Mollusks have a well-developed circulatory Mollusks have a well-developed circulatory system that includes a three-chambered heart.system that includes a three-chambered heart.

Circulation in mollusksCirculation in mollusks

Heart

In most mollusks, the heart pumps blood In most mollusks, the heart pumps blood through an open circulatory system.through an open circulatory system.

In an In an open circulatory systemopen circulatory system, the blood , the blood moves through vessels and into open spaces moves through vessels and into open spaces around the body organs.around the body organs.

Circulation in mollusksCirculation in mollusks

Some mollusks, such as octopuses, move Some mollusks, such as octopuses, move nutrients and oxygen through a closed nutrients and oxygen through a closed circulatory system.circulatory system.

In a In a closed circulatory systemclosed circulatory system, blood moves , blood moves through the body enclosed entirely in a series through the body enclosed entirely in a series of blood vessels.of blood vessels.

Circulation in mollusksCirculation in mollusks

Most mollusks have respiratory structures Most mollusks have respiratory structures called gills.called gills.

Respiration in mollusksRespiration in mollusks

Gills are specialized parts of the mantle that Gills are specialized parts of the mantle that consist of a system of filamentous projections consist of a system of filamentous projections that contain a rich supply of blood for the that contain a rich supply of blood for the transport for gases.transport for gases.

The water vascular systemThe water vascular system

The The water vascular systemwater vascular system is a hydraulic is a hydraulic system that operates under water pressure.system that operates under water pressure.

Water enters and leaves the water vascular Water enters and leaves the water vascular system of a sea star through the system of a sea star through the madreporite madreporite (mah druh POHR ite),(mah druh POHR ite), a sievelike, disk-shaped a sievelike, disk-shaped opening on the upper surface of the opening on the upper surface of the echinoderm’s body.echinoderm’s body.

The water vascular systemThe water vascular system The underside of a sea star has tube feet that The underside of a sea star has tube feet that

run along a groove on the underside of each run along a groove on the underside of each ray.ray.

The water vascular systemThe water vascular system

Tube feetTube feet are hollow, thin-walled tubes that are hollow, thin-walled tubes that end in a suction cup.end in a suction cup.

Tube feet look somewhat like miniature Tube feet look somewhat like miniature droppers.droppers.

The round, muscular structure called the The round, muscular structure called the ampulla (AM pew lah)ampulla (AM pew lah) works something like works something like the bulb of a dropper.the bulb of a dropper.

The water vascular systemThe water vascular system Each tube foot Each tube foot

works independently works independently of the others, and of the others, and the animal moves the animal moves along slowly by along slowly by alternately pushing alternately pushing out and pulling in its out and pulling in its tube feet.tube feet. Ampullae

The water vascular systemThe water vascular system

Tube feet also function in gas exchange and Tube feet also function in gas exchange and excretion. Gases are exchanged and wastes excretion. Gases are exchanged and wastes are eliminated by diffusion through the thin are eliminated by diffusion through the thin walls of the tube feet.walls of the tube feet.

This large oxygen demand is needed to This large oxygen demand is needed to sustain the high levels of metabolism sustain the high levels of metabolism required for rapid movements.required for rapid movements.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange Arthropods have efficient respiratory Arthropods have efficient respiratory

structures that ensure rapid oxygen structures that ensure rapid oxygen delivery to cells.delivery to cells.

Three types of Three types of respiratory respiratory structures structures have evolved have evolved in arthropods: in arthropods: gills, tracheal gills, tracheal tubes, and tubes, and book lungs.book lungs.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Aquatic Aquatic arthropods arthropods exchange gases exchange gases through gills, through gills, which extract which extract oxygen from oxygen from water and water and release carbon release carbon dioxide into the dioxide into the water.water.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Land arthropods have either a system of tracheal Land arthropods have either a system of tracheal tubes or book lungs.tubes or book lungs.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Most insects have Most insects have tracheal tubestracheal tubes, branching , branching networks of hollow air passages that carry air networks of hollow air passages that carry air throughout the body.throughout the body.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Air enters and leaves the tracheal tubes Air enters and leaves the tracheal tubes through openings on the thorax and through openings on the thorax and abdomen called abdomen called spiraclesspiracles..

