Unit 9: Chordates

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Unit 9 Chordates

• Chapter 30 - 34
• Biology

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30-1 The Chordates
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What is a Chordate?

• An animal that has
• Dorsal hollow nerve cord
• Notochord long supporting rod that runs through
  the body just below the nerve cord
• Pharyngeal pouches
• Tail that extends beyond the anus

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Most Chordates are Vertebrates

• Vertebrae the individual segments of the
  backbone, which replaces the notochord in most
  developing vertebrates

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Characteristics of Invertebrate Chordates

• Phylum Chordata
• Subphylum Urochordata and Cephalochordata
• Dorsal hollow nerve chord
• Notochord, muscle blocks, gill slits, and a tail
  at some stage during development
• include Sea squirts and Lancelets

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30-2 Fishes
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What is a Fish?

• Aquatic vertebrates
• Most have paired fins and gills
• Bilaterally symmetrical
• Have scales
• Cartilaginous and bony fish
• Coelomate w/ endoskeleton
• Most have external fertilization
• Sexual w/ different sexes

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• Closed circulatory system
• 2 chambered heart
• Nervous system
• complex brain sense organs
• Efficient respiratory system
• Breath w/ gills
• 3 classes of fish

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Class Agnatha

• Jawless fish
• Lampreys and hagfish
• Feeding
• Parasitic (lampreys)- use sucker-like mouths to
  attach to prey and scrap prey and suck out the
  blood
• Feed by drilling a hole (slit-like toothed mouth)
  into dead or dying fish and sucking their blood
  (hagfish)

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Class Agnatha

• Locomotion
• Move in a snake-like pattern
• No fins
• Have no scales

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Class Chondrichthyes

• Cartilaginous fish
• Sharks, skates and rays
• Feeding
• Predators
• Typically feed on or near the ocean floor
• Skeleton composed completely of cartilage
• Paired fins that aid in locomotion
• Lateral line system used to sense their
  environment
• Have a jaw

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Class Chondrichthyes

• Rays (characteristics)
• Flat bodies w/ broad pectoral fins on side
• Move by flapping fins up and down
• Eat mollusk and crustaceans
• Adaptations
• Sharp spines w/ poison glands located on the tail
• Some can produce electricity

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Class Osteichthyes

• Bony fish
• All other fish
  (i.e. bass, crappie, catfish, etc.)
• Have backbone composed of separate hard segments
  called vertebra
• Provides support and flexibility
• Paired fins - locomotion
• Lateral line system
• Have scales
• Swim bladder - functions in buoyancy

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30-3 Amphibians
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Characteristics of Amphibians

• Class Amphibia
• Means double-life
• completely aquatic larvae
• Air breathing semi terrestrial
• External fertilization
• Eggs lack protective membrane and shells
• Adults have 3 chambered heart
• Exchange gasses through skin
• Undergo metamorphosis

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Characteristics of Amphibians

• Ectotherms (cold blooded)
• Temperature changes with environment
• 3 orders
• Urodela (salamanders and newts)
• Long slender body w/ neck and tail
• Smooth moist skin that lack claws
• Live entirely in water
• Carnivorous
• Legs are set at right angles to the body

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Characteristics of Amphibians

• 3 orders (continued)
• Anura (frogs and toads)
• Long hind legs w/ smooth moist skin (frogs)
• Short legs w/ bumpy dry skin (toads)
• Eat insects
• Some secrete chemicals through skin
• Have vocal chords
• Apoda (legless caecilians)
• No limbs w/ short or no tail
• Small eyes that are often blind
• Eat earthworms and other invertebrates found in
  soil

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31-1 Reptiles
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What is a Reptile?

• Class Reptilia
• Means to creep
• First animals to adapt to land
• Have dry scaly skin w/ claws
• Have lungs
• Most have 3 chambered heart some have 4
  chambered heart (crocodilians)

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• Ectotherms (cold blooded)
• Most are herbivores but some are carnivores
• Internal fertilization (sexually)
• Lay eggs on land (amniotic eggs)
• Provides nourishment and protection to developing
  embryo
• Use sense organs to detect prey or ID chemicals

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Characteristics of Reptiles

• 4 orders
• Squamata (snakes and lizards)
• Lizards live on the ground, burrows, trees or
  water
• Snakes - have no limbs kill prey by constriction
  or venom and swallowing whole
• Testudines (turtles and tortoises)
• Protected by a 2-part shell
• Some are aquatic,
  others are terrestrial
• No teeth but powerful jaws
  w/ beak-like structure
• Most are herbivores

