chapter 11: invertebrates copyright © by holt, rinehart and winston. all rights reserved

Chapter 11: INVERTEBRATES

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 11: INVERTEBRATES

What is an animal?An organism’s structure:

Study of how an organism functions:

Levels of Organization:


Functions of Animals

Major functions of Animals:

1.Obtaining food and oxygenWhat do animals eat?How do animals get oxygen?

2.Keeping internal conditions stableExamples:

3.MovingExamples:

4.Reproducing (two types)


Symmetry

A balanced arrangement of body parts that is characteristic of many animals

Bilateral:

Radial:

No symmetry:


Symmetry


http://www.newworldencyclopedia.org/entry/Image:Commonbuckeye.JPG

http://www.newworldencyclopedia.org/entry/Image:Anemone_monterey_madrabbit.jpg

http://static.newworldencyclopedia.org/6/62/SeaUrchin.jpg

Classification of Animals

There are more than 1.5 million identified species

Classifying animals helps biologists make sense of this diversity

Scientists often correlate strength of relationship between species with the number of characteristics that they share

Animals are classified according to similarities in:body structurebody developmentsimilarity in DNA sequence

35 Phyla: 1 for vertebrates, the rest for invertebrates


InvertebratesChapter 15

Section 1: Simple Invertebrates

Section 2: Mollusks and Annelid Worms

Section 3: Arthropods

Section 4: Echinoderms


End of Slide

Simple InvertebratesSection 1

Objectives

• Describe how sponges and cnidarians get food, move around, and reproduce.

• Explain what a larva is.

• Describe the two body plans of cnidarians.

•.


End of Slide


Video clip: sponges


End of Slide

http://www.youtube.com/watch?v=nsHnUJUgZSE



• How Do Sponges Eat? Adult sponges stay in one place. A sponge sweeps water into its body through special cells called COLLAR cells.

• Reproduction Sexual reproduction: Each sponge produces BOTH eggs AND sperm!.Asexual reproduction: parent breaks off a chunk of cells that becomes another sponge

• Body structure Sponges have no symmetry, no body organs, no body tissues. They are just a collection of cells that work together.

Sponges

End of Slide


Cnidarians

• Two Body Forms A cnidarian body can have one of two forms— the medusa or the polyp form.MEDUSA: bowl shaped, swimming formPOLYP: vase shaped, attached to a surface (non-swimming)

• Stinging Cells All cnidarians have tentacles covered with stinging cells. They are used for defense and to capture food.

• Eating Catch animal with stinging cells. Use tentacles to pull prey into mouth. Move prey into gut, where it is digested. Expel waste through mouth.


End of Slide


Cnidarians

• Movement Cnidarians have “nerve nets” that signal their cells to move (beating jellyfish, somersaulting hydra)

•


End of Slide

http://www.youtube.com/watch?v=S926pTCYgHU

http://www.youtube.com/watch?v=12OmszObAkM


Cnidarians


End of Slide


Budding (Asexual Reproduction)


End of Slide

http://www.youtube.com/watch?v=a5oHMjGqjyo


Worms

• have long, narrow bodies, and no legs

• 3 kinds: flatworms, round worms, segmented worms

•Phyla: Platyhelminthes, Nematoda, Annelida

•What kind of symmetry?

•They have tissues, organs, and organ systems


End of Slide


Worms

• Nervous system: simple brain and sense organs

•Reproduction:

•some do asexual reproduction

•Most species can reproduce sexually•Male and female individuals•Hermaphrodites


End of Slide


Flatworms• Planarians Planarians are free-living. They live in freshwater lakes and streams. Most planarians are predators and scavengers. They insert a “feeding tube” into their prey. They have eyespots.

• Flukes Flukes are parasites. A parasite is an organism that invades and feeds on the body of a host. Most flukes live and reproduce inside the bodies of other animals.

• Tapeworms Tapeworms are parasites. They often have more than one host in their lifetime.

•All flatworms have ONE body opening! Mouth = anusCopyright © by Holt, Rinehart and Winston. All rights reserved.


Roundworms

•Roundworms have bodies that are long, slim, and round, like spaghetti.

•They have a digestive system that is a tube, open at both ends. (mouth is NOT the anus)


End of Slide

Mollusks and Annelid WormsSection 2

Annelid Worms (Segmented worms)

• Earthworms Earthworms are the most common annelid worms. Each earthworm has 100 to 175 segments.•Other segmented worms: leeches, sea-floor worms

•Have a one-way digestive system with mouth and anus

•Well-developed organ system

• Closed circulatory system: blood is held in blood vessels, can be pumped around the body


End of Slide


Mollusks

• Body structure: Soft, unsegmented body. Sometimes has a shell.

