Chapter 7
•Section 1
•What is an Animal?
Structure of Animals
• Animals are composed of many cells.
• Cell is the basic unit of structure and function
of in living things.
• Cell are organized into higher levels of
structure.
– Systems
• Organs
– Tissue
Structure of Animals
• Group of similar cells and specific function is
called a tissue
• Tissues can combine together to for an organ,
which is several different tissues.
• Ex. Stomach, made of muscle, nerve and other tissues.
• The stomach is then apart of the digestive
system.
Functions of Animals
• The major function of animals is to obtain
food and oxygen, keep internal conditions
stable, move, and reproduce.
• Adaptations are structures or behaviors to
perform basic functions in their environment.
• Animals must eat other organisms to live
• Animals are always on the move for food and
oxygen
Functions of Animals
• Animals must maintain stable cond. Otherwise
animal can’t survive.
• Animals are always moving.
• Ex. Dogs, cats, fish, etc…
• Some animals only move in early stage of life
– Ex. Barnacle
• Most animals reproduce sexually
• Sexual reproduction is the process that a new
org. develops from the joining of an egg and
sperm cell.
Functions of Animals
• Asexual reproduction is where a single
organism make a new organism identical to
Classification of Animals
• Biologists have already found and named 1.5
million animal species
• An animal is classified based on its looks, how
it develops and the contents of its DNA.
– Classification reveals its relationship to other
animals.
• There are 35 groups of animals put into
different groups called phylum
Classification of Animals
• Vertebrates are animals with a backbone.
• Invertebrates are animals without a backbone.
• 97% of all animals are invertebrates
•Section 2
•Animal Symmetry
The Mathematics of Symmetry
• The balanced arrangement of parts in an
animal and other objects is called symmetry
• Bilateral symmetry is one line dividing an
object into equal halves.
• Radial symmetry is many lines thru a central
point.
• Can infer some char. of animals based on their
symmetry.
Symmetry and Daily Life
• Animals with radial symmetry are like the
spokes of a bike wheel
• Most animals have bilateral symmetry
• Animals with bilateral symmetry are more
complex and larger
•Section 3
•Sponges, Cnidarians,
Worms and
Mollusks
Sponges
• Sponges are invertebrates are animals usually
without symmetry and have no tissues or
organs.
• Looks like a hollow bag with a large opening at
one end.
– Belongs to the phlya Porifera, meaning to have
pores.
• Sponge attaches itself to hard surfaces
underwater
Sponges
• Water carries food and oxygen to the sponge
• Water also helps sponges to reproduce
• Sponges can reproduce both sexually and
asexually
• In asexual reproduction, a new “bud” grows
out of the adult sponges side
• Bud eventually breaks free and grows up to be
an adult
Sponges
• Sponges are both boy and girl
• Sponges will produce both sperm and egg
cells
• Sperm is released from one sponge and enters
another sponge to fertilize with an egg
• A larva will form and then grow on its own
– Larva is an immature form of an animal that looks
very different from an adult
Cnidarians
• Cnidarians are invertebrate animals that use
stinging cells to capture food and defend
themselves
– Ex. Jellyfish, coral, and sea anemones
• Have 2 different body plans
– Medusa is bowl shaped and is adapted for
swimming life.
– Polyp is vase shaped with a mouth at the top
Cnidarians
• Cnidarians stinging cells are key to obtaining
food.
• Cnidarians also can reproduce sexually and
asexually
• Budding is the most common type of asexual
reproduction
• Sexual reproduction can occur in many ways
– Some have both sexes, some have separate sexes
and many have life cycles
Worms
• Biologists classify worms into 3 major phyla
– Flatworms, roundworms, and segmented worms.
• Flatworms belong to the phylum
Platyhelminthes
• Roundworms belong to the phylum belong to
the phylum Nematoda
• Segmented worms belong to the phylum
Annelida
Worms
• All worms are invertebrates with long narrow
bodies
• Worms are the simplest organisms with a
brain found in the head end
• Worms are able to reproduce both sexually
and asexually
Worms
• Flatworms
– Ex. Tapeworms, planarians, and flukes
– Flatworms are flat and soft, like jelly
– Flatworms are a parasite
• Parasites are organisms that live in or on another
organism
– A parasite takes food from its host
• A host is the organism that the parasite uses as a home
Worms
• Roundworms
– Roundworms have cylindrical bodies
– Roundworms have a digestive system that is open
at both ends
– This allows digestion to happen in orderly steps
• Allows for more absorption of food nutrients.
