Kindom Animalia, Phylum Chordata pgs 448- 479

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Kindom Animalia, Phylum Chordata pgs 448- 479

• Biology 11

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What characteristics set chordates apart from
other phyla?

• At some point in their development all chordates
  have these 4 structural characteristics
• A notochord becomes the vertebral column in
  humans
• A muscular pharynx with gill slits
• A post-anal tail the coccyx in humans
• A hollow dorsal nerve chord later modified into
  a brain and spinal cord
• These attributes are always found in the larval
  forms or early embryo, although they may be
  absent in the adult.

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Phylum Chordata is divided into three subphyla

• Subphylum Urochordata
• Example tinucates
• Subphylum Cephalochordata
• Example Lancelets
• Subphylum Vertebrata
• Examples fish, amphibians, reptiles, birds,
  mammals

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Subphylum Urochordata Subphylum Cephalochordata

• Represent 5 of chordates
• Aquatic animals that possess the 4
  characteristics of chordates.
• No backbone or vertebral column
• Perhaps represent a transient step between
  invertebrates and vertebrates

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Subphyum Vertebrata

• 95 of all chordates
• All possess vertebrae, which are hollow
  cartilaginous or bony structures that surround
  the dorsal nerve cord.
• Body plan includes (pg 449)
• Endoskeleton
• Large brain with a protective skull
• Advanced nervous system
• Complex heart and circulatory system
• Special outer body cover
• One to two pairs of appendages
• Large coelom

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Subphylum Vetebrata Terminology

• Endotherm warm blooded animals. Internal
  temperature remains constant regardless of
  environment. Ex mammals and birds.
• Ectotherms cold blooded animals. Body
  temperature and metabolic rate change with the
  surroundings. Ex all other vertebrates including
  fish, frogs, snakes etc.

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12.2 Fish pg 452

• Divided into 3 groups
• Jawless Class Agnatha. Ex lampreys, hagfish
• Cartilaginous Class Chondrictheys. Ex Sharks,
  skates, rays
• Bony fish - Class Osteichthyes. Ex Salmon,
  trout, tuna.

Organ/Structure Function
Heart 2 chambered heart.
Circulatory System Blood vessels circulate oxygenated blood
Respiration Blood travel to Gills to be oxygenated
Nervous System Brain, spinal cord and peripheral nervous system.
Reproduction Separate sexes. Internal and external fertilization.
Digestion One way, developed system.
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Fish Circulatory System
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Lobe-finned fish? Amphibians

• Lobe-finned fish, have a fleshy lobe at the base
  of their fins that is leg-like in appearance.
  Scientists believe that this fish is the ancestor
  of amphibians! Amphibians first appeared 350
  million years ago.
• Figure 6, pg 454
• Lobe-finned fish, were thought to be extinct
  until 1938, when a coelacanth Latimeria was first
  captured by chance, they were known only from the
  fossil record. Since then several dozen have been
  captured and some of their behavior has been
  filmed using robotic cameras.
• Latimeria is important because it provides an
  opportunity to compare observations from the
  fossil record with a living animal.

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12.3 Amphibians pg 455

• Reproduction
• external fertilization which only
• occurs in aquatic environments.
• Gas exchange
• Young amphibians use gills as they live in
  aquatic environments.
• Adult amphibians perform gas exchange through
  moist skin, (cutaneous respiration), and poorly
  developed lungs with little internal folding and
  a small surface area as they are mostly
  terrestrial.
• Nervous and Digestion Systems highly developed
  nervous and digestive systems.

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12.3 Amphibians pg 455

• Circulatory System
• Inefficient 3 chambered heart where oxygenated
  blood and deoxygenated blood are mixed and then
  pumped to the body.

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12.4 Reptiles pg 457

• Reptiles are the first fully terrestrial animals.
• Reptiles first appeared 350 million years ago.
• 3 subclasses
• Anapsida turtles, tortoises
• Lepidosaura lizards, snakes, tuatara
• Archosaura crocodiles, aligators and dinosaurs
• Body plan includes
• Thick skin with protective with surface scales to
  prevent water loss (gas exchange)
• Highly developed lungs with much internal folding
• More developed 3 chambered heart
• The amniotic egg
• Lightweight skeleton
• Different joint positions allowing for more
  efficient movement

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12.4 Reptiles pg 457
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12.5 Birds pg 461Class Aves

• Characteristics of birds
• Descendant of reptiles, similarities retained
  include skull structure, and presence of scales
  on beak, legs and feet.
• The first endotherms
• Only animal with feathers (evolved from reptilian
  scales)
• Their anterior limbs are modified as wings for
  flight, while the posterior pair is adapted for
  walking, swimming, or perching.

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12.5 Birds pg 461Class Aves

• Characteristics for Flight
• Circulatory System 4 chambered heart. No mixing
  of oxygenated and deoxygenated blood.
• Respiratory System Highly developed lungs and
  the presence of air sacs which provide continuous
  oxygen as well as buoyancy.
• Limbs lighter, hollow bones.
• Excretion purely semi solid, no urinary bladder
• Digestion rapid and efficient
• Senses excellent hearing and acute colour
  vision. Superior sight during the day and night.

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12.6 Mammals pg 465

• Monotremes mammals that reproduce by laying
  eggs. Descendant of a different reptilian
  ancestor than other mammals.
• Example duck billed platypus.
• Marsupials mammals that give birth to partially
  developed embryo that continue further
  development in the mothers pouch.
• Example kangaroos, wallabies, and koalas
• Placental Mammals a type of mammal that has all
  of the embryo development within the uterus of
  the female. Includes 95 of all mammals.
• Example humans, dogs, horses etc

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12.6 Mammals pg 465

• Mammalian Characteristics include
• Hair
• Sweat glands
• Teeth
• Fleshy lips
• A diaphragm
• A four chambered heart
• A middle ear
• Mammary glands that produce milk (females)
• Endoskeleton
• A complex brain and nervous system

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4 chambered heart
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Application Questions

• Phylum Chordata
• Read pgs 446-450, do questions pg 449, questions
  1, 4, pg 452 3, 4
• Class Fish
• Read pgs 452-455, do questions pg 454, questions
  1, 5, pg 455 4,
• Class Amphibian
• Read pgs 455-457, do questions pg 460, questions
  1, 2

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Application Questions

• Class Reptilia
• Read pgs 457-461, do questions pg 460, questions
  3, pg 461 2,4,5
• Class Aves
• Read pgs 461-465, do questions pg 465, questions
  1, 2
• Class Mammalia
• Read pgs 465-478, do questions pg 478, questions
  6, pg 481 5, 7, 9