Unit 9--Vertebrates

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Unit 9--Vertebrates

• Chapter 30-32
• Nonvertebrate Chordates, Fishes Amphibians
• Reptiles Birds
• Mammals

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Phylum Chordata Characteristics

• At some time in their life, all chordates have
• A dorsal nerve cord gives rise to spinal cord
• A notochord flexible supporting rod that gives
  rise to vertebrae
• Postanal Tail that extends beyond the anus
• Pharyngeal slits gives rise to gills
• Most in subphylum Vertebrata

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Dorsal, hollow nerve cord

• Located on the back (dorsal) part of the body
• Nerves branch from this to all parts of the
  animals body

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Notochord
Embryonic Ciona with visible notochord Doe Joint
Genome Institute

• Located beneath the nerve cord
• Long supporting rod
• For most vertebrates, the notochord is present
  only in the embryo stage.
• In some, vertebrae (backbone) replaces the
  notochord.

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Notochord formation
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Pharyngeal pouches

• Paired structures in the throat (pharynx) region
• For fishes, slits develop that connect the
  pouches to the outside of the body, becoming
  gills.

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Postanal tail

• Extends beyond the anus
• Bone and muscle within
• Facilitates in swimming

human embryo with tailbud
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Chordate Cladogram
Section 30-1
Mammals
Birds
Reptiles
Amphibians
Fishes
Nonvertebratechordates
Invertebrate ancestor
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Subphylum
Urochordata Tunicate (sea squirt) only larva
has all characteristics
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Subphylum
Cephalochordata Lancelets the only
adult to retain all characteristics
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Lancelet characteristics

• Small, fishlike animals
• Live on ocean floor
• An adult lancelet has a mouth that connects to
  the pharynx, which secretes a sticky mucus to
  trap
• food.
• Closed circulatory system but no true heart

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Subphylum Vertebrata

• Class Agnatha the jawless fishes
• Ex sea lampreys hagfish

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Lamprey are external parasites,
1 while hagfish are bottom feeders.
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Class Chondrichthyes

• Cartilaginous fishes
• Ex Sharks, rays skates

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Sharks have several 6-10 rows of replaceable
teeth and toothlike placoid scales
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Shark bite
Note the size of the shark tooth as compared the
size of an average adult hand.
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Class Osteichthyes

• Bony fish (with jaws paired fins)
• Ex sea horse, lion fish, perch, trout, etc

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Fish anatomy

• Overlapping scales for protection
• Gills with countercurrent exchange
• Operculum gill cover
• Flattened bodies to increase speed

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Respiration

• Most fishes use gills.
• Gills are made up of feathery, threadlike
  structures called filaments.
• The operculum, a bony covering, protects the gill
  slit(s).

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Feeding

• Types of feeders
• Herbivores vegetative matter only
• Carnivores meat only
• Parasites feeds on other animals
• Filter feeders sifts matter out of water
• Detritus feeders feeds on dead or decaying
  matter
• Food enters the mouth, stomach, pyloric ceca
  (digestive enzymes), intestines, and out the anus.

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Movement

• Alternating muscles on either side of the spine
  allows for S-shaped curve that pushes water
• Fins for directional movement
• Swim bladder helps to adjust for buoyancy

swim bladder
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Response

• Well-developed brain and chemoreceptors to detect
  taste and smells
• Lateral line system that detect vibration and
  current changes

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Class Amphibia

• double life
• Ex frogs toads, salamanders, newts

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Amphibian characteristics

• Vertebrate
• Lives in water as a larva but on land as an adult
• May returns to water to reproduce
• Uses gills as larva but lungs as an adult
• Moist skin with mucus glands
• No scales or claws

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Amphibian Anatomy

• Inefficient 3 chambered heart
• Skin breathing to help inefficient lungs
• Moist skin
• Webbed feet, no claws
• Metamorphosis

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Reptilian characteristics

• Dry, scaly skin
• Lungs
• Internal fertilization
• Terrestrial eggs with several membranes
• Double-loop circulatory system
• Strong limbs
• Ectothermic
• Vertebrate
• Diverse habitats

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Reptile anatomy

• Ectothermic (cold-blooded) body temp changes
  with environment
• Dry, waterproof skin with claws
• Partially divided 3 chambered heart

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Class Reptilia

• Ex snakes, lizards, turtles, alligators
• Tuatara only member is its order

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Amniote Egg allows reptiles to lay eggs on land
CHORION
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Rattlesnakes are Pit vipers with a heat
sensitive organ that detects warm-blooded prey
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Class Aves (the birds)

• Endothermic (warm-blooded) body temp constant
• 4 chambered heart
• Well-developed lungs

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Bird characteristics

• Reptile-like
• Aerodynamic feathers
• Two legs covered with scales
• Front limbs modified into wings
• Highly efficient metabolism
• Strong, lightweight bones

Levy
Volta the bald eagle Alaskan Bird
Rehabilitation Center
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Reptiles vs. Birds

• Feathers are produced by tissues similar to those
  that produce reptile scales.
• Birds have scales on their feet.
• Birds lay eggs like reptiles.
• The soft anatomy (musculature, brain, heart, and
  other organs) all are fairly similar.