• Segmented worms
– Ex. Earthworms, leeches, and some sea-floor
worms
Worms
• Segmented worms
– Segmented worms have bodies made up of many
linked sections.
– On the outside the segments all look alike.
– Segmented worms have a closed circulatory
system
Segmented
Worms
Flat
Worms
Round
Worms
Long Flat
body
Long Round Long round
body made up
body
Food absorbed
through body wall, or
enters and exits same
opening
Food enters at
head, exits at
tail
Simplest kind of
animal with bilateral
symmetry
Among most
May be more closely
numerous of all types related to arthropods
of animals
than worms
of segments
Food enters at
head, exits at
tail
Mollusks
• Snails, slugs and octopuses are all
invertebrates
• Mollusks have soft, unsegmented bodies often
covered by sells and a thin layer of tissue
called a mantle
• The mantle covers the internal organs, and an
organ is called a foot
• Foot is usually adapted for different functions
Mollusks
• Mollusks have bilateral symmetry
• Mollusks are classified into 3 major groups
– Gastropods (Snails and Slugs)
– Bivalves (Clams and Oysters)
– Cephalopods (Octopuses and Squids)
• Gastropods are the largest group of mollusks
• Gastropods are mollusks that have a single
external shell or no shell at all
Mollusks
 Gastropods feed using a radula, a flexible
ribbon of tiny teeth
 Some gastropods are herbivores, animals that
eat plants.
 Bivalves are found in all kinds of watery
environments
 Bivalves are mollusks that have 2 shells held
together by hinges and strong muscles
Mollusks
Cephalopods are the only mollusks with a
closed circulatory system
A cephalopod is an ocean dwelling mollusk
whose foot is adapted to form tentacles
around its mouth.
Cephalopods swim by jet propulsion
They squeeze out a current of water out of the
space surrounded by the mantle.
Section 4
Arthropods and
Echinoderms
Characteristics of Arthropods
• Arthropods are invertebrates that have an
external skeleton , a segmented body, and
jointed attachments called appendages.
– Ex. Ants, Grasshoppers, Lobsters, Spiders.
• Arthropods have bilateral symmetry, an open
circulatory system, and a digestive system
with 2 openings.
• Most arthropods reproduce sexually
Arthropods
• Scientists have identified more than 1 million
species of arthropods
• More than all other species combined
• As arthropods grow larger, their waxy
exoskeleton can’t expand
– Exoskeleton is like a suit of armor
• The process of shedding the exoskeleton is
called molting
– After molting, exoskeleton is soft for a short time
Arthropods
• Arthropods have segmented bodies
• Many arthropods also have jointed
appendages attached to their bodies
– Fingers to your hands
• Arthropods have specialized appendages
– For walking, obtaining food, reproducing, and
sensing the environment.
Insects
• The major groups of arthropods are Insects,
Crustaceans, Centipedes, and Millipedes.
• Insects are arthropods with 3 body sections, 3
pairs of legs, 1 pair of antennae, and usually 1
or 2 pairs of wings.
• The 3 body sections are the head, thorax and
abdomen
Insects
• The process in which an animals body goes
thru a dramatic change in its form during its
life cycle is called a metamorphosis
– Egg, larva, pupa, adult
Crustaceans
• Crustaceans are arthropods with 2 or 3 body
sections, 5 or more pairs of legs and 2 pairs of
antennae
– Ex. Shrimp, crab, crayfish and lobsters
• Crustaceans obtain food in many ways
– Many are scavengers
– Some are predators
• Most crustaceans begin life microscopic
– Go thru partial metamorphosis, larva into adults
Arachnids
• Arachnids are arthropods with 2 body
sections, 4 pairs of legs, and no antennae
– Ex: Spiders, mites, ticks and scorpions
• 2 body sections are a head/midsection and
the abdomen
• All spiders are predators
• Spiders have hollow fangs that inject venom
• Venom turns insect tissue to mush
Arachnids
• Fangs are then used like drinking straws
• Almost all spiders are harmless
– Brown recluse and black widow require hospital
• Ticks are parasites that live on the outside of
the host animal
• Nearly every type of land animal has a tick
that sucks its blood
Arachnids
•
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Scorpions live mostly in hot climates
Mostly active at night
During the day they hide in cool places
At the end of its abdomen is a spinelike stinger
Stinger is used to inject venom into its prey
– Usually a spider or insect
Centipedes and Millipedes
• Easy to count the legs on other Arthropods
• Not easy for centipedes or millipedes
• Both have 2 body sections and numerous pairs
of legs
• Head section has 1 pair of antennae
• Abdomen section with many segments
• Centipedes are swift predators
Centipedes and Millipedes
• Inject venom with pair of claws near mouth
• Millipedes have more than 80 segments and
each segment has 2 pairs of legs
• Most millipedes are scavengers
• Millipedes curl up into a ball when in danger
• Some also squirt an awful smelling liquid at a
potential predator
Echinoderms
• Echinoderms are in the phylum
Echinodermata
• Echinoderms are invertebrates with an
internal skeleton and a system of fluid filled
called a vascular system
• All echinoderms live in salt water
• The skin of most echinoderms is supported by
an internal skeleton called an endoskeleton
Echinoderms
• Adult echinoderms have a unique radical
symmetry in which body parts come in
multiples of 5’s and look like tire spokes
• Echinoderms have tube feet that are sticky
and act like suction cups
– By forcing water, contracting the feet
• Most are either male or female
Echinoderms
• Female releases her eggs into the water, male
fertilizes with his sperm
• Eggs develop into swimming larvae, undergo
metamorphosis into adults
• Share internal structures, do not look alike on
the outside
• Different ways of feeding and moving
• Major groups are the Sea Stars, Brittle Stars,
Sea Urchins, and Sea Cucumbers.
