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Animal Body Systems. Objectives…(At the end of this lecture you should be able to): Summarize the functions of the digestive, respiratory, circulatory, nervous, skeletal and excretory systems. Compare a gastro vascular cavity with a one-way digestive system.
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Animal Body Systems Objectives…(At the end of this lecture you should be able to): Summarize the functions of the digestive, respiratory, circulatory, nervous, skeletal and excretory systems. Compare a gastro vascular cavity with a one-way digestive system. Differentiate open from closed circulatory systems. Distinguish asexual from sexual reproduction.
Body Systems are specialized to carry out different tasks • Simple animals like sponges carry out the many tasks of living with little specialization in the cells of their body. • More complex animals have evolved tissues and organs that are specialized to perform specific functions.
Body Systems are specialized to carry out different tasks • Seven important functions of these tissues and organs are : • Digestion • Respiration • Circulation • Conduction of nerve impulses • Support • Excretion • Reproduction
Digestion • Purpose: Obtain energy & nutrients • Sponges digest their food with their body cells • Simple animals, such as flatworms, have a gastro vascular cavity: a digestive cavity with only one opening. • More complex animals, like us, have a digestive tract with two openings: mouth and anus.
Respiration • Purpose: Exchange oxygen and carbon dioxide gases • Can only take place across a moist surface. • In simple animals like jellyfish gasses are exchanged directly with their environment through diffusion. • More complex animals have specialized respiratory structures like gills or lungs.
Circulation • Purpose: Transport oxygen and nutrients to the other parts of the body • There are 2 types of circulatory systems: • Open: heart pumps fluid containing oxygen through a series of vessels & is dumped into the body cavity. • Closed: heart pumps blood through a system of blood vessels. The blood stays in the vessels the whole time. OPEN: CLOSED:
Conduction of nerve impulses • Purpose: Coordinate the activities in an animal’s body and allow animal to sense and respond to environment. • Simple animals, like hydra, have little coordination among their nerve cells. • Complex animals, like grasshoppers, have nerve cords/ganglia & a brain.
Support: Skeletal • Purpose: Provide a framework that supports the body. • Many soft-bodied invertebrates have a hydrostatic skeleton made of water like a filled water balloon. • Other invertebrates, such as insects & crabs, have an exoskeleton: a rigid external skeleton. • Complex animals, like dogs, have an endoskeleton: hard material such as bone embedded within the animal.
Excretion • Purpose: Removal of wastes from cellular metabolism (CO2, ammonia, etc.) • Simple aquatic invertebrates & some fishes pass it through their skin/gills by diffusion. • More complex animals have specialized excretory structures like kidneys.
Reproduction • Purpose: produce offspring to ensure that the species survives • Two types of reproduction: • Asexual: does not involve fusion of two gametes. • EX: A sponge can reproduce by fragmenting its body. Sea anemones pull apart into 2 individuals • Sexual: a new individual is formed by the union of a male and female gamete. • EX: egg + sperm = fertilization = blastula
Pregnant sea horse fathers give birth. A female sea horse inserts her eggs into a pouch on the male’s abdomen, where they are fertilized. The male incubates the eggs until they are fully developed and then gives birth to tiny sea horses. Fun & Funky Fact: Sea “horse” reproduction
Fertilization • There are two types of fertilization: • External: occurs outside the body • EX: Most aquatic animals simply release the male and female gametes near one another in the water, where fertilization occurs…..think opening scene of Finding Nemo….they were outside the mom. • Internal: occurs inside the females body • EX: Animals that live on land don’t have water so the gametes would dry out. Internal fertilization allows it to take place in a moist environment.
Objectives… • (At the end of this lecture you should be able to): • Summarize the functions of the digestive, respiratory, circulatory, nervous, skeletal and excretory systems. • Compare a gastro vascular cavity with a one-way digestive system. • Differentiate open from closed circulatory systems. • Distinguish asexual from sexual reproduction.
Quick Test • Which two body systems in most animals are involved in taking up oxygen from the environment and transporting oxygen to body cells? • Digestive & Respiratory • Respiratory & Circulatory • Circulatory & Nervous • Nervous & Excretory