Information from UC Berkeley, Museum of
Paleontology
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Bird Anatomy

• Feathers for insulation, protection coloration,
  assist in flight
• Hollow bones for lightweight

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Birds reduce weight for flight whenever possible,
i.e. air sacs attached to lungs one ovary in
females.
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Compare Heart chambers Skin coverings
Respiration types Cold vs Warm-blooded
Reproduction types
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Mammal characteristics

• Hair
• Mammary glands
• Require oxygen
• Four chambered hearts
• Endothermic

Sea World, whale calf nursing
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Class Mammalia

• Hair (to insulate, camouflage, etc)
• Mammary glands (to nurse young)
• Viviparous (bear live young)
• Specialized teeth (determines lifestyle)
• Nails, claws or hooves

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Regulating Body Temperature

• Endotherm animal that can generate body heat
  internally through metabolic processes
• Body hair insulates
• Subcutaneous fat layer beneath the skin to help
  conserve heat
• Sweat glands evaporative cooling
• Regulating body temperature homeostasis

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Hair

• Only mammals have hair. Whales and dolphins
  (marine mammals) have sensitive bristles on their
  snouts.
• Functions insulation, camouflage, sensory input
  (environmental awareness)

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Feeding

• Because of metabolic rate, mammals must eat 10x
  the amount of food as reptiles.
• Herbivores consume only vegetative matter
• Carnivores consume only meat
• Omnivores consume meat and vegetables
• Filter feeders sift out plankton and small fish
  from water
• Name an example of each type of animal feeder.

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Specialized teeth
Section 32-1
CARNIVORE
HERBIVORE
Jawjoint
Jaw joint
Horse
Wolf
Figure 324 The Jaws and Teeth of Mammals (p. 823)
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Respiration

• All mammals, even marine, have lungs to breathe
  in oxygen and exhale carbon dioxide.
• The diaphragm muscle lowers to help expand the
  chest cavity for greater volume.

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Excretion

• Kidneys help mammals maintain homeostasis (water
  and salt balance).

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Response

• Mammals have the most highly developed brains.
• Diurnal animals have the best developed color
  vision since these animals are awake during
  daylight.
• Mammals also have highly developed sense of smell
  and hearing.

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Chemical Controls

• Endocrine glands produce and secrete hormones
  that affect other organs and tissues
• Hormones can regulate mammal behavior and vital
  functions such as maintaining blood sugar or
  calcium levels.

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Fighting Disease

• Immune systems help mammals ward off pathogens,
  disease-causing microorganisms, that may invade
  the body.

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Reproduction

• All mammals
• Internal fertilization male deposits sperm
  inside the female reproductive tract
• requires mothers milk for nourishment when young
• display maternal care

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Classification by reproduction

• Monotremes (egg-laying)
• Ex platypus echidna
• Marsupials (pouched)
• Ex koala, kangaroo
  opossum

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Reproduction

• Different ways that fetal mammals develop
• Monotremes lay eggs
• Platypus, spiny anteaters (echidnas)
• Marsupials live birth of young that then finish
  development in an external pouch
• Kangaroo, koala, wombat
• Placental nutrients, oxygen, carbon dioxide, and
  wastes are exchanged between embryo and mother
  through the placenta structure
• Primates, dogs, cats, pigs, horses, etc.

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Placental Mammals
Include 95 of all Mammals
Includes 15 orders
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Rodentia (gnawing)
largest, most successful order
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Insectivores moles
include smallest mammal, the shrew
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Edentates (toothless)
most primitive
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Chiroptera bats
Bats are only mammals capable of true flight
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Carnivora
special traits for hunting
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Cetaceans whales, dolphins
Aquatic mammals are capable of holding their
breath for several hours
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___dactyla
Hoofed mammals Are grouped by Number of
toes (even or odd) They tend to be Large
grazers
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Probosiceans elephants
Trunk-nosed mammals have only 2 species, African
and Indian
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Primates
have opposable thumbs superior intelligence
They are the only mammal to make use of tools