•Section 5
•Fishes, Amphibians,
and Reptiles
Characteristics of Chordates
• Members of the phylum Chordata are called
chordates
• At some point in its life, a chordate with have
a notochord, a nerve that runs down its back,
and a slit in its throat area.
– Ex: Fish, Amphibians, Reptiles, Birds, and
Mammals
• Chordates get their name from the notochord
Characteristics of Chordates
• The notochord connects the brain and nerves
• Chordates have slits in their throat area called
gill slits
• Invertebrate and some vertebrate chordates
keep their gill slits all their life
• In other vertebrates, gill slits disappear before
birth
Characteristics of Vertebrates
• Most chordates are vertebrates
• A vertebrate has a backbone that is part of an
internal skeletal system
• The backbone is formed by many bones called
vertebrae
• Each vertebrae has a hole in it to allow the
spinal cord to pass thru it
• The backbone protects the body, gives it
shape, and gives muscle a place to attach
Characteristics of Vertebrates
• Big difference between vertebrates is how
they control body temp.
• Fish, amphibians, and reptiles have body
temp. close to that of environment
• Birds and mammals can regulate and are
usually above that of environment
• Ectotherm has a changing body temp.
• Endotherm can regulate body temp.
Characteristics of Fishes
• Fish are largest group of vertebrates, half of all
vertebrates are fishes
• Fish live in water, have fins, most are
ectotherms, obtain oxygen thru gills, and have
scales
• Most fish reproduce by external fertilization
• In internal fertilization the egg is fertilized
inside the females body
Groups of Fishes
• Fish are classified into 3 major groups
– Jawless
– Cartilaginous
– Bony
• Jawless Fish
– Jawless fish are unlike other fish, no jaws and no
scales
– Jaws used for scrapping, stabbing, and sucking
their food.
Groups of Fishes
• Jawless Fish
– Skeletons are made of cartilage, tissue that is
more flexible than bone
• Cartilaginous Fish
– Ex: Sharks and rays
– Have jaws, scales, and skeletons of cartilage
– Scales are sharp
– Sharks must keep moving in order to breathe
– Rays can remain motionless
Groups of Fishes
• Cartilaginous Fish
– Most are carnivores
• Bony Fish
– Ex: Trout, tuna, and goldfish
– Make up 95% of all fish
– Have jaws, scales, gills, skeleton of bone
– Has a swim bladder to help stay stable
• Used to keep fish at a certain depth
Amphibians
• Ex: Salamanders, frogs and toads
• Amphibian means double life
• After beginning life in water, most spend
adulthood on land, returning to water to
reproduce
• Difference is salamanders keep their tail
• Amphibian eggs are coated with a clear jelly
• Amphibians go thru a metamorphosis
Amphibians
• Amphibians breathe with gills when young,
but use lungs when adults on land
• Lungs are organs of air-breathing vertebrates
• Also breathe thru their skin
• Frogs and toads wait for prey to come close
• Salamanders stalk their prey
Reptiles
• Reptiles are ectothermic vertebrates with
scaly skin that lay their eggs on land
• Reptiles have dry tough skin to live on land,
this is an adaptation
• Reptiles have amniotic eggs that has a
membrane layer inside to hold liquid
• Reptiles have kidneys that are used to filter
wastes from the blood
Reptiles
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Most reptiles today are either lizards or snakes
Both have overlapping scales
Both also have to shed their skin
Difference is lizards have legs, 2 lungs, and
moveable eyelids
• Alligators and Crocodiles are the biggest
reptiles on Earth today.
