bio 2 - animals ch 32 (post)

chodate

phylum Chordata - characteristics at some time in the life cycle:

• notochord

• nerve cord

• pharyngeal pouches

• postanal tail

postanal tail - chordates

extends beyond the anus

pharyngeal pouches

final development depends on the adult chordate

•Most vertebrates have this only in embryonic development

• in some non vert chordates this becomes functioning gills

notochord

dorsal supporting rod, replaced by vertebral column during development in vertebrates

Dorsal tubular nerve cord—nerve cord containing a fluid-filled canal

nonvertebrate chordates

•Tunicates and lancelets

•Do not have vertebrae

incomplete digestive tract means

only one digestive hole

vertebrate chordates

Fishes, amphibians, reptiles, birds, mammals

• Cartilaginous fish: first to develop jaws

• Some early bony fish had lungs

• Amphibians were the first to have jointed appendages

• Reptiles and mammals had terrestrial adaptations for reproduction

  • Amnion and extraembryonic membranes support the embryo and prevent it from drying as it develops

lobe finned fish

fishes from the Devonian era had fleshy appendages with bones homologous to those of terrestrial vertebrates

•These are believed to be ancestral to amphibians

lancelet - nonvertebrate chordates

class Leptocardii

• notochord never becomes a vertebral column

• Knife-shaped bodies a few centimeters long

• Live in shallow coastal waters

• Retain all four chordate characteristics as an adult

• Segmentation - muscles and branched nerve cord

tunicates - nonvertebrate chordates

subphylum Tunicata

• live in ocean and filter feeders

• larva has bilateral symmetry and all four chordate characteristics

• Adults are sessile, thick-walled, saclike organisms with incurrent and excurrent siphons

  • Tunicates (sea squirts) squirt water when their siphons are disturbed

  • The only chordate characteristic remaining in the adults is the pharynx with gill slits

• pharynx lined by cilia which move the water and eat the particles that get adhered to the muscus

vertebrate features

have all four chordate characteristics at some time in their life history

•The embryonic notochord is replaced by a vertebral column with individual vertebrae

•Vertebral column provides evidence of vertebrate segmentation and is part of a strong, jointed endoskeleton

•The skeleton protects internal organs and is a place of muscle attachment

•Together, the skeletal and muscular systems permit rapid and efficient movement

•Two pairs of appendages typical

•Skull encloses and protects brain

•High degree of cephalization and complex sense organs (eyes, ears)

•Evolution of jaws provided variety of biological roles

•Complete digestive tract and large coelom

•Closed circulatory system

•Efficient respiration from water or air

Kidneys used for excretion and water regulation

the pectoral and pelvic fins of fish evolved into:

jointed appendages that allowed verebrates to move on land

vertebrate sex features for fishes and amphibians

Separate sexes and usually sexual reproduction

Reproduction on land possible due to evolution of the amnion

•Many reptile species and a few mammals lay shelled amniotic eggs

•In placental mammals, development occurs in the uterus

milestones in veretbrate evolution

• jaw allowed for predation

• limbs allowed for locomotion

• Amnion and shelled egg allowed for reproduction on land

fish - evolution of the jaw

• cartilaginous and body fish now have them

• they are tooth bearing structures in the head that evolved from gill arches and allow predatory way of life

jawless fish

• Agnathans

• clindrical with smooth, scaleless skin, no jaws, no paired fins

• two groups: hagfishes and lampreys

hagfish - jawless fish (agnathans)

class Myxini - are scavengers

Have a skull but lack vertebrae (may have been lost)

lamprey - jawless fish (agnathans)

class cephaaspinidomorphi

• parasitic

• have a true vertebral column

• sucker mouth - attach to other fish

• Water moves in and out of gills directly; not through mouth as in other fish

cartilaginous fish

• •Sharks, skates, rays, and chimaeras

• no bone

• 5-7 gill slits

• no gill cover

• have gill chambers (called spiracles) behind their eyes

• Body covered with dermal denticles—tiny, teethlike scales that project posteriorly

  • gives sharks skin the sandpaper feel

  • shark teeth are large and specialiazed versions of scales

• lateral line system - used to sense pressure caused by movement to detect prey

bony fish

includes: ray-finned fish and lobe finned fish

• paired fins supported by thin, bony rays

• swim bladder for buoyance

• streamlined shape

• Skin covered with bony scales for protection

• Water pumped across gills → enters mouth exists gill slits (where gas exchange is)

