Symmetry A Visual Presentation Bilateral Symmetry n Bilateral

Symmetry: A Visual Presentation

Bilateral Symmetry n Bilateral symmetry occurs when one half of an object is the mirror image of the other half. n Symmetry exists all around us and many people see it as being a thing of beauty.

Is a butterfly symmetrical?

At the beach there a variety of shells with symmetry.

Under the sea there also many symmetrical objects such as these crabs and this starfish.

Animals that have bilateral symmetry

THESE MASKS HAVE bilateral SYMMETRY These masks have a line of symmetry from the forehead to the chin. The human face also has a line of symmetry in the same place.

Human Bilateral Symmetry The 'Proportions of Man' is a famous work of art by Leonardo da Vinci that shows the symmetry of the human form.

Classification 4. 1: Classify animals according to type of skeletal structure, method of fertilization & reproduction, body symmetry, body coverings, & locomotion.

Phylum Porifera: asymmetrical Invertebrate, no body tissues or organs n Filter feeders n Reproduce sexually w/fertilization & asexually by budding n Do not move as adults—only when budding n

Phylum Porifera: the sponges n This is what a sponge looks like; notice the range of colors.

Phylum Porifera n A sponge reproducing asexually through budding. n A sponge doesn’t look this.

Phylum Cnidaria: corals & anemones n n n n Invertebrates Have stinging cells (pneumatocysts) for hunting & protection Ingest food into a central body cavity Radial symmetry Many adults can move to escape danger or get food External sexual reproduction Asexual reproduction through budding

Phylum Cnidaria: corals and anemones n Notice the crab inside Clownfish here

Phylum Cnidaria: corals and anemones n Brain coral Notice the radial symmetry n

Worms are in 3 different phyla n 1. Flatworms = Phylum Platyhelminthes n 2. Roundworms = Phylum Nematoda n 3. Segemented worms = Phylum Annelida

Worms n Invertebrates n Long bodies with no legs n Bilateral symmetry n Possess tissues, organs, and organ systems n Reproduce sexually and asexually

Flatworms: Phylum Platyhelminthes

Roundworms: Phylum Nematoda

Segmented Worms: Phylum Annelida

Phylum Mollusca: the mollusks n Invertebrates n Soft, unsegmented bodies often covered by a shell n Bilateral symmetry n 3 major groups: gastropods, bivalves, cephalopods

Phylum Mollusca: the mollusks, gastropods n Example: snails n Have single external shell or no shell at all n Move by use of a muscular foot

Phylum Mollusca: the mollusks, gastropods

Phylum Mollusca: the mollusks, bivalves n 2 -shelled mollusks that filter feed n Examples: oysters, clams, scallops n Adult bivalves stay in one place or move slowly through the water

Phylum Mollusca: the mollusks, bivalves n Scallop Oysters

Phylum Mollusca: the mollusks, cephalopods n Examples: octopus, squid, cuttlefish, nautilus n Ocean-dwelling w/a “foot” adapted to form tentacles around its mouth n Not all have shells n Capture prey by using tentacles n Swim with jet propulsion

Phylum Mollusca: the mollusks, cephalopods n Squid, nautilus, cuttlefish, and octopus

Birds are in the Phylum Chordata n n Endothermic (produce & maintain body heat) Vertebrate w/4 chamber hear Bodies covered w/feathers MOST can fly using their wings – Puffins, penguins, kiwi, rheas, emus, & ostriches don’t n n n Internal, sexual reproduction & lay eggs Bilateral symmetry Parents care for babies until they can fly

Bird examples n Kiwi Emu Puffin (can fly but doesn’t usually)

Mammals are in the Phylum Chordata Endothermic n Vertebrate w/4 chamber heart n Skin covered w/fur or hair n Most born live & nursed with mother’s milk n Most walk or run on 4 limbs n Bilateral symmetry n Reproduce with internal, sexual reproduction n

Mammals are in the Phylum Chordata n Classified into 3 groups based on how their young develop 1. 2. 3. – Monotremes Marsupials Placentals Mammals care for young for an extended time.

Mammals: monotremes n most primitive mammals n There are three species of monotremes, the duck-billed platypus (Ornithorhynchus) and two spiny anteaters, or echidnas (Tachyglossus and Zaglossus). These mammals lay eggs; after the babies hatch, the mothers nourish their young with milk. Today, monotremes live only in Australia and New Guinea. The name monotreme means "one-holed, " referring to the cloaca, a single hole that serves the urinary tract, anus, and reproductive tract in monotremes. n n n

Monotremes n Duck-billed platypus Echidna

Marsupial Mammals n Marsupials (Megatheria) are pouched mammals whose babies are born in a very undeveloped state; the young then attach themselves to their mother's nipple. – Many marsupials have a pouch that encloses the young. n The biggest marsupial is the human-sized red kangaroo (Macropus rufus); the smallest marsupial, the pilbara (Ningaui timealeyi), would fit in a person's hand. n Some commonly-known marsupials include the kangaroo, opossum, Tasmanian devil, and koala. The only marsupial in North America is the Virginia opossum. n Marsupials evolved during the late Cretaceous period, about 100 to 75 million years ago, during the time of the dinosaurs.

Marsupial Mammals n Virginia opossum Koala

Marsupial Mammals n 3 -week old red kangaroo

Marsupial Mammals n The pilbara mouse, world’s smallest marsupial n Tasmanian devil

Phylum Arthropoda: the arthropods Exoskeleton n Segemented body n Jointed appendages n Bilateral symmetry n Most reproduce sexually n Specialized mouth parts for chewing food n Move through use of legs n

Phylum Arthropoda n Includes crustaceans, arachnids, centipedes, millipedes, and insects n Insects have wings for flying n Crustaceans include crabs and shrimp n Arachnids = spiders & ticks n Insects = mosquitoes, bees, grasshoppers, crickets

Phylum Arthropoda: Crustaceans n Woodlouse n Shrimp Crab

Phylum Arthropoda: Arachnids

Phylum Arthropoda: Centipedes and Millipedes n Centipedes with distinct poison fangs Millipedes

Phylum Arthropoda: insects

Objective 6. 1: Describe protective adaptations of organisms, including mimicry, camoflage, and chemical defense.

Terms defined n Mimicry: defense strategy; an adaptation of an organism that allows it to look like a more dangerous one—see p. 727 in text n Camouflage: defense strategy/protection; an adaptation that provides organisms with the ability to blend in with their environments n Chemical defense: defense strategy/protection that allows organisms to poison predators if eaten or threatened; often are bright colored warning predators of poisnous nature

How many butterflies do you see?