Reptiles
• Alligators have rounded snouts, crocodiles
have pointed snouts
• Both are large carnivores that care for their
young
• Mothers carry their young after they hatch to
the water
• Most hunt at night
– Rarely attack humans
Reptiles
• Turtles live in the ocean, in fresh water and on
land
• Turtles that live on land are called “tortoises”
• A turtle is a reptile that is covered by a
protective shell that includes the ribs and
backbone
• Turtles have large scales and can draw their
bodies into their shells
Reptiles
• Turtles lack teeth but have razor sharp beaks
to tear food
• Leatherbacks have tough skin to allow it to eat
jellyfish
• The Galapagos tortoise feeds on cacti after
scrapping off the spine
•Section 6
•Birds and Mammals
Characteristics of Birds
• Birds are endothermic vertebrates that lay eggs
and have feathers and a four chambered heart
• Birds also have scales on their feet and legs
• Most birds are also capable of flight
• A birds body is adapted for flight
• Of all animals, only birds have feathers
• Birds have different types of feathers, for
different functions
Characteristics of Birds
• The large feathers that give birds their shape
are called contour feathers
• Contour feathers also help the bird to steer
during flight and to balance
• Down feathers are specialized to trap heat
– These feathers grow at the base of the contour
feathers, close to the skin
• Another adaptation for flight is a birds bones
are nearly hollow
Characteristics of Birds
• Birds have no teeth, they have bills
• Each bird has a different bill shape to better
help it feed
• Many birds store food in an internal storage
tank called a crop
• Food then leaves the crop and goes to the 1st
part of the stomach
• Here the food is bathed in chemicals to break
it down
Characteristics of Birds
• After the 1st stomach part, which is thin, it
moves to the 2nd stomach which is thick
walled and muscular, called the gizzard, which
squeezes and grinds the food.
• Birds are endothermic, so they need lots of
energy to keep conditions stable and for use in
muscles
Characteristics of Birds
• Birds eat ¼ of their body weight in food
• Like reptiles, birds have internal fertilization
and lay eggs
• Female birds lay the eggs in a nest made by 1
or both parents
• In order to develop eggs need a temp. close to
the parents
– That is why parent birds sit on the eggs to keep
them warm
Characteristics of Birds
• In some species, only 1 parent will incubate
the egg
• When the egg is ready to hatch, the chick
pecks its way out of the egg shell
• Most parents protect and feed the chick until
the chick is ready to fly
Birds in the Environment
• With 10,000 species, birds are the most
diverse land dwelling vertebrates
• Birds are adapted for living in diverse
environments, we can see these adaptations
in their legs, claws and bills
• Birds play a big part in the environment, they
help with pollination, hunt pests, and eat
insects
Characteristics of Mammals
• Mammals are endothermic vertebrates with 4
chambered hearts and skin covered by fur or
hair
• The young of most mammals are born alive,
and the young is fed milk produced in the
mother’s body
• Animals teeth are adapted for chewing their
food and breaking it down so its easier to
digest
Characteristics of Mammals
• Mammals usually have 4 different teeth
shapes
– Flat edged to bite off parts of food
– Canines that are sharp and pointy to stab food
– Premolars and molars are used to grind food
• Mammals breathe in and out b/c of combined
action of rib muscles and a large muscle called
a diaphragm
Characteristics of Mammals
• Mammals are endothermic and able to keep a
constant body temp.
• One adaption is growing hair of fur on the
body
– Another is fat
• Mammals move in many ways
– Some run on 2 or 4 legs, some hop, some swing by
their arms, some fly and some swim
Characteristics of Mammals
• Brains of mammals are well developed, brains
are large based on proportion
• Development leads to sonar for bats and
dolphins, large eyes for tarsiers, and great
hearing and eyesight for cats and dogs
Diversity of Mammals
• The 3 main groups of mammals are
monotremes, marsupials, and placental
mammals.
– Duck-billed platypus, panda, and kangaroo
• Mammals that lay eggs are monotremes
– Only 3 species, 2 species of spiny anteaters, and
the duck-billed platypus
• Females lay eggs in their bellies, then the
young drink milk from a pouch
Diversity of Mammals
• Marsupials are mammals whose young are
born in early development, then develop in
the mothers pouch
• Most mammals are placental, including
humans
• Placental mammals develop inside the
mother’s body until its body systems can
function independently