Animals Chapter 2

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Animals Chapter 2

• Sponges, Cnidarians, and Worms
• Sections 1 and 2

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Definitions

• Nerves carry signals throughout the body
• Ganglia groups of nerves bundled together.
  Animals can have a brain and ganglia or just have
  ganglia depending on how advanced the animal is
• Gut pouch lined with digestive enzymes
• Coelom cavity that allows organs such as the
  gut, heart etc to work without interference from
  body movement

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Coelom
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Ganglion
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Symmetry
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Sponges

• Phylum Porifera
• 1st animals on earth

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Phylum Porifera

• Simplest of all animals
• Asymmetrical
• No head, nervous system, gut or coelom
• Spicules are needle-like splinters that make up
  the skeleton
• If cells are separated, they can come back
  together
• Both asexual and sexual reproduction

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Sponge Anatomy

• Pores - used to pump water into sponge
• Collar Cells filters particles of food from
  water and digests them
• Osculum hole at the top of the sponge

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Anatomy of a Sponge
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Cnidarians

• Jellyfish
• Hydra
• Sea anenome
• corals

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Phylum Cnidaria

• Radial symmetry
• Complex tissues
• Gut
• Nerve net and nerve ring in medusa form
• If cells get separated, they come back together
• Tentacles covered with nematocysts
• Nematocysts stinging cells
• Sexual and asexual reproduction

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Body Forms

• Medusa free swimming, mushroom shaped
• Polyp vase shaped, attached to a surface
• Most spend life as polyps but some are born
  polyps and turn into medusas

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Flatworms - Platyhelmenthes

• Planaria
• Flukes
• Tapeworms

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Characteristics

• Bilateral symmetry
• Nervous system
• Ganglia acts as a brain
• Sensory lobes to detect light and food
• Planaria have a gut
• Fluke and tapeworms are parasites and have no gut

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Reproduction of Fluke
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Reproduction of Tapeworms

• Sexual
• Can go from uncooked meat to human

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Roundworms - Nematoda
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Roundworm

• Pseudocoelom tube within a tube
• Bilateral symmetry
• Can pick up through the soles of feet, through
  dirty hands, through some foods

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Segmented Worms - Annelida

• Includes earthworms, bristle worms and leeches
• Can live in water or on land

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Earthworms, Bristle Worms, Leeches

• Earthworms aerate soil (makes tunnels) to allow
  water and air in, break down organic matter into
  elements that can be used
• Bristle Worms all live in water
• Leeches can be scavengers, predators or
  parasites, and can be used in medicine

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Next

• Earthworm dissection
• Earthworm questions powerpoint

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Mollusks

• Phylum Mollusca
• Soft bodied usually with a shell or shells
• Three classes
• Gastropods snails and slugs
• Bivalves 2 shells- clams, mussels, etc.
• Cephalopods squid and octopus

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Similarities Between Mollusks
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Feeding

• Different depending on species
• Gastropods have a radula which is like a really
  rough tongue and scraps algae, leaves etc.
• Bivalves filter feed
• Cephalopods use tentacles to grab prey

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Circulatory System

• Most mollusks have an open system
• Open system - A simple heart pumps blood into
  sinuses
• Cephalopods have a closed system
• Closed system blood is circulated through a
  closed loop

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Brains

• Most mollusks have ganglia spread throughout
  their body
• Cephalopods have a brain where all of the ganglia
  are connected

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Next

• Squid Dissection