• blood is pumped by two chamber heart through single circuit circulatory system

lobe finned fish - bony fish

• Ancestors of the amphibians

• fleshy appendages that could be adapted for movement on land

• most have lungs

• The coelacanth is one type thought to have gone extinct but that has been discovered again

vertebrate circulatory pathway of fish

vertebrate circulatory pathway of amphibians and most reptiles

vertebrate circulatory pathway of some reptiles, birds, and mammals

amphibians

• means living on land and water

• includes salamanders, frogs, toads, and newts

• Caecilians are fossorial, wormlike amphibians that are limbless and spend most of the time underground

amphibians characteristics

• jointed appendages (other than in caecilians)

• four limbs

• eyelids

• ears (tympanum) to pick up sound

• larynx for vocalization

amphibians transition to land

• larger brain than in fish relative to body size

• small lungs - air goes through nose and to floor of mouth

• three chambered heart

• larval stages in water and adults on land. reproduce generally in water

vertebrates: reptiles

• most abundant 245-65 MYA

• include dinosaurs, ancestors of the mammals, and modern-day birds

• turtles, alligators, snakes, lizards, and birds

• ectothermic so they try regulate body temp by exposure to the sun

reptiles - amniotic egg reproduction on land

• male penis passes sperm directly into female

• fertilization is internal

• amniotic egg made development on land possible and eliminated the need for a swimming larval stage

ectothermic

animals where their body temperature is the same as that of the external environment

• fish, amphibians, living reptiles (Excluding birds)

birds - featured reptiles

• class Aves

• Feathers are modified scales; legs of birds have scales

• Amniotic egg with a hard shell instead of leathery eggs of reptiles

anatomy and physiology of birds

• features related to ability to fly

  • forelimb modified to be a wing

  • light and hoow bones

  • beak instead of jaw

  • sternum made for flight muscle attachment

  • lobular lungs with air sacs increase efficiency of gas exchange and lighten body for flight

heart/circulatory system for birds

• four chambered hears that separate o2 rich and poor blood

• endothermic

• feathers help maintain body temp

• no bladder and excrete uric acid in semidry state

diversity of birds

• some are flighless

• classified by beak, foot type, habitat, and behavior

mammals

• evolved from reptiles

• chief characteristics: body hair and milk-producing mammary glands

• endothermic - hair provides insulation

• efficient respiratory and circulatory systems similar to birds

• double loop circulation and four chambered heart

mammal classification

monotremes, marsupials, or placental mammals

monotremes - types of mammals

• have a cloaca- terminal region of digestive tract that serves as a common chamber for feces, excretory wastes, and sex cells

• lay hard shelled amniotic eggs

• Secrete milk onto body surface (both males and females) of abdomen

  • young drink the milk

• anteaters and platypus of Australia and New Guinea

marsupials

• begin dev in female body and born immature but complete dev in pouch near abdomen w nipples of mammary glands in pouch

• kangaroo, koalas, and opossums

placental mammals

majority of this species

• classified by methods of obtaining food and mode of locomotions

• Extraembryonic membranes of the reptilian egg are modified for internal development

• dev occurs in uterus with chorion contributing to fetal part of placenta and portion of the uterine wall contribute to maternal part and maerials exchanged between fetus and moms blood at placenta

placenta mammals - adaptations to active life on land

• limbs allove for movement

• lungs expanded by rig cage and contraction of the diaphragm

• four chambered heart

• constant internal body temp

• body insulating hair

• well developed brain, enlarged due to expansion of cerebral hemispheres

placental mammals - differentiated teeth

• Incisors and canines at the front of the mouth have cutting edges for capturing and killing prey

• Premolars and molars chew food on the sides of the mouth

• shape and size associated with if they are herbivores, carnivores, or omnivores

order rodentia

placental mammals with ever growing incisors

order carinvora

placental mammals with long canine teeth

order chiroptera

placental mammals with wings supporteed by digits for flights - bats

order perissodactyla

placental mammals with long hoofed legs for speed - horses

order cetacae

placental mammals like whales with paddlelike forelimbs

benefits of primate arboreal adaptations

• powerful and precise grip

• easier to reach food and bring to mouth

• improve grasping and releasing tree limbs in locomotion

primate characteristics

• mobile limbs

• hands and feet have five digits

• many have opposable thumbs and big toes (humans only have opposable thumbs)

• shortened snout for eyes to be in front of head during evolution

• can see colors

• cephalization

primate birth

• one offspring per birth interval is the norm

  • More difficult to care for offspring while moving from limb to limb

  • leads to extended period of juvanile dependency