What Is a Chordate? Members of the phylum Chordata are ...taubitz.weebly.com/.../0/4/...amphibia,_reptillia,_aves,_and_mammalia.pdf · Chemical Controls. Title: Biology Author: Scott

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Copyright Pearson Prentice Hall

What Is a Chordate?

Members of the phylum Chordata are called chordates.

A chordate is an animal that has, for at least some stage of its life, a dorsal, hollow nerve cord; a notochord; pharyngeal pouches; and a tail that extends beyond the anus.

Muscle segments

Mouth

Pharyngeal pouches

Anus Tail

What Is a Chordate?

Hollow nerve cord

Notochord

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•The notochord is a long supporting rod that runs through the body just below the nerve cord.

•Pharyngeal pouches are paired structures in the throat (pharynx) region.

•The tail can contain bone and muscle and is used for swimming by many aquatic species.

Most Chordates Are Vertebrates

•About 96 percent of all chordate species are vertebrates.

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Most vertebrates have a vertebral column, or

backbone.

In vertebrates, the dorsal, hollow nerve cord is

called the spinal cord.

As a vertebrate embryo develops, the front end of

the spinal cord grows into a brain.

The backbone is made of individual segments

called vertebrae.

In addition to support, vertebrae enclose and

protect the spinal cord.


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Phylogeny of Chordates

Sharks

& their

relatives

Bony

fishes

Amphibians Reptiles Birds

Mammals

Invertebrate ancestor

Jawless

fishesNonvertebrate

chordates


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Nonvertebrate Chordates

The two groups of nonvertebrate

chordates are tunicates and lancelets.

Nonvertebrate Chordates

Similarities in anatomy and embryological

development indicate that vertebrates and

nonvertebrate chordates evolved from a

common ancestor.

Both tunicates and lancelets are soft-bodied

marine organisms.

http://www.youtube.com/watch?v=GUR3sQR9nUY&feature=related

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http://cas.bellarmine.edu/tietjen/Laboratories/Bio Pix 4 U/Image4.gif

http://cas.bellarmine.edu/tietjen/Laboratories/Bio Pix 4 U/Image4.gif

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What Is a Fish?

What Is a Fish?

Fishes are aquatic vertebrates. Most fishes have paired fins, scales, and gills.

Anal fin

Eye

Mouth

Dorsal fin Caudal fin

Operculum

(gill cover) Pelvic fin Pectoral fin

Lateral line Scales

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Form and Function in Fishes


Adaptations to aquatic life include various modes of feeding, specialized structures for gas exchange, and paired fins for locomotion.

Feeding

•Every mode of feeding is seen in fishes.

•A single fish may exhibit several modes of

feeding, depending on the type of food available.

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Food passes through the mouth and esophagus, into

the stomach.

In the stomach, the food is partially broken down.

Mouth

Esophagus

Stomach Pyloric cecum

Liver Pancreas

Intestine

Anus

Gills

Kidney

Brain

Swim bladder

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In many fishes, the food is further processed in

fingerlike pouches called pyloric ceca.

The pyloric ceca secretes digestive enzymes and

absorbs nutrients from the digested food.

The liver and pancreas add enzymes and other

digestive chemicals to the food as it moves through

the digestive tract.

The intestine completes the process of digestion and

nutrient absorption.

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Undigested material is eliminated through the anus.

Respiration

•Most fishes exchange gases using gills located

on either side of the pharynx.

•Fishes use their gills to exchange gases by

pulling oxygen-rich water in through their mouths,

pumping it over their gill filaments, and pushing

oxygen-poor water out through openings in the

sides of the pharynx.

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Body

muscle

circulation

Brain and

head

circulation

Heart Digestive system

circulation

Gills Circulation in a Fish

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Circulation

•Fishes have closed circulatory systems with a heart that pumps blood around the body in a single loop from the heart to the gills, from the gills to the rest of the body, and then back to the heart.

•In most fishes, the heart has four parts:

the sinus venosus

the atrium

the ventricle

the bulbus arteriosis

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Excretion

•Fishes eliminate nitrogenous wastes in the form of ammonia.

