Transcript Section 2: Energy Flow in Ecosystems

Introduction to Animals
CH 26:
Introduction to Animals
Sec 1 and Sec 2
Section 2
Introduction to Animals
Section 2
General Features of Animals
• Animals are multicellular, heterotrophic organisms with
cells that lack cell walls.
• Humans depend on other animals for food,
companionship, and to pollinate crops.
• Most animals move to get food. But filter eaters, such as
sponges and corals, catch particles of food that drift by in
the water.
Introduction to Animals
Section 2
Kinds of Animals
• Animals are often grouped as invertebrates or
vertebrates.
• Vertebrates make up only a subgroup of one phylum—
Chordata.
• Most animals are invertebrates.
Introduction to Animals
Section 2
Kinds of Animals, continued
Vertebrates
• Vertebrates have a cranium and an internal skeleton
composed of bone or cartilage.
• Vertebrates are chordates that have a backbone.
• The backbone supports and protects a dorsal nerve cord
and provides a site for muscle attachment.
• Pg 625
Introduction to Animals
Section 2
CH26 Sec 2: Animal Body Systems
Introduction to Animals
Section 2
Key Ideas
• Why is an animal's skeleton important?
• What are the functions of the digestive and excretory
systems?
• What is the function of the nervous system?
• Why are the respiratory and circulatory systems
important?
• What are two reproductive strategies of animals?
Introduction to Animals
Section 2
Support
• An animal's skeleton provides support for the animal's
body and location for muscle attachment.
• Many soft-bodied invertebrates, such as jellyfish, have a
hydrostatic skeleton
– which is a water-filled cavity that is under pressure.
• An exoskeleton is a rigid external skeleton that
encases the body of an animal.
• An endoskeleton is an internal skeleton made of bone
and cartilage.
Introduction to Animals
Section 2
Digestive and Excretory Systems
• The digestive system is responsible for extracting
energy and nutrients from an animal's food.
• The excretory system removes waste products from the
animal's body.
Introduction to Animals
Digestive System
• A gastrovascular cavity
is a digestive cavity with
only one cavity.
• The hydra has a
gastrovascular cavity.
Section 2
Introduction to Animals
Section 2
Digestive System, continued
• In a digestive tract, food moves from one opening, the
mouth, to a second, the anus.
• Digestive tracts allow for specialization and more
efficient digestion.
Introduction to Animals
Section 2
Digestive and Excretory Systems,
continued
Excretory System
• The removal of wastes produced by cellular metabolism.
• Simple aquatic invertebrates and some fishes excrete
ammonia through their skin or gills.
• Terrestrial animals need to minimize water loss.
Introduction to Animals
Section 2
Nervous System
• Carries information about the environment through the
body and coordinates responses and behaviors.
– Nerve net
– Ganglia
– Brain
Introduction to Animals
Hydra Nervous System
Section 2
Introduction to Animals
Flatworm Nervous System
Section 2
Introduction to Animals
Grasshopper Nervous System
Section 2
Introduction to Animals
Section 2
Respiratory and Circulatory Systems
• The respiratory system is responsible for exchanging
oxygen and carbon dioxide between the body and the
environment.
– Gills
– Lungs
• The circulatory system transports gases, nutrients, and
other substances within the body.
Introduction to Animals
Section 2
Circulatory System
• Open circulatory system
– a heart pumps fluid containing oxygen and nutrients through
vessels into the body cavity.
– The fluid provides oxygen and nutrients as it washes across the
tissues.
• Closed circulatory system
– the blood is pumped through the body within vessels
– is never in direct contact with the body's tissues.
Introduction to Animals
Section 2
Open and Closed Circulatory Systems
Introduction to Animals
Section 2
Reproduction
• Asexual reproduction occurs when an individual
produces exact copies of itself and gametes are not
exchanged.
– Budding
– Parthenogenesis
– Fragmentation
• Sexual reproduction, a new individual is formed by the
union of a male and female gametes.
• Some species can reproduce either asexually or sexually.