• Mantle: Thin tissue that covers internal organs

• Foot: Muscular organ

• Symmetry: Bilateral

•Digestive system: Two openings (mouth AND anus)


End of Slide


Mollusks

• Circulatory system: OPEN! (not like earthworms) Blood sloshes around the body cavity

• Gills: Allow oxygen from the water to enter the body

• 3 major groups of mollusks: gastropods, bivalves, cephalopods


Gastropods

The gastropods are the largest group of mollusks

Have ONE external shell OR NO shell at all

Examples: Snails, slugs


Ocean gastropods: video


Bivalves

Have two shells held together by hinges and strong muscles

Examples: clams, oysters, scallops, mussels

Giant clam: video


Cephalopods

• Ocean Dwelling

• Foot is adapted to form tentacles around mouth

• Carnivorous

•Examples: Octopuses, cuttlefish, nautiluses, squids

•Camouflage defense: video


End of Slide

Arthropods

Characteristics of Arthropods


• Segmented and Specialized: Like annelid worms, arthropods are segmented.

• Jointed Limbs called APPENDAGES: Legs or other body parts that bend at the joints.

• An External Skeleton: The hard, external structure that covers the outside of the body is an exoskeleton.

• Major Groups: Crustaceans, arachnids, centipedes and millipedes, insects

End of Slide

Arthropods

Kinds of Arthropods


•Other details:

•bilateral symmetry

•Open circulatory system

•Digestive system with TWO openings

•Sexual reproduction

End of Slide

Arthropods

Exoskeleton


• Waxy: protects the animal, prevents evaporation

• Molting: Process of shedding exoskeleton

End of Slide

Arthropods

Crustaceans


• 2 or 3 body sections

•5 or more pairs of legs

• 2 pairs of antennae

•Have gills

•Metamorphosis: change from larva form to adult form

End of Slide

Arthropods

Arachnids


• 2 body sections•1: head + midsection•2: abdomen (reproductive organs, some digestive organs)

•4 or more pairs of legs

• no antennae

End of Slide

Arthropods

Centipedes, millipedes


• 2 body sections

•Numerous pairs of legs

• Centipedes: one pair of legs per segment

•Millipedes: two pairs of legs per segment

•Video clip

End of Slide

Arthropods

Insects


• 3 body sections•1: Head•2: Thorax – legs and wings attach to this section• 3: Abdomen – contains internal organs

•6 legs

• Insects go through complete metamorphosis OR gradual metamorphosis

End of Slide

Arthropods

Complete Metamorphosis


• Egg Larva Pupa (enclosed in case) Adult

•Example: Butterflies

End of Slide

Gradual Metamorphosis• Egg Nymph (looks like a miniature adult) Adult

•Example: Grasshoppers and cockroaches

Stages of Complete Metamorphosis


Stages of Incomplete Metamorphosis


EchinodermsSection 4

Bellringer

Echinoderms include marine animals such as sea stars, sea urchins, and sea cucumbers. All these organisms are slow moving animals that live on the ocean floor. How do you think they protect themselves from predators?

Write your response in your science journal.



Objectives


• Describe the endoskeleton, nervous system, and water vascular system of echinoderms.

• Explain how an echinoderm’s body symmetry changes with age.

• Describe five classes of echinoderms.

End of Slide


Spiny Skinned


• Endoskeleton The name echinoderm means “ spiny skinned.” An echinoderm’s internal skeleton is called an endoskeleton.

Bilateral and Radial?

• Adults vs.. Larvae Adult echinoderms have radial symmetry. But they develop from larvae that have bilateral symmetry.

End of Slide


The Nervous System


• Endoskeleton All echinoderms have a simple nervous system similar to that of a jellyfish. Around the mouth is a circle of nerve fibers called the nerve ring.

Water Vascular System

• Fluid-Filled Canals The water vascular system is a system of canals filled with fluid. A water vascular system is illustrated on the next slide.

End of Slide

A Water Vascular SystemSection 4



Kinds of Echinoderms


• Brittle Stars and Basket Stars Brittle stars and basket stars look like sea stars. But these echinoderms have long, slim arms and are often smaller than sea stars.

• Sea Urchins and Sand Dollars Sea urchins and sand dollars are round. Their endoskeletons form a solid, shell-like structure.

End of Slide


Kinds of Echinoderms continued


• Sea Lilies and Feather Stars Sea lilies and feather stars have 5 to 200 feathery arms.

• Sea Cucumbers Like sea urchins and sand dollars, sea cucumbers have no arms. A sea cucumber has a soft, leathery body.

End of Slide

InvertebratesChapter 15

Concept Map


Use the following terms to complete the concept map on the next slide: cnidarians, symmetry, invertebrates, mollusks, annelid worms, snails, bilateral, sponges, coral, asymmetry.

Concept MapChapter 15


chapter 11: invertebrates copyright © by holt, rinehart and winston. all rights reserved

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