•Some wastes diffuse through the gills into the surrounding water.

Others wastes are removed by kidneys.

The kidneys of marine fishes concentrate wastes and return water to the body.

The kidneys of freshwater fishes pump out dilute urine.

Response

•Fishes have well-developed nervous systems organized around a brain.

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The olfactory bulbs are involved with the sense of smell, or olfaction.

In most vertebrates, the cerebrum is responsible for all the voluntary activities of the body.

In fishes, however, the cerebrum primarily processes the sense of smell.

The optic lobes process information from the eyes.

Olfactory

bulb

Cerebrum

Optic lobe

Cerebellum

Medulla

oblongata

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The cerebellum coordinates body movements.

The medulla oblongata controls the functioning of

many internal organs.

Almost all fishes that are active in daylight have

well-developed eyes and color vision.

Many fishes have extraordinary senses of taste and

smell.

Most fishes have ears but may not hear sounds

well.

http://www.youtube.com/watch?v=UfC4u5GCy3I

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Fishes use the lateral line system to sense the motion of other fishes or prey swimming nearby.

Some fishes can detect low levels of electric current.

Many bony fishes have an internal, gas-filled organ called a swim bladder that adjusts their buoyancy.

Movement

•Most fishes move by contracting paired sets of muscles on either side of the backbone.

•A series of S-shaped curves move down the fish’s body.

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•The force and the action of the fins propels the

fish forward.

•The fins of fishes are used to keep on course

and adjust direction.

Reproduction

•The eggs of fishes are fertilized either externally

or internally, depending on the species.

•Fishes whose embryos in the eggs develop and

hatch outside the mother's body are oviparous.

•The embryos of oviparous fishes obtain food

from the yolk in the egg.

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In ovoviviparous species, the eggs stay in the

mother's body after internal fertilization.

Each embryo develops inside its egg, using the yolk

for nourishment.

The young are “born alive” like most mammals.

In viviparous animals, the embryos stay in the

mother's body after internal fertilization.

These embryos obtain the substances they need

from the mother's body (not from material in an egg).

The young of viviparous species are “born alive.”

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Groups of Fishes

All living fishes can be classified into three groups: jawless fishes, cartilaginous fishes, and bony fishes.

Jawless Fishes - class Agnatha

•Jawless fishes have no true teeth or jaws.

•Their skeletons are made of fibers and cartilage.

•They lack vertebrae, and keep their notochords as

adults.

•Modern jawless fishes are divided into two classes:

lampreys and hagfishes.

Groups of Fishes

Lamprey

http://www.youtube.com/watch?v=IgrOK_831DY&feature=related

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Sharks and Their Relatives

•The class Chondrichthyes contains sharks, rays,

skates, sawfishes, and chimaeras.

•The skeletons of these fishes are built entirely of

cartilage.

•Many sharks have thousands of teeth arranged

in several rows.

•Most species of sharks do not attack people.

Groups of Fishes

http://www.youtube.com/watch?v=FqtluWUMg8w

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Some skates and rays feed on bottom-dwelling

invertebrates.

The largest rays eat floating plankton.

Skates and rays glide through the sea with their

large, winglike pectoral fins.

Many skates and rays cover themselves with sand

and rest on the ocean floor.

Groups of Fishes

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Bony Fishes

•Class Osteichthyes.

•Their skeletons are made of bone.

•Almost all living bony fishes are ray-finned

fishes.

•“Ray-finned” refers to the slender bony spines, or

rays, that are connected by a thin layer of skin to

form the fins.

Groups of Fishes

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Only seven living species of bony fishes are not classified as ray-finned fishes.

These are the lobe-finned fishes, a subclass that includes lungfishes and the coelacanth.

The fleshy fins of lobe-finned fishes have support bones.

Some of these bones are jointed. Some fishes spend most of their lives in the ocean but migrate to fresh water to breed. These fish are called anadromous.

Ex) Salmon

Groups of Fishes

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30-3 Amphibians

What Is an Amphibian?

