Transcript 04 Chapter

Table of Contents
Chapter: Invertebrate Animals
Section 1: What is an animal?
Section 2: Invertebrate Animals
Section 3: Vertebrate Animals
What is an animal?
1
Animal Characteristics
• What makes an animal an animal?
• Animals are many-celled organisms that
are made of different kinds of cells.
• Most animal cells have a nucleus and
organelles. The nucleus and many
organelles are surrounded by a membrane.
This type of cell is called a eukaryotic
(yew ker ee AH tihk) cell.
What is an animal?
1
Animal Characteristics
• Animals cannot make their own food.
• Animals digest their food.
• Most animals can move from place
to place.
What is an animal?
1
Symmetry
• Symmetry refers to the arrangement of the
individual parts of an object that can be
divided into similar
halves.
• Animals with body
parts arranged in a
circle around a
central point have
radial symmetry.
What is an animal?
1
Symmetry
• Animals with bilateral
symmetry have parts that
are nearly mirror images
of each other.
• A line can be drawn down
the center of their bodies
to divide them into two
similar parts.
What is an animal?
1
Symmetry
• Some animals have an
irregular shape.
• They are called
asymmetrical (AY suh
meh trih kul).
• They have bodies that
cannot be divided into
similar halves.
What is an animal?
1
Animal Classification
• Scientists place all animals into smaller,
related groups.
• They can begin by
separating animals into two
distinct groups—vertebrates
and invertebrates.
• Vertebrates (VUR tuh bruts)
are animals that have a
backbone.
What is an animal?
1
Animal Classification
• Invertebrates (ihn VUR tuh bruts) are
animals that do not have a backbone.
• About 97
percent of all
animals are
invertebrates.
What is an animal?
1
Animal Classification
• Scientists classify the invertebrates into
smaller groups, as shown.
• The animals within each group share similar
characteristics.
Section Check
1
Question 1
How do animals get food?
Answer
Animals can not make their own food. They
must eat plants or other animals to supply their
energy needs.
Section Check
1
Question 2
Which has radial symmetry?
A. lobster
B. sea anemone
C. sponge
D. none of them
Section Check
1
Answer
The sea anemone has radial symmetry.
Symmetry refers to the arrangement of the
parts of an animal. Animals with radial
symmetry have body parts arranged in a circle
around a central point.
Section Check
1
Question 3
Which describes most of the cells found in
animals?
A. they have bilateral symmetry
B. they have a nucleus and many organelles
C. they help animals move
D. they help in reproduction
Section Check
1
Answer
The correct answer is B. The cells found in
animals are called eukaryotic cells. Animals
are made of many different kinds of cells.
Invertebrate Animals
2
Sponges
• Adult sponges are
sessile meaning they
remain attached to
one place.
• They are filter feeders,
filtering food out of
the water that flows
through their bodies.
Invertebrate Animals
2
Sponges
• Sponge bodies are made of two layers of
cells.
• The inner surface of the central cavity is
lined with collar cells.
• Thin, whip-like structures called flagella
extend from the collar cells and keep the
water moving through the sponge.
Invertebrate Animals
2
Body Support and Defense
• The soft bodies of many sponges are
supported by sharp, glass-like structures
called spicules.
• Other sponges have a material called
spongin. Spongin is similar to foam rubber
because it makes sponges soft and elastic.
Invertebrate Animals
2
Sponge Reproduction
• Sponges care reproduce asexually and
sexually. Asexual reproduction occurs when
a bud on the side of the parent sponge
develops into a small sponge.
Invertebrate Animals
2
Cnidarians
• Cnidarians such as
jellies, sea anemones,
hydra, and corals,
have tentacles
surrounding their
mouth.
• Cnidarians are hollow-bodied animals with
two cell layers that are organized into
tissues. The inner layer forms a digestive
cavity where food is broken down.
Invertebrate Animals
2
Cnidarians
• Cnidarians reproduce asexually and sexually.
Some reproduce asexually by budding.
• Some can reproduce sexually by releasing
eggs or sperm into the water.
Invertebrate Animals
2
Flatworms and Roundworms
• Flatworms are invertebrates with long,
flattened bodies ant bilateral symmetry.
• Their soft
bodies have
three layers of
tissue organized
into organs and
organ systems.
Invertebrate Animals
2
Flatworms and Roundworms
• A roundworm’s body is described as a tube
within a tube, with a fluid-filled cavity in
between the two tubes.
• Their digestive tract has two openings. Food
enters through the mouth, is digested in a
digestive tract, and wastes exit through the
anus.
Invertebrate Animals
2
Mollusks
• Mollusks are softbodied invertebrates
that usually have a
shell. They also have
a mantle and a large,
muscular foot.
