Phylum Chordata A Chordate is an animal that has 4 specific characteristics during their life cycle: 1- Dorsal, hollow nerve cord 2- Notochord – a long supporting rod that runs through the body below the nerve cord 3- Post anal tail 4-Pharyngeal pouches (gill slits)
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Phylum Chordata A Chordate is an animal that has 4 specific characteristics during their life cycle: 1- Dorsal, hollow nerve cord 2- Notochord – a long.
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Phylum Chordata A Chordate is an animal that has 4
specific characteristics during their life cycle: 1- Dorsal, hollow nerve cord 2- Notochord – a long supporting rod
that runs through the body below the nerve cord
3- Post anal tail 4-Pharyngeal pouches (gill slits)
1- A Dorsal, Hollow Nerve Cord This is a sheath of large nerve cells These nerve cells are somewhat like
stem cells in they may play an important role in other nerve cells that develop Example: certain motorneurons are
affected by the absence of these cells in embryonic development
In higher organisms, the actual “spinal cord” is surrounded by this hollow covering.
2- A Notochord The notochord is a strong structural
part of the organism It is located dorsally from the gut
(endoderm and coelom) It is made of cartilage or bone It is the spine, or vertebral column
3- A Post Anal Tail
Post means it is located posterior to the anus, or behind the anus
It is an extension of the notochord, and made of cartilage or bone
4- Pharyngeal pouches These are located at the pharynx, or
throat, of a chordate They develop into the gills of fish and
juvenile amphibians In aquatic reptiles, birds and
mammals, they close during embryonic development and become the throat, while the nasal passageways develop
Subphyla of the Phylum Chordata
The Nonvertebrates: Sub Phylum
Urochordata tunicates or “Sea Squirts”
Sub Phylum Cephalochordata – lancelets
These are very simple chordates without spines
All are aquatic
Subphyla of the Phylum Chordata The Vertebrates
Sub Phylum Vertebrata– cartilaginous and bony fish, amphibians, reptiles, birds, mammals
These are chordates with spines of cartilage or bony tissue
Vocabulary Body temperature control:
Ectotherm – animals that rely on behavior and interactions with the environment (Cold-Blooded)
Endotherm – animals that generate their own body heat and control temp. from within (Warm-Blooded)
Vocabulary
Egg to Juvenile Method:
Oviparous – Eggs hatch outside the female body
Ex: Most Fish
Ovoviviparous – Eggs develop inside the female body and the young are live-born Ex: Some Sharks)
Viviparous – bear live young that are nourished directly by the mother’s body as they develop.
Ex: Whales, Otters
Vertebrates – Agnathans (jawless fish) Examples: Lamprey; Hagfish Body Plan: snake-like, no scales, no
As the front row of shark teeth are worn out, new teeth are continually replacing them. A shark goes through 20,000 teeth in its lifetime!!
A skate is shown in the top picture; a stingray below
Vertebrates – Osteicthyes (bony fish)
Examples: goldfish, perch, bass, trout Body Plan: lateral line (use this to sense motion of other
fish nearby), swim bladder (internal, gas-filled organ that adjusts buoyancy), scales
Skeleton Type: hard, calcified tissue called bone 2 chambered Temperature control: ectotherm
Respiration: gills Reproduction: sexually-
external fertilization(97% are oviparous)
Importance: prey in the food chain, fishing industry
Bony Fish Types Saltwater
Strictly live in water with dissolved salt content near seawater, about 35 ppt in the open ocean
Must regulate the loss of freshwater out of their bodies as natural osmosis and diffusion seek to balance salt concentrations within and surrounding their bodies
Ex: marlin, mullet, snapper; flounder Brackish water
Require salinities between 35 ppt and freshwater Many marine fry are hatched in brackish water then migrate to
open oceans as they mature Ex: fry; sheepshead, croaker
Freshwater Strictly live in freshwater Must regulate the increase of freshwater into their bodies as
natural osmosis and diffusion seek to balance salt concentrations within and surrounding their bodies
Ex: blue catfish; bluegill, hybrid bass
More Types of Fish
Catadromous These fish hatch in marine waters and then migrate
into freshwater to spend adulthood They return to marine waters to spawn Ex: Eels are the most common fish to do this, and
the Sargasso Sea, near the southern part of the Atlantic Gyre, is their famous spawning ground
Anadromous These hatch in freshwater and then migrate into
marine waters to spend adulthood They return to freshwater to spawn, and then usually
die Ex: Salmon, shad, smelt and sturgeon are examples.
Things you must know: Fish External Anatomy
All fins Lateral line Scale Type
Fish Internal Anatomy Fish Organ Systems
Fish Morphology Body Shape that indicates ecological niche
Fish Behaviors Mating, Territoriality, Parenting
Identifying and “Keying Out” Fish What class are they in
Body Plan: dry, leathery skin, thick scales made of karatin (smooth or rough), terrestrial, amniotic eggs (shell & membrane so egg can develop out of water)
Skeleton Type: hard, calcified tissue called bone 3 chambered except crocodiles with 4 chambered
Temperature control: ectotherm Respiration: lungs
Reproduction: sexually-
internal fertilization – eggs laid on land(most oviparous/ some ovoviviparous)
Importance: control rat populations, medical use/research, clothing industry
Their feathers are highly resistant to being wetted They usually have higher oil production than other
birds from glands at the base of the tail The oil is applied to the feathers during preening
Preening is birds grooming activity; they run their beak through their feathers to straighten and comb them
During preening oil is spread lightly over feathers to help keep them water resistant
Dry feathers Keep birds warm when in aquatic sites Are easier to use for flight (think about a paper
airplane that is dry vs. one that is wet!)
More special adaptations… Aquatic birds also have special
appendages… Feet are webbed for swimming Legs may be longer to wade in water Long toes spread out to distribute weight in mud Beaks are modifications like the following:
for grasping wet, slippery prey Hooked tips on eagles The huge “baskets” of pelicans, spear-like points in herons, cranes and egrets filters of flamingos Beaks modified into bills for duck- and goose-like
creatures for sifting worms and arthropods from mud, or for catching fish underwater
MARINE BIRDS
Class Aves
Endotherms – warm-blooded
Covered with waterproof feathers to conserve body heat
bird. They venture from pole to pole every year- a voyage of 22,000 miles.
Hazards for Sea BirdsPlastic debris- ingest plastic materials because it fills the stomach, but lacks nutrients and cannot be passed.
Oil slicks saturate the feathers, destroying the ability to insulate, let alone be able to fly. The loss of insulation alone can be fatal
The greatest danger to seabirds is…. rat and mouse invasions. The mice consume the bird’s eggs in huge numbers, causing significant bird population declines on some Pacific Islands.