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CHORDATA
• Animals with spines
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
• The VertebratesSUBPHYLA
•
OF THE PHYLUM
Sub Phylum Vertebrata– cartilaginousCHORDATA
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
paired fins, no true teeth or jaws
•
•
•
•
•
Skeleton Type: fibers and cartilage
2 chambered
Temperature control: ectotherm
Respiration: gills
Reproduction: sexually-external/
internal fertilization (oviparous)
• Importance: lamprey are parasites
and hagfish are decomposers that
feeding on dead or decaying fish)
VERTEBRATES –
CLASS CHONDRICHTHYES
• Examples: Sharks, Rays, Skates
• Chondros (Gk = cartilage)
• Body Plan: large curved tails, torpedo-shaped body,
pointed snout, moveable jaw, placoid (rough as
sandpaper)scales
• Skeleton Type: cartilage
• 2 chambered
• Temperature control:
ectotherm
• Respiration: gills
• Reproduction: sexually- external/internal fertilization
(oviparous/ovoviviparous/some viviparous)
• Importance: predators in the food chain
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: sexuallyexternal fertilization(97% are oviparous)
• Importance: prey in the food chain, fishing industry
• Saltwater
BONY FISH TYPES
• 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.
VERTEBRATES - REPTILIA
• Examples: snakes, lizards, turtles & tortoises, crocodiles
• 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: sexuallyinternal fertilization – eggs laid on land(most oviparous/ some ovoviviparous)
• Importance: control rat populations, medical use/research, clothing industry
Turtles make
a nest and
lay their eggs
on land.
Snakes are carnivorous and stretch
their jaws to consume their prey
whole.
The sex of a crocodile is determined
by temperature, with males
produced at 88 F, and females
produced at 80 F and 93 F.
https://www.youtube.com/watch?v=R
G1HRZvYb3M
LOGGERHEAD TURTLE
•Caretta caretta- one of the
largest, most abundant sea
turtles
KEMP’S RIDLEY TURTLE
•Lepidochelys kempii -
Endangered, smallest of sea
turtles, feeds mostly on crabs
LEATHERBACK TURTLE
•Dermochelys coriacea -
largest turtles on Earth, growing
up to seven feet long and
exceeding 2,000 pounds
SEA TURTLES
•Bodies enclosed in a
carapace (top shell)
that is fused to their
backbone
•Cannot retract their head
into their shell
•Legs are modified into
flippers for swimming
•Migrate long distances to
reproduce
•7-8 species
•Most live in warm waters
•Do not have teeth,
but have strong jaws
•Females lay 100-160
eggs in a nest that
hatch about 60 days
later
•Green turtle is hunted
mostly for meat and
cartilage for turtle
soup
•TEDS – turtle exclusion
device mandated by
US government for
shrimp nets
NESTING
•Very little is known why sea
turtles nest on some
beaches, and not on
others
•Most females return
faithfully to the same
beach each time they
nest
•Females nest usually
at night
•“false crawl” – occurs
when female turns
back and decides
not to nest
INCUBATION &
EMERGENCE
•About 60 days
•The hotter the sand, the faster
they hatch
Warmer
sand – more
females
Cooler sand – more males
•Hatchlings use a
temporary, sharp
egg-tooth called a
“caruncle” to break
open the shell
•Caruncle then falls off
•Digging out of the nest is
a group effort that takes
days
•Emerge from nest in a
group
•Orient themselves to
the brightest horizon
•Only about 1 in 1000
survives to adulthood
VERTEBRATES – AMPHIBIA (“DOUBLE-LIFE”)
• Examples: frogs, Toads, newts, salamander
• As larvae usually live in water and as adult live on land
• Body Plan: moist skin with mucous glands, lack
scales/claws, undergo metamorphosis
• Skeleton Type: hard, calcified tissue called bone
• 3 chambered
• Temperature control:
ectotherm