• If the mollusk has a shell, it is secreted by
the mantle.
• The foot is used for moving or for anchoring
the animal.
Invertebrate Animals
2
Mollusks
• Mollusks have a digestive system with two
openings.
• Some mollusks have an open circulatory
system, which means they do not have
vessels to contain their blood.
• Others have a closed circulatory system, in
which blood is carried through blood vessels
instead of surrounding the organs.
Invertebrate Animals
2
Segmented Worms
• Earthworms, leeches, and marine worms are
segmented worms, or annelids.
• Each segment has nerve cells, blood vessels,
part of the digestive tract, and the coelom.
• The coelom, or internal body cavity,
separates the internal organs from the body
wall.
• Annelids have a closed circulatory system
and a complete digestive system with two
body openings.
Invertebrate Animals
2
Arthropods—Structure
and Function
• Arthropods are animals that have jointed
appendages.
• Appendages
are structures
such as claws,
legs, and
antennae that
grow from the
body.
Invertebrate Animals
2
Arthropods—Structure
and Function
• Arthropods have a rigid body covering called
an exoskeleton.
• They have an open
circulatory system,
and oxygen is brought
directly to the tissues
through spiracles.
Invertebrate Animals
2
Metamorphosis
• Many arthropods
completely change
their body form as they
mature. This change
in body form is called
metamorphosis.
• Complete
Metamorphosis has
four stages—egg,
larva, pupa, and adult.
Invertebrate Animals
2
Metamorphosis
• Incomplete
metamorphosis
has only three
stages—egg,
nymph, and
adult. A nymph
looks similar to
its parents, only
smaller.
Invertebrate Animals
2
Echinoderms
• Sea stars belong to
a varied group of
animals called
echinoderms.
• Echinoderms have spines of various lengths
that cover the outside of their bodies.
• All echinoderms have a water-vascular
system.
Section Check
2
Question 1
How do cnidarians use nematocysts?
Answer
Nematocysts, or stinging cells, are used to
capture prey.
Section Check
2
Question 2
This diagram of a sponge shows that sponges
_______.
Section Check
2
A. are hermaphrodites
B. produce buds
C. reproduce asexually
D. use spicules for production
Section Check
2
Answer
The correct answer is A. Most sponges that
reproduce sexually are hermaphrodites.
Both sperm and eggs are produced from the
same sponge.
Section Check
2
Question 3
Which of the following describes the body
of a roundworm?
A. a medusa
B. a polyp
C. a tube within a tube
D. has two cell layers
Section Check
2
Answer
The correct answer is C. The two tubes are
separated by a fluid-filled cavity. The inner
tube is the digestive tract.
Vertebrate Animals
3
What is a chordate?
• Three characteristics of all chordates are a
notochord, a nerve cord, and pharyngeal
pouches at some time during their
development.
• The notochord is a flexible rod that extends
along the length of the developing organism.
Vertebrate Animals
3
What is a chordate?
• Pharyngeal pouches are slitlike openings
between the body cavity and the outside of
the body.
• They are present only during the early stages
of the organism’s development.
Vertebrate Animals
3
Vertebrates
• Vertebrates have an internal system of bones
called an endoskeleton.
• The vertebrae, skull, and other bones of the
endoskeleton support and protect internal
organs.
Vertebrate Animals
3
Body Temperature
• Most vertebrate body temperatures change as
the surrounding temperature changes. These
animals are ectotherms or cold-blooded
animals.
• Humans and many other vertebrates are
endotherms or warm-blooded animals.
Their body temperature doesn’t change with
the surrounding temperature.
Vertebrate Animals
3
Fish
• There are three classes of fish: jawless, jawed
cartilaginous, and bony. Fish are ectotherms
that can be found in warm desert pools and
the subfreezing Artic Ocean.
Vertebrate Animals
3
Fish
• Fish have fleshy
filaments called
gills where carbon
dioxide and oxygen
are exchanged.
Vertebrate Animals
3
Fish
• Most fish have pairs of fanlike fins. The top
and the bottom fins stabilize the fish. Those
on the sides steer and move the fish.
• Most fish have scales.
• Scales are thin
structures made of
a bony material that
overlap like
shingles on a house
to cover the skin.
Vertebrate Animals
3
Amphibians
• Amphibians are animals that spend part of
their lives in water and part on land.
• Frogs, toads,
newts, and
salamanders
are examples
of amphibians.
Vertebrate Animals
3
Amphibian Characteristics
• Amphibians are vertebrates with a strong
endoskeleton made of bones.
• Adult amphibians use lungs instead of gills to
exchange oxygen and carbon dioxide.
