Presentation on theme: "Apply Concepts Design a “new” invertebrate"— Presentation transcript:
1Apply Concepts Design a “new” invertebrate Apply Concepts Design a “new” invertebrate. Create and illustration on which you point out its body plan features. Then show its place on the cladogram of invertebrates and write a caption explaining how its features helped you decide where it belongs.
2Ch 26 Animal Evolution and Diversity 26.1 Invertebrate Evolution and Diversity
3Fossil evidence indicates that the first animals began evolving long before the Cambrian Explosion.
4Origins of the Invertebrates Roughly 3 billion years after the first prokaryotic cells evolved, all prokaryotes and eukaryotes were single-celledAnimals evolved from ancestors they shared with organisms called choanoflagellatesSingle-celled eukaryotes that sometimes grow in coloniesSimilar to sponges.
5Traces of Early Animals Oldest evidence of multicellular life comes from microscopic fossils that are roughly 600 million years oldFirst animals were tiny and soft-bodied, so few fossilized bodies exist.
6Ediacaran Fauna Before the Cambrian Period From the Ediacara Hills of AustraliaFossils 565 to about 544 million years oldFlat and lived on the bottom of shallow seasLittle evidence of cell, tissue, or organ specialization, and no organization into a front and back end.
7Cambrian Explosion Cambrian Period began about 542 million years ago Burgess Shale of CanadaFossils show that over a period of 10–15 million years, animals evolved complex body plans, including specialized cells, tissues, and organs.
8By the end of the Cambrian Period, all the basic body plans of modern phyla had been established Later evolutionary changes, which produced the more familiar body structures of modern animals, involved variations on these basic body plans.
9Invertebrates are the most abundant animals on Earth.
10Sponges Phylum: Porifera Most ancient members of the kingdom Animalia Multicellular, heterotrophic, lack cell walls, and contain a few specialized cells.
11Cnidarians Phylum: Cnidaria Includes jellyfishes, sea fans, sea anemones, hydras, and coralsAquatic, soft-bodied, carnivorous, radially symmetrical animals with stinging tentacles arranged in circles around their mouths.
12Arthropods Phylum: Arthropoda Includes spiders, centipedes, insects, and crustaceansBodies divided into segments, a tough external skeleton called an exoskeleton, cephalization, and jointed appendages (legs and antennae)Appeared in the sea about 600 million years ago.
13Nematodes (Roundworms) Phylum: NematodaUnsegmented worm with pseudocoeloms, specialized tissues and organ systems, and digestive tracts with two openingsMore closely related to the arthropods than flatworms.
14Flatworms Phylum: Platyhelminthes Soft, unsegmented, flattened worms that have tissues and internal organ systemsSimplest animals to have three embryonic germ layers, bilateral symmetry, and cephalizationNo coelms.
15Annelids Phylum: Annelida Includes earthworms, some marine worms, and leechesWorms with segmented bodies and a true coelom.
16Mollusks Phylum: Mollusca Includes snails, slugs, clams, squids, and octopiSoft-bodied animals that have an internal or external shellHave true coeloms and complex organ systemsMay have a trochophoreImmature free-swimming larva stage.
17Echinoderms Phylum: Echinodermata Includes sea stars, sea urchins, and sand dollarsHave spiny skin and an internal skeletonHave a water vascular system that include suction- cuplike tube feetDeuterostomes.