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Section 6.3: Kingdom Animalia pg. 182-197
Part 1: Invertebrates
Animal Kingdom
• Includes the very small to the very large organisms on Earth. • Animals: – are multicellular eukaryotes – are heterotrophic – reproduce sexually
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Animal Characteristics
These are used to classify animals into different phyla: 1. The number of Germ Layers – “germ” = cells in early stages – Most have 3 layers: ectoderm (outer), endoderm (inner) & mesoderm (middle)
2. Digestive Tract – Most animals use extracellular digestion – Incomplete digestive tract : only one opening (food & wastes use the same opening) – Complete digestive tract : separate openings for food & wastes.
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3. Body Symmetry – Asymmetrical Body : irregular shape (i.e. sponges, who are the simplest animals) – Symmetrical Body : most animals are balanced in their shape
Symmetry
There are 2 types of symmetry 1. Radial (Fig. 6.17a, pg. 185) 2. Bilateral (Fig. 6.17b, pg. 185)
4. Development of a Coelom – Coelom = a fluid-filled body cavity – The presence of a coelom allows for the development of more complex organ systems. – Animals with a coelom = coelomates – Animals without a coelom = acoelomates
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5. Reproduction – All animals reproduce sexually – Some also reproduce asexually – Some are hermaphrodites = have both male & female reproductive organs
Invertebrates (95% of Animal Kingdom)
• Examples include: (see Table 6.2, pages 183-184) – sponges – sea anemones – jellyfish – coral – planarians – tapeworms – leech – slug – clam – octopus – starfish – sand dollars, etc.
Invertebrate Characteristics
• Lack of internal structures • Reproduction includes sexual & asexual • Some are coelomate (i.e. earthworm) & some are acoelomate (i.e. flatworm)
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Invertebrate Characteristics
• Can have asymmetrical (i.e. sponges), radial (i.e. jellyfish) or bilateral body forms (i.e. earthworm).
There are over 30 phyla of invertebrates, but we will look at the major eight.
8 Phyla of Invertebrates
1. Porifera 2. Cnidaria 3. Platyhelminthes 4. Nematoda 5. Annelida 6. Mollusca 7. Echinodermata 8. Arthropoda
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Phylum Porifera
• Means “pore-bearing” • Example: Sponges
Phylum Cnidaria
• Means “thistle” • Examples: Jellyfish, corals, sea anemones, hydras
Phylum Platyhelminthes
• Means “flat, wide worms” • Examples: Tapeworms, flukes, planarians
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Phylum Nematoda
• Means “thread-like” • Examples: Pinworms, hookworms
Phylum Annelida
• Means “ring” • Examples: Earthworms, leeches, tubeworms
Phylum Mollusca
• Means “soft-bodied” • Examples: clams, oysters, squids, octopi, snails, slugs, scallops
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Phylum Echinodermata
• Means “spiny-skinned” • Examples: starfish, sea cucumbers, sand dollars, sea urchins
Phylum Arthropoda
• The MOST successful phylum!! • Over 1 million species have been identified. • Very diverse – some live at the bottom of the ocean, and some float in the air.
Examples of Arthropods
• Include: – Insects – Spiders – Shrimp – Barnacles – Lobster – Scorpions
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Arthropods…
• have jointed appendages • have bilateral symmetry • have a coelom • have a “tube within a tube” digestive system • reproduce sexually
Why are Arthropods So Successful? • Exoskeleton: – a rigid, jointed external skeleton – is waterproof and protects against water loss – they must shed their exoskeleton in order to grow.
Other Reasons Why They Are Successful… • The nature of their body segments & attached appendages. • Their well-developed nervous system. • Their structures & functions related to feeding themselves.
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Insects
• The most successful species on Earth. • But Why??? 1. They have many adaptations for feeding. 2. Most are small in size, allowing them to hide. 3. They move quickly and many have wings.
Insect Mimicry
• Some insects have an adaptation called mimicry. • Mimicry: the ability to look like something else.
Two Short Videos
• Insect Mimicry
• Phylum Arthropoda “How Stuff Works”
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Section 6.3: Part 1 Review Activities
• Do the “Survey of Invertebrates” handout. • Go to lab to do the Investigation 6C on pages 188-189.
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