Vertebrate Animals
3
Amphibian Characteristics
• Because amphibians have three-chambered
hearts, the blood carrying oxygen mixes with
the blood carrying carbon dioxide.
• Adult amphibians also exchange oxygen and
carbon dioxide through their skin, which
increases their oxygen supply.
Vertebrate Animals
3
Reptiles
• Reptiles are ectothermic vertebrates with dry,
scaly skin.
• Because reptiles
do not depend
on water for
reproduction,
most are able to
live their entire
lives on land.
Vertebrate Animals
3
Reptile Adaptations
• All reptiles have lungs for exchanging
oxygen and carbon dioxide.
• Reptiles also have a neck that allows them to
scan the horizon.
Vertebrate Animals
3
Reptile Adaptations
• Two adaptations enable reptiles to reproduce
successfully on land—internal fertilization
and laying shell-covered, amniotic eggs.
• The embryo develops
with the moist protective
environment of the
amniotic egg.
• When eggs hatch, young
reptiles are fully developed.
Vertebrate Animals
3
Birds
• Birds are endothermic vertebrates that have
two wings, two legs, and a bill or beak.
• Birds are covered mostly with feathers.
• They lay hardshelled eggs
and sit on these
eggs to keep
them warm
until they hatch.
Vertebrate Animals
3
Adaptations for Flight
• The bodies
of most
birds are
designed for
flight.
• The inside of a bird’s bone is almost hollow.
Internal crisscrossing structures strengthen
the bones without making them as heavy as
mammal bones are.
Vertebrate Animals
3
Adaptations for Flight
• Birds eat insects, nectar, fish, meats, or other
high-energy foods.
• They also have a large, efficient heart and a
specialized respiratory system. A bird’s lungs
connect to air sacs that provide a constant
supply of oxygen to the blood and make the
bird more lightweight.
Vertebrate Animals
3
Functions of Feathers
• Strong, lightweight contour feathers give
adult birds their stream-lined shape and
coloring.
• Outer contour feathers help a bird move
through the air or water.
• Birds have down feathers that trap and keep
warm air next to their bodies. These fluffy
feathers provide an insulating layer under the
contour feathers of adult birds and cover the
bodies of some young birds.
Vertebrate Animals
3
Mammals
• Mammals are
endothermic
vertebrates. They
have mammary
glands in their skin.
• In females, mammary
glands produce milk
that nourishes the young.
• A mammal’s skin usually is covered with hair
that insulates its body from cold and heat.
Vertebrate Animals
3
Different Teeth
• Plant-eating animals are called herbivores.
Animals that eat meat are called carnivores,
and animals that eat plants and animals are
called omnivores.
• Mountain lions are
carnivores. They
have sharp canines
that are used to rip
and tear flesh.
Vertebrate Animals
3
Different Teeth
• Humans are omnivores.
They have incisors that
cut vegetables,
premolars that are sharp
enough to chew meat,
and molars that grind
food.
Vertebrate Animals
3
Different Teeth
• Herbivores,
like this
beaver, have
incisors that
cut vegetation
and large, flat
molars that
grind it.
Vertebrate Animals
3
Body Systems
• Mammals have well-developed lungs made
of millions of microscopic sacs called alveoli,
which enable the exchange of carbon dioxide
and oxygen during breathing.
• They also have a complex nervous system
and are able to learn and remember more than
many other animals.
• All mammals have internal fertilization.
Vertebrate Animals
3
Mammal Types
• Monotremes make up the smallest group of
mammals.
• They lay eggs with tough, leathery shells
instead of having live births.
Vertebrate Animals
3
Mammal Types
• Marsupials live in
Australia, Tasmania,
and New Guinea. The
opossum is the only
marsupial that lives in
North America.
• Most marsupials carry
their young in a pouch.
Vertebrate Animals
3
Placentals
• Placentals are named for the placenta,
which is a saclike organ that develops from
tissues of the embryo and uterus.
• An umbilical cord connects the embryo to
the placenta.
• Food and oxygen from the mother’s blood
are carried to the developing young by the
blood vessels in the umbilical cord.
Section Check
3
Question 1
_______ is the internal system of bones in
vertebrates.
Answer
The answer is endoskeleton. The endoskeleton
supports and protects the internal organs.
Section Check
3
Question 2
Which is the largest group of vertebrates?
A. cats
B. dogs
C. fish
D. humans
Section Check
3
Answer
The answer is C. Fish are ectotherms and
live in water.
Section Check
3
Question 3
This illustration shows a typical body structure
of what classification of fish?
A. bony
B. cartilaginous
C. jawless
D. scale less
Section Check
3
Answer
The answer is A. About 95 percent of all
fish have skeletons made up of bone.
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