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Characteristics of Reptiles

• 4 orders (continued)
• Crocodilia (crocodiles and alligators)
• Crocodiles have long slender snouts
• Alligators have short broad shouts
• Fresh and salt water
• 4 chambered heart
• Spenodonta (tuatara)
• Only survivor of primitive group of reptiles

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31-2 Birds
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Characteristics of Birds

• Class Aves
• Feathers, wings and thin
  hollow bones which allow for flight
• Keel shaped sternum
• 4 chambered heart
• Respiratory systems consist of lungs, anterior
  and posterior air sacs
• Endotherms (warm blooded)
• Able to regulate their internal body temperature

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Characteristics of Birds

• Internal fertilization (sexual)
• Amniotic eggs w/ hard shell
• Incubate their eggs (keep at a consistent
  temperature)
• Adaptations of birds
• Feathered legs and feet of ptarmigans
• Modified wings and feet of penguins
• Large eyes, acute sense of hearing and sharp
  claws of owls
• Long beaks of hummingbirds

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Pictures of Birds
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32-1 Introduction to the Mammals
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Characteristics of Mammals

• Meaning mamma breast
• Have hair
• Provides insulation and water proofing
• Endotherms (warm blooded)
• Feed young w/ milk from mammary glands
• Respiratory system includes diaphragm and lungs

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Characteristics of Mammals

• Teeth modified according to type of food eaten
• Chisel-shaped for gnawing (beaver)
• Canines for tearing and puncturing (lion)
• Premolar molars for slicing, shearing, crushing
  and grinding (humans)
• Modified limbs
• Opposable thumb to grasp objects
• Ability to learn

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Characteristics of Mammals

• Complex nervous system and senses
• Have sweat, oil and scent glands
• 4 chambered heart

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32-2 Diversity of Mammals
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• Classified by how they reproduce
• 3 sub-classes (continued)
• Monotremes
• Mammals that reproduce by laying eggs
• Found only in Australia, Tasmania, and New Guinea
• Duck-billed platypus and spiny ant-eater

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• 3 sub-classes (continued)
• Marsupials
• Young have a short period of development within
  the mothers body followed by a second period of
  development inside a pouch made of skin and hair
  outside the mothers body
• Kangaroos, opossum, spotted cuscus, and giant
  anteater
• Most found in Australia

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Pictures of Marsupials
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• 3 sub-classes
• Placental mammals
• Carry young inside of uterus until development is
  nearly complete
• Young are nourished via placenta
• Time inside the placenta is known as gestation
• 95 of all mammals
• Humans (9 months), elephants (22 months), dogs (9
  weeks), bison (9 ½ months), lions (4 months),
  and dolphins (12 months)

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Pictures of Placental Mammals
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Animal Behavior

• Chapter 34

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Terminology

• Behavior
• Anything an animal does in response to a stimulus
  in its environment
• Innate behavior
• Inherited behavior of animals (instinctive)
• Ex. The way a toad catches its prey.
• Fight-or-flight response
• Preparation of the body to either fight or run
  from the danger
• Controlled by hormones

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Terminology

• Instinct
• A complex pattern of innate behavior that begins
  with a stimulus and continues until all responses
  have been completed
• Ex. Migration, aggressive behavior, courtship
  behavior, circadian rhythm, and territorial
  behavior
• Circadian rhythm
• A 24-hour cycle of behavior, cycle of sleeping
  and wakefulness
• Mimicry
• The resemblance of one organism to another or to
  an object in its surroundings for concealment and
  protection from predators

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Terminology

• Migration
• The instinctive seasonal movement of animals
• Ex. Birds, Pacific salmon
• Hibernation
• A state in which the body temperature drops
  substantially, oxygen consumption decreases, and
  breathing rates decline to a few breaths per
  minute in order to conserve energy
• Ex. Bears
• Habituation
• A repeated stimulus that the animal finally
  ceases to respond to

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Terminology

• Imprinting
• When an animal at a critical time of its life
  forms a social attachment to another object
• Ex. Ducklings attachment to its mother
• Conditioning
• Learning by association
• Insight
• Learning when an animal uses previous experiences
  to respond to a new situation