head Chordates with a head are known as craniates

Phylum ChordataPreviously covered from Phylum Chordata

were the two subphyla of invertebratesTunicatesLancelets

This packet will investigate SOME of the remaining organisms of this vast and wide phylum.

Phylum ChordataSubphylym VertebrataClass AgnathaInclude the lampreys

and hagfishes.Both are scales,

elongate fish without jaws or paired fins

Hagfish are marine scavengers

Lampreys are found in freshwater or marine habitats and include ectoparasitic species.

Class ChondrichthyesIncludes sharks, rays

and skatesCartilaginous fish have 5

– 7 pairs of gills and rely on swimming to force water

Sharks, and their relatives, have paired fins and placoid scales.Sharks may be

oviparous, ovoviviparous or viviparous.

Class OsteichthyesThis class is the most

speciose of the vertebrate classes.

Skeleton is composed of bone and is covered with overlapping flexible scales

Oviparous and produce a prodicious number of eggs.

Class Amphibia Include frogs, toads and

salamanders. Some members lack tails

Toads & frogs Some members lack legs

Tropical caecilians The larvae of toads and frogs are

aquatic Some salamanders undergo

neoteny. Retention of juvenile

characteristics in the adults of a species, as among certain amphibians. Reflect back to past genetics packet.

Adult amphibians rely heavily on cutaneous respiration

The amphibian hear has three chambers (a atria and 1 ventricle) that allows a partially separated pulmonary and systemic circulation

Class Reptilia Includes turtles, lizards, snakes and

alligators Terrestrial animals that do not rely on

reproduce Dinosaurs are thought to be reptiles.

Became extinct at some point in earth’s history

Bodies covered in dry scales to prevent cutansous respiration

Lungs are more efficient than amphibians.

Waste is excreted in the form of uric acid

Reduces water loss Ectothermic organisms—similar to fish

and amphibians Most are carnivores Snakes have unusual adaptations for

efficient predation Chemical and temperature senses Produce toxins

Class Aves [ey-veez]The anterior appendages of

birds are winds and MOST birds do fly.

In order to fly, birds have skeletal reduction, efficient lungs, a four chambered heart, endothermy and frequent voiding of wastes.

Birds eat high energy foods to maintain a high metabolic rate.

The nervous system is cell developed Sight and hearing

Display complex social behaviors, vocalizations and territorial behaviors.

MammalsMammals are characterized by hair and mammary

glands.Mammals have specializations in dentition, a

diaphragm to aid in respiration, endothermy and a four chambered heart.

The nervous system, particularly the cerebrum, is quite advanced.

Fertilization is always internal and nearly all mammals are viviparous

Most mammals are placentalThe limbs are adapted for diverse forms of locomotion

MonotremesSubclass PrototheriaMammals that lay

eggsInclude the duck-

billed platypus and spiny anteater (echidna).

When the young hatch, they feed on the milk produced by the mammary glands.

MarsupialsSubclass MetatheriaPouched animalsInclude kangaroos,

koalas and opossumsMost common in

Australia

Placental MammalsSubclass EutheriaMammals that

complete embryonic development within the mother.

The most common form of mammals.

There is a placental connection between the embryo and the mother in the uterus.

Review I

Review II

Review III