• Respiration: young=gills
adult=lungs
• Reproduction: sexuallyexternal fertilization(oviparous) or internal (salamanders)
• Importance: control insect populations, medical/
pharmaceutical use, food source (frog legs) in India/Asia
FROG METAMORPHOSIS
VERTEBRATES – AVES (BIRDS)
• Examples: chickens, penguins, cardinals, ostrich
• Body Plan: feathers of protein/keratin (flight/warmth),
two legs covered in scales, front limbs modified into
wings, thin hollow bones (helpful for flying)
• Skeleton Type: hollow, calcified tissue called bone
• 4 chambered
• Temperature control:
endotherm (can generate own body heat)
• Respiration: lungs, includes
passageways of air through air sacs
• Reproduction: sexuallyinternal fertilization - oviparous
• Importance: control insect populations, food source, clothing,
bedding, hunting purposes
AQUATIC BIRDS HAVE SPECIAL
ADAPTATIONS…
• 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 – warmblooded
•Covered with waterproof
feathers to conserve body
heat
Most can fly
Nest on land, many
forming huge
colonies
Have webbed feet
http://video.national
geographic.com/vid
eo/index.html
• Feed mostly at sea
• Worldwide distribution
• Only 3% of total bird population
• High metabolism – eat up to their
body weight a day
PENGUINS
• Native to Southern Hemisphere.
Most northerly population lives in
Galapagos Islands.
• The bird most fully adapted for sea
life
• flightless
• Great swimmers
• Adapted for cold by storing fat
under skin
• Dense feathers
hold in body heat
• 18 species
• Most are native to
Antarctica
• Establish breeding colonies, with
some mating for life
EMPEROR PENGUIN
•Largest
•45 inches tall
PELICANS
• Have a pouch
below their beak.
• Most scoop
fish from the
water
BROWN PELICAN
Almost extinct
because of
pesticide pollution
Nest in large,
messy, twiggy
nests along the
coast
• Brown Pelican plunges in the
water to catch their food. If they
don’t catch it directly, the shock
stuns the fish
GULLS
• Largest family of seabirds
• Predators and scavengers
http://video.nationalge
ographic.com/video/
3 CATEGORIES OF MARINE BIRDS
1. Shore birds
2. Water birds
3. Sea birds
1. SHOREBIRDS
•Wading birds
•Live mostly inland: estuaries
and marshes
Sandpipers
Plovers
2. WATER BIRDS
• Live in coastal and continental
interiors, but require water
for feeding and nesting
Ducks
Loon
Cormorant
3. SEA BIRDS
• Live on and around the sea
ALBATROSSES
•Nest on land, live at sea
•Wingspans can reach 11 feet.
http://video.nationalgeographic.c
om/video/index.html
ARCTIC
TERNS
• Have the greatest migration of any
bird. They venture from pole to pole
every year- a voyage of 22,000 miles.
Hazards for Sea Birds
Plastic 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.
http://player.discoveryeducation.co
m/index.cfm?guidAssetId=5EB7F6AC44B0-4E2E-A4CC1C9411BE3ED7&blnFromSearch=1&pr
oductcode=US
VERTEBRATES MAMMALIA
• Examples: cats, whales, gorillas, zebras, humans
• Body Plan: mammary glands (produce milk to nourish the
young), have hair, breathe air, bear live young
• Skeleton Type: hard, calcified tissue called bone
• 4 chambered
• Temperature control:
endotherm (can generate
own body heat)
• Respiration: lungs
• Reproduction: sexuallyinternal fertilization (viviparous)
• Importance: food, hunting, clothing, medical research, pets
MAMMALIA REPRODUCTION
DIVERSITY
• Monotreme – “egg-laying
mammal”; like reptiles
except after eggs hatch the
young is nourished by
mother’s milk
• Only 3 species exist: duckbill
platypus, 2 spiny anteaters
• Marsupial – bear live young
that complete their
development in an external
pouch
• Kangaroos, koalas, wombats
• Placental – nutrients, O2,
CO2, wastes are
exchanged b/n embryo
and mother through
placenta
• Elephants, rabbits, humans