An amphibian is a vertebrate that, with some exceptions:

•lives in water as a larva and on land as an

adult

•breathes with lungs as an adult

•has moist skin that contains mucous glands

•lacks scales and claws

Class - Amphibia

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Evolution of Amphibians


•The first amphibians appeared in the late

Devonian Period, about 360 million years ago.

•The transition from water to land required that

the terrestrial vertebrates had to:

breathe air,

protect themselves and their eggs from

drying out, and

support themselves against the pull of

gravity.

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Early amphibians evolved several adaptations that helped them live at least part of their lives out of water.

Bones in the limbs and limb girdles of amphibians became stronger, permitting more efficient movement.

Lungs and breathing tubes enabled amphibians to

breathe air.

The sternum formed a bony shield to support and protect internal organs, especially the lungs.

In many adult amphibians, the internal surfaces of the lungs are richly supplied with blood vessels and folds that increase surface area.

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Form and Function in Amphibians


•The class Amphibia is relatively small and diverse.

Feeding

•Tadpoles are typically filter feeders or herbivores that graze on algae.

•Their intestines help break down hard-to-digest plant material and are usually filled with food.

•The feeding apparatus and digestive tract of adults are meat-eating structures.

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In a frog’s digestive system, food slides down the esophagus into the stomach.

The breakdown of food begins in the stomach and continues in the small intestine.

The liver, pancreas, and gallbladder secrete substances that aid in digestion.

Stomach

Esophagus Mouth

Small

intestine

GallbladderLiver

Pancreas

Cloaca

Large

intestine

(colon)

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At the end of the large intestine is a muscular

cavity called the cloaca, through which digestive

wastes, urine, and eggs or sperm leave the body.

Respiration

•In most larval amphibians, gas exchange

occurs through the skin and the gills.

•Adult amphibians typically respire using lungs,

but some gas exchange occurs through the skin

and the lining of the mouth.

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Circulation

•In frogs and other adult amphibians, the

circulatory system forms a double loop.

•The first loop carries oxygen-poor blood from the

heart to the lungs and skin, and takes oxygen-rich

blood from the lungs and skin back to the heart.

•The second loop transports oxygen-rich blood

from the heart to the rest of the body, and carries

oxygen-poor blood from the body back to the

heart.

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The amphibian heart has three separate chambers:

•left atrium

•right atrium

•ventricle

From

Body

From

Lungs

To body,

lungs and

skin

To body,

lungs

and skin

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Excretion

•Amphibians have kidneys that filter wastes from

the blood.

•Urine travels through tubes called ureters into the

cloaca.

•Urine is then passed directly to the outside, or

temporarily stored in a small urinary bladder just

above the cloaca.

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Reproduction

•In most species of amphibians, the female lays

eggs in water, then the male fertilizes them

externally.

•In a few species, including most salamanders,

eggs are fertilized internally.

•After fertilization, frog eggs are encased in a

sticky, transparent jelly.

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Movement

•Amphibian larvae move by wiggling their bodies and using a flattened tail for propulsion.

•Adult salamanders walk or run.

•Frogs and toads, have well-developed hind limbs that enable them to jump long distances.

Response

•Amphibians have well-developed nervous and sensory systems.

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•An amphibian's eyes are protected from damage

and kept moist by a transparent nictitating

membrane.

•This membrane is located inside the regular

eyelid and can be closed over the eye.

•Amphibians hear through tympanic

membranes, or eardrums, located on each side

of the head.

•Many amphibian larvae and adults have lateral

line systems that detect water movement.

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Groups of Amphibians

Groups of Amphibians

The three groups of amphibians alive today are:

•Salamanders

•frogs and toads

•caecilians

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Class Reptile

What Is a Reptile?

A reptile is a vertebrate that has dry, scaly skin, lungs, and terrestrial eggs with several membranes.

These characteristics enable reptiles to live their entire lives out of water.

Scaly, dry skin prevents the loss of body water in dry environments – must be shed as it grows.

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Evolution of Reptiles

Evolution of Reptiles

Reptiles were the first vertebrates that were not

dependent on water for reproduction.

The first reptile fossil dates back to the

Carboniferous Period.

Form and Function in Reptiles

Tough, scaly skin and the ability to control body

temperature are two adaptations to terrestrial life.

