Fishes, Amphibians, Reptiles - WA Eagles 220€¦ · Fish, reptiles, amphibians Animal whose body...
Transcript of Fishes, Amphibians, Reptiles - WA Eagles 220€¦ · Fish, reptiles, amphibians Animal whose body...
Fishes, Amphibians, Reptiles
Section 1: What is a Vertebrate? Characteristics of
CHORDATES
Most are Vertebrates (have a spinal cord)
Some point in life cycle all chordates have:
Notochord
Nerve cord that runs down their back (like a spinal cord)
Slits in their throat area
NOTOCHORD
Flexible rod that supports a chordate’s back
Lancelet has a notochord its whole life
All vertebrates have part or all of notochord replaced with a backbone
SLITS in Throat Area
Also called Pharyngeal slits (or gill slits)
Fish have them their whole life
In humans, they disappear before birth
Characteristics of Vertebrates Most chordates
Has backbone that is part of an internal skeleton
Backbone = spine
Formed by bones called vertebrae
Joints in between each bone provide flexibility
Hole through each vertebrae for spinal cord
Makes up part of endoskeleton
Protects internal organs
Gives body its shape
Does not need to be replaced
Location for muscle attachment
Allows greater growth
Keeping Conditions Stable Ectotherms
Fish, reptiles, amphibians
Animal whose body does not produce much internal heat
Body temperature changes based on temperature of the surrounding environment
Endotherms
Birds and mammals
Animals that regulate their own body temperature
Adaptations including sweat glands, fur/feathers
Larger variety of suitable living environments
Section 2: Fishes Aquatic vertebrate with fins
Most are ectotherms
Obtain oxygen through gills
Have scales
Largest group of vertebrates
Three major groups:
Jawless
Cartilaginous
Bony
Obtaining Oxygen Fish opens its mouth and
take a gulp of water
Water moves through throat and then to gills
Gills contain many blood vessels
Oxygen diffuses into blood vessels
Carbon dioxide diffuses out
Water flows out of slits beneath the gills
Circulatory System
Oxygen-rich blood travels through closed system
Two-chamber heart
Pumps blood in one loop
Heart gills rest of body back to heart
Reproduction External fertilization
Eggs fertilized outside of female’s body
Male hovers close to female
Male spreads a cloud of sperm cells over released eggs
Young develops outside of female’s body
Internal fertilization- sharks, guppies
Eggs fertilized inside of female
Female gives birth to offspring
Jawless Fish No jaws and no scales
Mouths designed for scraping, stabbing, and sucking their food
Hagfishes- scavengers w/ large, slimy worm-like bodies
Lampreys- Parasites of other fish
Cartilaginous Fish Skeletons made of cartilage
Have jaws and scales
Sharks, rays, skates
Usually carnivores
Rays and skates- hunt on ocean floor for mollusks, crustaceans, and small fish
Sharks- attack and eat anything that smells like food
Used jagged teeth arranged in rows
Only front teeth are used for feeding
Teeth move forward if front teeth are lost
Bony Fishes 95% of all fish
Trout, tuna, goldfish
Skelton made of hard bones
Scales and a jaw
Pocket on each side of the head that hold the gills
Swim bladder
Internal, gas-filled sac
Helps stabilize fish at different depths
Section 3: Amphibians Means “double life”
Beginning of life in water, adult life on land
Return to water to reproduce
Ectothermic vertebrate
Two groups:
Salamanders- keep tails in adulthood
Frogs and toads- no tail in adulthood
Reproduction and DevelopmentFROGS SALAMANDERS
-Eggs are fertilized externally and developin water-Larvae wriggle out of jelly that coat the eggs-TADPOLES = frog larvae-Begin a free-swimming fish-like life
-Eggs are fertilized internally-Larvae looks like adults-During metamorphosis, they lose their gills-Changes during metamorphosis are not as dramatic
Living on Land When amphibians become adults, multiple
adaptations occur:
Lose gills and develop lungs for gas exchange
Circulatory system changes from single loop with a 2-chamber heart to two loops with a 3-chamber heart
Atria- two upper chambers
Left gets blood from lungs
Right gets blood from body
Ventricle- lower chamber
pumps blood out to both
lungs and body
More Adaptations Change from herbivores to carnivores
Develop camouflage to help obtain food
Develop skeletons and muscular limbs
Powerful hind-leg muscles for jumping
Skelton to absorb shock when landing
Changes to the feet
Webs to aid in swimming
Sticky pads for climbing
Section 4: Reptiles Ectothermic vertebrates with lungs and scaly skins
Snakes, lizards, turtles, alligators
Can spend entire life on land
Adaptations for water conservation:
Dry, tough skin with scales
Kidneys filter wastes which are excreting as urine
Amniotic egg prevents embryo from drying out
Amniotic Egg Reptiles exhibit internal
fertilization
Lay eggs on land
Egg contain shell and 4 internal membranes
Shell has pores for gas exchange
4 Membranes for:
Holding liquid that surrounds embryo
Holding yolk (food for embryo)
Holding embryo’s wastes
Exchange of O2 and CO2
Lizards Skin with overlapping
scales
Shed their skin and scales as they grow
4 legs with claws on toes
Long tails, external ears, movable eyelids, two lungs
Carnivores that jump at their prey
Eat frogs, birds, insects depending on size
Snakes Identical skin qualities as lizards
No legs, streamlined bodies, no external ears or eyelids
Most have only one lung
Eat small animals like mice
Use long front teeth for hooking
Some inject venom via their fangs
Jawbones can spread apart
Skull bones can move to swallow large prey
Alligators and Crocodiles Largest living reptiles
Take care of their young
Carnivores that hunt at night
Hunting/Eating adaptations include:
Strong, muscular tails fro swimming
Jaws with large, sharp, pointed teeth
Strong jaw muscles for biting down
Alligator and Crocodile Reproduction Care for eggs and newly hatched young
Female stays near the nest
Periodically, she will crawl over nest from the water to keep it moist
Once eggs hatch, mother will scoop them up in her mouth and carry them away to a safe area in the water
May stay with young up until a year or when they can feed and protect themselves
Turtles Reptile covered by
protective shell w/ ribs and a backbone
Shells are either hard or soft
Some can bring head, legs, tail inside for protection
Tortoises = land turtles
Have sharp-edged beak instead of teeth for eating
Can be carnivores or herbivores
Extinct Reptiles- Dinosaurs
Ancestors of reptiles
Extinct 65 million years ago
Some may have been endothermic
Herbivores walked on 4 legs
Carnivores walked on 2 legs
Section 5: Vertebrates History in Rocks What are Fossils?
Hardened remains of living things
Bones, shells, skeletons
Tissues are replaced by hard minerals
Found in sedimentary rocks
Layered rocks containing particles of:
Clay
Sand
Mud
Silt
More on Fossils Paleontologist = scientists who study extinct
organisms by:
Examining fossil structures
Making comparisons to present-day organisms
Can determine approximate age by:
Studying sediment layers
Examining radioactive decay
Vertebrate Evolution Fish- 530 million years ago
Amphibians- 380 million
Reptiles- 320 million
Mammals- 220 million
Birds- 150 million
Birds and Mammals are both descendants of reptiles