Download Document

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 550-575 million years old
Common ancestor of all animals was likely a colonial protist
Grandpa
The Cambrian Explosion
535-525 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
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