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Adaptations that have contributed to the success of reptiles on land are:

• well-developed lungs

• a double-loop circulatory system

• a water-conserving excretory system

• strong limbs

• internal fertilization

• shelled, terrestrial eggs

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Body Temperature Control

Reptiles are ectotherms.

Ectotherms are animals that rely on behavior to control body temperature.

To warm up, they bask in the sun or stay under water at night.

To cool down, they move to the shade or take shelter in underground burrows.

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Feeding

Reptiles eat a wide range of foods.

Respiration

Reptile lungs are spongy, allowing for a larger area of gas-exchange.

Many reptiles have muscles around the ribs that expand and collapse the chest cavity.

Most reptiles have two lungs, but certain species of snakes have just one lung.

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Circulation

Reptiles have a double-loop circulatory system:

• One loop brings blood to and from the lungs.

• One loop brings blood to and from the rest of the

body.

Reptile hearts have two atria and either one or two

ventricles.

Most reptiles have one ventricle with a partial septum

that separates oxygen-rich and oxygen-poor blood.

Crocodiles and alligators have two atria and two

ventricles.

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Kidney

Liver Heart

Cloaca

Bladder Lung Digestive

tract

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Excretion

Urine is produced in the kidneys.

• In some reptiles, urine flows in tubes directly into a cloaca.

• In others, a bladder stores urine before it is expelled.

Other reptiles convert ammonia into uric acid.

In the cloaca, urine is reduced to crystals of uric acid that form a pasty white solid.

By eliminating solid wastes, a reptile can conserve water.

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Response

Reptilian brains are similar to amphibians.

Their cerebrum and cerebellum are more developed than other parts of the brain.

Reptiles that are active in the day have complex eyes and see color well.

Many snakes also have an extremely good sense of smell.

Most reptiles have sensory organs in the mouth that detect chemicals when reptiles flick their tongues.

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Reptiles have simple ears with an external eardrum and a single bone that conducts sound to the inner ear.

Snakes can also pick up vibrations in the ground through bones in their skulls.

Some snakes can detect the body heat of their prey.

Movement

• Reptiles with legs have large strong limbs.

• Some have legs that are rotated further under the body, enabling them to carry more body weight.

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The legs and feet of many aquatic turtles have

developed into flippers.

Reptiles’ backbones help accomplish much of their

movement.

Reproduction

• Most reptiles are oviparous, laying eggs that

develop outside the mother’s body.

• All reptiles reproduce by internal fertilization, in

which the male deposits sperm inside the

female’s cloaca.

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After fertilization, the female’s reproductive system covers the embryo with several membranes and a leathery shell.

The shell and membranes protect the embryo and prevent the egg from drying out.

This type of egg, an amniotic egg, is one of the most important adaptations to life on land.

An amniotic egg has four membranes—the amnion, the yolk sac, the chorion, and the allantois.

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Groups of Reptiles

Groups of Reptiles

The four surviving groups of reptiles are:

• lizards and snakes

• crocodilians

• turtles and tortoises

• tuataras

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Class “Aves” - Birds

What Is a Bird?

Birds are reptilelike animals that maintain a constant internal body temperature.

Birds have an outer covering of feathers; two legs that are covered with scales and are used for walking or perching; and front limbs modified into wings.

Feathers separate birds from all other living animals.

Feathers are made mostly of protein and develop

from pits in the birds' skin.

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What Is a Bird?

Contour feather: Contour

feathers provide the lifting force

and balance needed for flight.

Down feather: Down

feathers trap air close to the

body and keep the bird warm.

Barbule: The hooks on

each barbule fit together,

holding them flat.

Feathers help birds fly and also keep them warm.

The two main types of feathers are contour and down.

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Evolution of Birds

Evolution of Birds

Paleontologists agree that birds evolved from

extinct reptiles.

• Embryos of birds and reptiles develop within

amniotic eggs.

• Both excrete nitrogenous wastes as uric acid.

• Bones that support the limbs, and other

skeleton parts, are similar in both groups.