Muscle activity helps pump the air through Muscle activity helps pump the air through the tracheal tubes.the tracheal tubes.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Most spiders and their relatives have Most spiders and their relatives have book lungsbook lungs, , air-filled chambers that contain leaflike plates.air-filled chambers that contain leaflike plates.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

The stacked plates of a book lung are arranged The stacked plates of a book lung are arranged like pages of a book.like pages of a book.

Arthropods have efficient gas exchangeArthropods have efficient gas exchange

Fishes have gills made up of feathery gill Fishes have gills made up of feathery gill filaments that contain tiny blood vessels.filaments that contain tiny blood vessels.

Fishes breathe using gillsFishes breathe using gills

Gill FilamentsGill Filaments

As a fish takes water in As a fish takes water in through its mouth, through its mouth, water passes over the water passes over the gills and then out gills and then out through slits at the side through slits at the side of the fish.of the fish.

Fishes breathe using gillsFishes breathe using gills

Gill FilamentsGill Filaments

Capillary networksCapillary networksin filamentin filament GillGill

filamentsfilaments

WaterWater

WaterWater

ArteryArtery

VeinVein

Fishes breathe using gillsFishes breathe using gills

Oxygen and carbon Oxygen and carbon dioxide are exchanged dioxide are exchanged through the capillaries in through the capillaries in the gill filaments.the gill filaments. Gill FilamentsGill Filaments

GillGillfilamentsfilaments

WaterWater

WaterWater

ArteryArtery

VeinVein

Capillary networksCapillary networksin filamentin filament

Fishes have two-chambered heartsFishes have two-chambered hearts

HeartHeart

GillsGills

AortaAorta

Capillary Capillary networknetwork

Flight requires energyFlight requires energy

Flight requires high levels of energy.Flight requires high levels of energy.

Several factors are involved in maintaining these Several factors are involved in maintaining these high energy levels.high energy levels.

Flight requires energyFlight requires energy First, a bird’s four-First, a bird’s four-

chambered, rapidly chambered, rapidly beating heart moves beating heart moves oxygenated blood quickly oxygenated blood quickly throughout the body.throughout the body.

This efficient circulation This efficient circulation supplies cells with the supplies cells with the oxygen needed to oxygen needed to produce energy.produce energy.

Flight requires energyFlight requires energy Second, a bird’s respiratory system supplies Second, a bird’s respiratory system supplies

oxygenated air to the lungs when it inhales as oxygenated air to the lungs when it inhales as well as when it exhales.well as when it exhales.

A bird’s respiratory system consists of lungs A bird’s respiratory system consists of lungs and anterior and posterior air sacs.and anterior and posterior air sacs.

Flight requires energy

Flight requires energy

During inhalation, During inhalation, oxygenated air oxygenated air passes through the passes through the trachea and into trachea and into the lungs, where the lungs, where gas exchange gas exchange occurs.occurs.

Trachea

Anterior air sacs

Lung

Posterior air sacs

Anterior air sacs

Key: Breathing cycles

Cycle 1Inhalation 1

Exhalation 2Inhalation 1

Cycle 2

Exhalation 2

Most of the air, Most of the air, however, passes however, passes directly into the directly into the posterior air sacs.posterior air sacs.

Trachea

Anterior air sacs

Lung

Posterior air sacs

Anterior air sacs

Key: Breathing cycles

Cycle 1Inhalation 1

Exhalation 2Inhalation 1

Cycle 2

Exhalation 2

Flight requires energy

Flight requires energy

Trachea

Anterior air sacs

Lung

Posterior air sacs

Anterior air sacs

Key: Breathing cycles

Cycle 1Inhalation 1

Exhalation 2Inhalation 1

Cycle 2

Exhalation 2

When a bird exhales When a bird exhales deoxygenated air deoxygenated air from the lungs, from the lungs, oxygenated air oxygenated air returns to the lungs returns to the lungs from the posterior air from the posterior air sacs.sacs.

Flight requires energy

Flight requires energy

At the next At the next inhalation, inhalation, deoxygenated deoxygenated air in the lungs air in the lungs passes into the passes into the anterior air anterior air sacs.sacs.

Trachea

Anterior air sacs

Lung

Posterior air sacs

Anterior air sacs

Key: Breathing cycles

Cycle 1Inhalation 1

Exhalation 2Inhalation 1

Cycle 2

Exhalation 2

Flight requires energy

Flight requires energy

Finally, at the next Finally, at the next exhalation, air exhalation, air passes from the passes from the anterior air sacs out anterior air sacs out of the trachea. of the trachea. Thus, air follows a Thus, air follows a one-way path in a one-way path in a bird.bird.

