Announcements This Saturday, May 3 is the last day to withdraw and still get a W on your transcript. Office hours this Thursday from 5-6 pm in B267. Bring your textbook and lecture notes to lab! 10 points extra credit available until 5/20 (day of final exam) for going to writing center or meeting with a counselor. Laney Idol, Jeopardy! and Potluck on 5/13

What is an animal? An animal is a eukaryotic, multicellular, heterotrophic organism lacking cell walls that feeds by eating other organisms.

Clicker Question What distinguishes animals from plants? A.Animals are eukaryotic, while plants are prokaryotic B.Plants can be either single-celled or multicellular, while animals are always multicellular C.Animals are heterotrophs while plants are autotrophs D.Animals have cell walls, while plants do not

Clicker Question What distinguishes animals from seaweeds? A.Seaweeds are single-celled while animals are multicellular B.Seaweeds are prokaryotic while animals are eukaryotic C.Seaweeds are absorptive heterotrophs, while animals are heterotrophs that eat other organisms D.Seaweeds make their own food, while animals must find their own food.

Clicker Question What distinguishes animals from fungi? A.Animals have no fun while fungi are always fun guys B.Fungi have cell walls while animals do not C.Animals are heterotrophs while fungi are not D.Fungi are eukaryotic while animals are prokaryotic

Phylum Tardigrada

The origin of animals Oldest fossils are million years old Common ancestor of all animals was likely a colonial protist Grandpa

The Cambrian Explosion mya

Animal Phylogeny

Sponges (9,000 species)

Cnidarians (10,000 species) The first appearance of body tissues among animals Includes corals, sea anemones, and jellyfish Cnidarians have radial symmetry and stinging tentacles, which capture prey. Incomplete digestive tract, or gut (mouth is the same as the anus

Two Body Types

Coral Reefs

Color from symbiosis between coral and zooxanthellae

Clicker Question True/False: Zooxanthellae belong to which group of organisms? A.Archaea B.Protists C.Fungi D.Plants E.Bacteria

Thought Question How might global warming impact coral reefs? Hints: Photosynthesis: 6CO2 + 6 H2O >> 6O2 + Glucose Too much oxygen is bad for corals

Coral Bleaching

Molluscs (93,000 species) Includes snails, slugs, octopuses, squid, oysters and clams Most live in the ocean and have shells Development of a body cavity with a coelom, and a complete digestive tract (the mouth is a separate opening from the anus). Basic body plan has three parts: a foot, a visceral mass, and a mantle.

Mollusc body plan

Garden Snail Mouth

Three groups of molluscs Gastropods

Three groups of molluscs Bivalves (two shells hinged together), including mussels, clams, scallops, oyster

Three groups of molluscs Cephalopods (octopuses, squid)

Flatworms (20,000 species) Ribbonlike worms that lack a true body cavity and have incomplete digestive tract (mouth is same as anus) They range from 1 mm-20 m (65 feet) in length Many are parasitic and cause human diseases They live in marine, freshwater, and damp terrestrial habitats

Tapeworm (gross, I know)

Annelids (16,000 species) Worms with segmented bodies that live in marine, freshwater, and soil habitats They have a complete digestive tract and a body cavity with a coelom There are 3 main groups: earthworms, polychaetes, and leeches

Earthworms

Giant Earthworm

Polychaetes

Leeches

Osedax, a type of polychaete bone worm (an annelid) that lives on the sunken bones of whale carcasses.

Discussion Questions 1.How are these bone worms sexually dimorphic? Where did we see the term sexual dimorphism before? 2.How is the feeding strategy of bone worms different from most annelids? What phylum is it most similar to?

Roundworms/Nematodes (25,000 species) Live in soil, freshwater, and as parasites in the tissue of plants and animals Extremely abundant—90,000 nematodes were found in a single rotting apple.

Roundworm Diversity Parasitic roundworms cause trichonosis

Arthropods (over 1 million species) Diverse AND abundant (150 million arthropod specimens for every human on Earth) They have an exoskeleton, jointed appendages, and specialized body segments Four main groups: arachnids, crustaceans, millipedes/centipedes, and insects

Arachnids Includes spiders, ticks, scorpions, and mites. Arachnids have 8 legs.

Crustaceans

Millipedes/Centipedes

Insects The most diverse group of organisms on Earth Body has 3 segments: head, thorax, and abdomen Insects have 6 legs in 3 pairs Several recently evolved insect groups go through metamorphosis

Insect Body Plan

Metamorphosis

Thought Question Why are insects so diverse? Hint: What do you need to get new species to form?

Thought Question Why are insects so diverse? -They have short generation times -They co-evolved with angiosperms -Flight was a key innovation that allowed them to explore more niches -They are generally small

Clicker Question Which of these insects do you like best? A.Beetles B.Butterflies/Moths C.Flies D.True Bugs E.Bees/wasps

Echinoderms (7,000 species) Marine invertebrates with spiny surfaces and an endoskeleton They have a water vascular system, kind of like a plant, that circulates water for gas exchange and waste removal. Tube feet allow for movement and feeding Includes starfish, sea urchins, sand dollars, and sea cucumbers

Echinoderm Diversity

Sea Cucumbers