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Evolution of Birds

Evolution of Birds

Modern reptiles

Ornithischia

(bird-hipped

dinosaurs)

Saurischia

(lizard-hipped

dinosaurs)

Archaeopteryx

Modern birds

Dinosaurs

Ancestor of

dinosaurs

Reptile ancestor

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Form, Function, and Flight


Birds have a number of adaptations that enable them to fly, including:

highly efficient digestive, respiratory, and

circulatory systems

aerodynamic feathers and wings

strong, lightweight bones

strong chest muscles

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Birds generate their own body heat and are called

endotherms.

Endotherms have a high rate of metabolism.

Metabolism produces heat.

Feathers insulate a bird enough to conserve most

of its metabolic energy, allowing it to keep warm.

Birds need to eat a lot of food to produce the heat

energy they need to maintain metabolism.

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Feeding

Birds’ beaks, or bills, are adapted to the type of

food they eat.

Insect-eating birds have short, fine bills that

pick ants and insects off leaves and branches,

or can catch flying insects.

Seed-eaters have short, thick bills.

Carnivorous birds shred their prey with strong

hooked bills.

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Most birds have a crop - a structure at the

lower end of the esophagus in which food is

stored and moistened.

Birds that eat meat or fish have an

expandable area in which large amounts of

soft food can be stored.

Birds that eat insects or seeds have a

muscular organ called the gizzard that helps

in the mechanical breakdown of food.

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Respiration

Birds have a highly-efficient way of taking in oxygen and eliminating carbon dioxide.

Air enters air sacs.

It flows through the lungs where gas exchange takes place – in one direction.

constantly exposes the lungs to oxygen-rich air.

maintains a high metabolic rate.

provides efficient extraction of oxygen, which enables birds to fly at high altitudes where the air is thin.

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Circulation

Birds have four-chambered hearts and two

circulatory loops.

There is complete separation of oxygen-rich and

oxygen-poor blood.

Oxygen-poor blood from the body is pumped to the

lungs.

Oxygen-rich blood returns from the lungs and is

pumped to the rest of the body.

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Excretion

Excretion in birds is similar to that of most living reptiles.

Nitrogenous wastes are removed from the blood by the kidneys, converted to uric acid, and deposited in the cloaca.

Most of the water is reabsorbed, leaving uric acid crystals in a white, pasty form.

Response

Birds have well-developed sense organs, which are adaptations that enable them to coordinate the movements required for flight.

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Birds’ brains can quickly interpret and respond

to signals.

The cerebrum controls behavior and is large.

The cerebellum coordinates the movement of the

wings and legs; it is larger in birds than in reptiles.

Birds have well-developed eyes which allow them to

see color very well.

Most bird species can hear quite well.

Taste and smell are not well developed in most birds.

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Movement

Some birds, such as ostriches and penguins cannot fly.

Most birds, however, can fly.

The skeletal and muscular systems of flying birds exhibit adaptations that enable flight.

Bones are thinner than those of Reptiles.

Large breast muscles allow for powerful wing control.

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Reproduction

Both male and female reproductive tracts open into

the cloaca.

Mating birds press their cloacas together to

transfer sperm from male to female.

Some male birds have a penis

Bird lay amniotic eggs that have hard outer shells.

Most birds incubate their eggs until the eggs hatch.

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Groups of Birds

Groups of Birds

There are nearly 30 different orders of birds.

The largest order of birds is the passerines, or

perching birds.

Other groups of birds include: pelicans, parrots,

birds of prey, cavity-nesting birds, herons, and

ostriches.

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All mammals have two notable features: hair and mammary glands.

In females, mammary glands produce milk to nourish the young.

In addition to having hair and the ability to nourish their young with milk, all mammals:

breathe air.

have four-chambered hearts.

are endotherms that generate their body heat internally.

Class Mammalia

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Evolution of Mammals

Evolution of Mammals

Mammalian fossils are characterized by a lower jaw with a

large, teeth-bearing bone connected directly to the skull by

a joint, and distinctive features of the limbs and the

backbone.

The first true mammals appeared during the late Triassic

Period, about 220 million years ago.

These mammals were very small and probably nocturnal.