Trachea

Anterior air sacs

Lung

Posterior air sacs

Anterior air sacs

Key: Breathing cycles

Cycle 1Inhalation 1

Exhalation 2Inhalation 1

Cycle 2

Exhalation 2

Flight requires energy

Flight requires energy

• The laborious walking of early amphibians required a great deal of energy from food and large amounts of oxygen for aerobic respiration.

Walking requires more energyWalking requires more energy

• The evolution of the three-chambered heart in amphibians ensured that cells received the proper amount of oxygen.

• In the three-chambered heart of amphibians, one chamber receives oxygen-rich blood from the lungs and skin, and another chamber receives oxygen-poor blood from the body tissues.

Walking requires more energyWalking requires more energy

• Blood from both chambers then moves to the third chamber, which pumps oxygen-rich blood to body tissues and oxygen-poor

blood back to the lungs and skin so it can pick up more oxygen.

Walking requires more energyWalking requires more energy

• Because the skin of an amphibian must stay moist to exchange gases, most amphibians are limited to life on the water’s edge or other moist areas.

Walking requires more energyWalking requires more energy

Most reptiles have three-chambered hearts.Most reptiles have three-chambered hearts.

Some reptiles have four-chambered heartsSome reptiles have four-chambered hearts

Some reptiles, notably the crocodilians, have a Some reptiles, notably the crocodilians, have a four-chambered heart that completely four-chambered heart that completely separates the supply of blood with oxygen from separates the supply of blood with oxygen from blood without oxygen.blood without oxygen.

This separation is an adaptation that supports This separation is an adaptation that supports a higher level of energy use required by land a higher level of energy use required by land animals.animals.

All reptiles have All reptiles have internal fertilization. internal fertilization. In most cases, the In most cases, the eggs are laid after eggs are laid after fertilization and fertilization and embryos develop after embryos develop after eggs are laid.eggs are laid.

Some reptiles have four-chambered heartsSome reptiles have four-chambered hearts

Most reptiles provide Most reptiles provide no care for no care for hatchlings, but hatchlings, but female crocodiles female crocodiles have been observed have been observed guarding their nests guarding their nests from predators.from predators.

Some reptiles have four-chambered heartsSome reptiles have four-chambered hearts

Respiration and circulation in mammalsRespiration and circulation in mammals The mammals’ diaphragm helps expand the The mammals’ diaphragm helps expand the

chest cavity to aid the flow of oxygen into their chest cavity to aid the flow of oxygen into their lungs.lungs.

Position of diaphragm when exhaling

Position of diaphragm when inhaling

Position of ribs when exhaling

Lungs when

exhaling

Position of ribs when inhaling

Lungs when

inhaling

A A diaphragmdiaphragm is the sheet of muscle located is the sheet of muscle located beneath the lungs that separates the chest beneath the lungs that separates the chest cavity from the abdominal cavity, where other cavity from the abdominal cavity, where other organs are located.organs are located.

Position of diaphragm when exhaling

Position of diaphragm when inhaling

Respiration and circulation in mammalsRespiration and circulation in mammals

Mammals have Mammals have four-chambered four-chambered hearts in which hearts in which oxygenated oxygenated blood is kept blood is kept entirely separate entirely separate from from deoxygenated deoxygenated blood.blood.

Right atrium

Right ventricle

Left atrium

Left ventricle

Respiration and circulation in mammalsRespiration and circulation in mammals

Circulation also removes waste products Circulation also removes waste products from cells and helps regulate body from cells and helps regulate body temperature.temperature.

Blood helps keep a constant cellular Blood helps keep a constant cellular environment, which maintains homeostasis.environment, which maintains homeostasis.

Respiration and circulation in mammalsRespiration and circulation in mammals

1)Compare and contrast gills and lungs1)Compare and contrast gills and lungs

2) What components do all gas exchange 2) What components do all gas exchange systems have?systems have?

3) Define tracheal tubes3) Define tracheal tubes

4) Why do some animals have simple system 4) Why do some animals have simple system and some complexand some complex

5)Compare and contrast open and closed 5)Compare and contrast open and closed circulatory system circulatory system

6) List all of the possible ways animals can 6) List all of the possible ways animals can capture Ocapture O2 2 from the air from the air

7) What factors shape the type and complexity 7) What factors shape the type and complexity of the system of the system