Transcript Kingdom Animalia IV - Valhalla High School

Kingdom Animalia IV
Phylum Chordata
What are chordates?
• Chordates are animals that possess at some
point in their life, a hollow dorsal notochord,
pharyngeal pouches and a tail.
• The most primative chordates are actually
invertebrates called tunicates and lancets.
• These invertebrates possess a hollow dorsal
notochord as larva only.
Chordate evolution
• So how did animals with backbones arise
from tunicates?
• Biologists believe that at some point a larval
tunicate or lancet failed to metamorphose into
its adult form, and instead reproduced in it’s
juvenile form.
• This process by which juvenile traits are
carried on into adulthood is called
Paedomorphosis.
Tunicates
• The image on the left is the tunicate larva,
and on the right is the adult form.
The Vertebrates
• The majority of
chordates fall into 5
classes.
• Fish
• Amphibians
• Reptiles
• Birds
• Mammals
A 6th class of vertebrate?
• Depending on who is doing the classification,
some biologists believe dinosaurs were a
separate class of vertebrate.
• It is believed dinos evolved from reptiles, and
that some dinosaurs are the ancestors of
birds.
• The dino-bird link is based on anatomical
similarities in their skeletons, as well as
fossilized impressions of feathers around
dinosaur fossils.
• dinos to birds
Archeopteryx
Vicious Fishes
• Fishes are aquatic vertebrates.
• Most fish have paired fins, scales and gills.
• There are three major groups of fish.
– Agnathans: Jawless fish like lampreys.
– Chondricthyes: Fish with a skeleton made of
cartilage instead of bone, like sharks and rays.
– Osteichthyes: The bony fish like tuna.
Go fish
• The fish were the first vertebrates to evolve
on earth over 500 million years ago.
Waaaaaaaay before dinosaurs arrived.
• Important developments include jaws (which
arose from gill arches) and teeth (modified
scales).
• Fish use their gills to extract oxygen from the
water in which they live.
Types of fish
Jawless fish
Cartilage skeleton
Bony fish (tuna)
• Fish evolution
Amphibians
• The word amphibian means double life.
• An amphibian is a vertebrate that, with some
exceptions, lives in water as a larva and on
land as an adult, breaths with lungs as an
adult, has moist skin that contains mucous
glands, and lacks scales and claws.
• Amphibians represent the first class of
chordates to adapt to living on land.
• All amphibians are carnivorous.
Groups of amphibians
• There are 3 categories of amphibians.
– Salamanders: four legged and
carnivorous. Most adults live in moist
forest areas. Some types live in water their
whole lives.
– The Hellbender, the largest north american
salamander is fully aquatic and can be two
feet long.
Frogs and toads
• Frogs and toads are very similar in
appearance.
• They are four legged with the hind legs
being much larger and more muscular.
• Frogs and toads both lay eggs in water.
• Frogs are more closely tied to water,
while toads can live in more arid
conditions.
Caecillians
• The least well known group of
amphibians.
• Caecillians are legless like snakes and
live in either water or moist sediments.
• They feed on small invertebrates like
termites.
The amphibian delegation
Caecillian
Hellbender
(salamander)
Green tree frog
• amphibian evolution
Reptiles
• Reptiles are the first vertebrates to
completely lose their dependence on
water for reproduction.
• A reptile is a vertebrate that has dry,
scaly skin, lungs, and terrestrial eggs
with several membranes.
• It is believed that dinosaurs and
mammals both evolved from reptiles.
Reptile groups
• There are four orders of reptiles
– Lizards and snakes
– Crocodilians
– Turtles and tortoises
– Tuatara
Lizards and snakes
• Lizards are four legged, scaly reptiles with
external ears, claws and eyelids.
• Most are predators, though some are
herbivores.
The largest living lizard, the komodo dragon,
occasionally preys on humans.
• Snakes have lost their limbs during their
evolutionary history.
• All snakes are predatory and some, like the
cobra, produce venom. However, the
majority of snakes are harmless to humans.
Crocodilians
• Crocodilians include crocodiles, alligators,
caiman and gavials.
• They possess a squat muscular body, and
are all top predators. Even humans are on
the menu for some species.
• Crocodilians are very protective of their
young and will defend them against
predators.
Turtles and tortoises
• These reptiles have evolved a shell for
protection from predators.
• Many species can completely retreat inside
their shell when threatened.
• They lack teeth, but possess horny ridges
and strong jaws.
• This order has adapted to live in a wide range
of habitats.
• Some are carnivores and others are
herbivores.
Tuatara
• There is only one species in this order
still on Earth today.
• It lives on some islands in New Zealand.
• Very similar to lizards, but lack ears and
possess very primative scales.
Reptile representatives
• reptiles
Tuatara
The birds
• Birds are reptilelike animals that
maintain a constant internal body
temperature.
• They possess feathers.
• They have scaly legs and their front
limbs have been modified into wings.
• Most birds have the ability to fly.
Birds
• The birds share some similarities with
reptiles.
• The eggs of birds and reptiles are
similar, with the main difference being
that bird eggs have a hard outer shell.
• The scales on bird legs are very similar
to reptile scales.
• Unlike reptiles, birds are warm-blooded.
Classes of birds
• There are several different groups of birds.
Some examples are:
– Raptors: predatory birds like hawks, eagles and
falcons. They have hooked beaks and strong
talons.
– Perching birds: the songbirds like cardinals and
mockingbird. The largest order of birds.
– Herons: Tall longlegged birds with long sword like
beaks for catching fish and frogs.
A bevvy of birds
• Bird evolution
Mammals
• All mammals have hair and, in females,
mammary glands.
• They all breathe air, have a fourchambered heart, and are warm
blooded. (Endothermic)
• Mammals evolved about 220 million
years ago, about the same time the
dinosaurs appeared.
Humble beginnings
• The first mammals were very small and
probably nocturnal.
• When the dinosaurs ruled the earth,
mammals did their best to remain out of sight.
• Some biologists believe that if the dinosaurs
hadn’t perished 65 million years ago, it would
have been the mammals that became extinct.
Living fast
• Like the birds, mammals generate their
own body heat. Because of this both
mammals and birds have a high
metabolic rate when compared to cold
blooded animals.
• This means that mammals need to eat a
lot to get all the energy they need.
Reproduction
• All mammals reproduce by internal
fertilization, which means the male deposits
sperm into the females reproductive tract.
• There are 3 groups of living mammals.
– Monotremes (egg laying mammals, like the
platypus)
– Marsupials (mammals with pouches for their
developing young, like kangaroos).
– Placentals (animals who nourish their developing
young with a placenta, like humans).
12 orders of mammal
• Some examples are
– Rodents: Rats, mice, beavers and
porcupines.
– Carnivores: Cats, dogs, hyenas.
– Cetaceans: Whales and dolphins.
– Primates: Apes, Chimps and Humans.
– Chiropterans: The flying mammals.
Mammals
• evolution of
mammals