There are now 19 mammal orders (including Artiodactyla,

Carnivora, Chiroptera, Marsupialia, Primates…etc)

- 10 of these orders exist in North America

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Form and Function in

Mammals

Form and Function in Mammals

The mammalian body has adapted in varied ways to a

great many habitats.


Mammals are endotherms.

A high rate of metabolism helps mammals generate body

heat.

Mammals have external body hair that helps them keep

warm.

Subcutaneous fat, which is a layer of fat located beneath

the skin, also helps conserve body heat.

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Mammals

Many mammals have sweat glands that help cool the body.

If its body temperature gets too high, the mammal sweats.

Evaporation of sweat then cools the body.

Some mammals pant to cool down.

These are examples of homeostatic mechanisms

Feeding

Because of its high metabolic rate, a mammal must eat a lot of food to maintain homeostasis.

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Mammals

A mammal’s digestive tract breaks down and

absorbs the type of food that it eats.

Carnivores have a short intestine because enzymes

quickly digest meat.

Herbivores have a longer intestine because tough,

fibrous plant tissues take longer to digest.

Respiration

All mammals use lungs to breathe.

A diaphragm is a large, flat muscle at the bottom

of a mammal’s chest cavity that helps in breathing.

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Mammals

When an animal inhales, chest muscles lift the rib cage up

and out. The diaphragm pulls the chest cavity down.

The combined actions of the chest muscles and diaphragm

increase the volume of the chest cavity.

The increase in volume pulls air into the lungs.

When an animal exhales, chest muscles lower the

rib cage. The diaphragm relaxes, and the volume of

the chest cavity decreases.

Air is then pushed out of the lungs.

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Mammals

Circulation

The mammalian circulatory system has two loops

and a four-chambered heart.

The right side of the heart receives oxygen-poor

blood from the body and pumps it to the lungs.

The left side receives oxygen-rich blood from the

lungs and pumps it to the rest of the body.

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Mammals

Excretion

Kidneys extract nitrogenous wastes from the blood in the form of urea.

Urea, other wastes, and water combine to form urine.

From the kidneys, urine flows to a urinary bladder, where it is stored until it is eliminated.

The kidneys of mammals help maintain homeostasis by filtering urea from the blood, as well as by excreting excess water or retaining needed water – allowing them to live in tough habitats

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Mammals

Response

Mammals have well-developed brains with three

main parts:

• cerebrum—controls thinking and learning

• cerebellum—controls muscular coordination

• medulla oblongata—regulates involuntary body

functions

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Mammals

The cerebrum has a well-developed outer layer

called the cerebral cortex, which is the center of

thinking and other complex behaviors.

Some behaviors, such as reading, are possible only

with the human cerebral cortex.

Mammals other than humans also exhibit complex

behaviors.

Mammals rely on highly developed senses (smell

and hearing) to detect and respond to stimuli from

their external environment.

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Mammals

All mammalian ears have the same basic parts, but

they differ in their ability to detect sound.

Dogs, bats, and dolphins detect sounds at higher

frequencies than humans can.

Elephants detect sounds at much lower

frequencies.

The ability to distinguish colors varies among

species.

Color vision is most useful to animals that are

active during the day.

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Mammals

Chemical Controls

Mammals have endocrine glands that regulate

body activities by releasing hormones.

Hormones are substances produced in one part of

an organism that affect another part of the same

organism.

Hormones are carried by the blood to the organs

that they affect.

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Mammals

Movement

Mammals have backbones that flex vertically and

side to side.

Shoulder and pelvic girdles are streamlined and

flexible, permitting both front and hind limbs to

move in many ways.

Variations in limb bones and muscles permit a

variety of movements.

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Mammals

Reproduction

Mammals reproduce by internal fertilization.

The male deposits sperm inside the reproductive

tract of the female, where fertilization occurs.

All newborn mammals feed on their mother’s milk.

Parental care ensures that young will survive and

reproduce, however the duration and intensity of

parental care varies among different species.

Documents

What Is a Chordate? Members of the phylum Chordata are ...taubitz.weebly.com/.../0/4/...amphibia,_reptillia,_aves,_and_mammalia.pdf · Chemical Controls. Title: Biology Author: Scott