Introduction to Invertebrates

5th Grade

Invertebrates

• Animals without backbones

• can have bilateral symmetry, radial symmetry and no symmetry

• Are part of the Animal Kingdom like vertebrates

What percent of all animals are invertebrates?

• 97% of all animals are invertebrates

Introduction to Sponges

Did you Know? Sponges are so different from most animals that you know that people used to think that they were plants.

How are sponges like plants? How are they like animals?

• Like plants, they stay in one place.

• Like animals, they take food into their bodies instead of making it themselves

• Like animals, they need oxygen to breathe.

Where do sponges live?

• 1) mostly in the ocean (99%)

• 2) rivers

• 3) lakes

• Attach themselves permanently to a solid location under water and do not move around

How many?

• Over 5,000 species of sponges!

Belongs to the phylum “porifera”

• Porifera = “having pores”

Body Structure: What type of animal symmetry do sponges have?

• Usually NO body symmetry

• They NEVER have tissues or organs

• A sponge looks like something like a hollow bag with a large opening at one end and many tiny pores covering its surface

Sponges

• Have no brain or central nervous system • How big are they? • Size: range in height from 1-200 cm and width

of 1-150 cm.

Sponge Adaptations

• Most sponges have spikes ---Why?

• Spikes: – Support its soft body – Keep the sponge upright in the water (since it has

no spine to do this) – Are a defense mechanism against predators

Sponge Body Structure

• Pores –small holes all over the sponge’s body that are used to allow water in

• Collar Cells –have whip-like structures that beat back and forth, helping water move through the sponge and trapping food

• Jelly-like Cells surrounding spikes –digest and distribute food, remove wastes, and form sperm or egg cells

Body Structure

• Collar Cell:

• Pores:

Osculum: an opening in the top of the sponge that allows wastes to exit

Take the Sponge Body Structure Tour!

• http://www.phschool.com/atschool/phsciexp/active_art/structure_of_a_sponge/index.html

Obtaining Food

• Sponges usually eat tiny single-celled organisms (usually microscopic life forms), as well as organic particles

Sponge Reproduction

• Reproduce both asexually and sexually

• Asexual reproduction is called “budding” – In budding, small sponges from the sides of an

adult sponge• Sexual reproduction – Reproduce sexually, but do NOT have separate

sexes (males and females) because sponges have both sperm and egg cells

Sponge Reproduction Cycle

All about Sponges! http://www.youtube.com/watch?v=RmPTM965-

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