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

Flat Worms

Round Worms

Segmented Worms

Long Flat body

Long Round body

Long round body made up of segments

Food absorbed through body wall, or enters and exits same opening

Food enters at head, exits at tail

Food enters at head, exits at tail

Simplest kind of animal with bilateral symmetry

Among most numerous of all types of animals

May be more closely related to arthropods than worms

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 propulsionThey squeeze out a current of water out of the

space surrounded by the mantle.

Section 4Arthropods 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

• 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

• 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