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. CLOSED: OPEN:

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 (CO 2, 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

Is this sexual or asexual reproduction ?

Fun & Funky Fact: Sea “horse” reproduction  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.

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.Summarize the functions of the digestive, respiratory, circulatory, nervous, skeletal and excretory systems. Compare a gastro vascular cavity with a one- way digestive system.Compare a gastro vascular cavity with a one- way digestive system. Differentiate open from closed circulatory systems.Differentiate open from closed circulatory systems. Distinguish asexual from sexual reproduction.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? a)Digestive & Respiratory b)Respiratory & Circulatory c)Circulatory & Nervous d)Nervous & Excretory

The correct answer is: B

Today’s classwork:  Directed Reading Worksheet (page 5)  Use your notes &/or Chapter 27, Section 2 to complete this in full sentences.  This is an independent assignment &  Is due before you leave  Is due before you leave