Ch 21: Animals (Exam 2) Flashcards
Invertebrate
animals without backbones (insects, crustaceans, spiders)
Defining characteristics of animals
-multicellular organisms
-eukaryotic cells
-lack cell walls
-heterotrophs
-the diploid zygote divides rapidly
-animal cells secrete and bind to a nonliving substance called the extracellular matrix
Radial Symmetry vs Bilateral Symmetry
Radial Symmetry-a body form in which multiple similar parts are arranged around a central axis (hydras, sponges, jellyfish, sea stars)
Bilateral Symmetry-in which only one plane can divide the animal into mirror images (crayfish, head is anterior, and tail is posterior)
Complete digestive tract vs Incomplete digestive tract
Complete digestive tract-food passes in one direction from mouth to anus
Incomplete digestive tract-in which the mouth both takes in food and ejects wastes
Gastrovascular Cavity-secretes digestive enzymes and distributes nutrients to all parts of the animals body-this is how digestion occurs in species with an incomplete digestive tract!
Distinguishing characteristics of sponges
-unlike other animals, sponge cells do not interact to form tissue
-pore-barrier bodies, hollow bodies
-either symmetrical or asymmetrical
-no digestive tract
Cnidarians
they are AQUATIC!
include jellyfish, hydras, corals, and sea enmity
-most are marine, although some live in fresh water
-they have radial symmetry, incomplete digestive tracts, they are named for their stinging cells
What are the major groups of Mollusks?
Mollusks-form the second largest phylum, and they include many familiar animals in land, fresh water, and the ocean
3 groups;
BIVALVES-(have two part hinged shells) oysters, clams, scallops, muscles
GASTROPODS-(broad flat foot in which they crawl) snails, slugs, limpets
CEPHALOPODS-(tentacles connect to head of animal) octopus, squid
What is the animal phylum with the largest number of species?
(Arthropoda) is the largest phylum in the animal kingdom
-includes insects, lobsters, mites, crabs, mosquitos, tics, flees
-thrive on land, air, and oceans
-more then 1 million species
Major groups of Arthropods
5 groups:
TRILOBITES-extinct
CHELICERATES-spiders, scorpions
MYRIAPODS-millipede, centipede
CRUSTACEANS-crab, lobster
INSECTS-beetle, dragonfly, moth
What is the function of vertebrae in the skeleton?
protects and supports the spinal chord
What vertebrae groups have an Amnion around the embryo?
Amnion-a sac enclosing the developing embryo of a reptile or mammal (reptiles, birds, mammals)
Endotherms vs Ectotherms
Endo-maintain their body temp mostly by using heat generated from their own metabolism (birds, mammals, some fish)
Ecto-body temp fluctuates with their environment, these animals lack internal mechanisms that keep their temp within a narrow range (fish, invertebrates, amphibians, and most reptiles)
Examples of jawless fish
Hagfish-cartilage makes up the cranium and supports the tail (not vertebrae’s)
Lamprays-the simplest organisms to have cartilage around the nerve chord so they are (vertebrae’s)
How are sharks structurally different from all other fish?
sharks have skeletons entirely made up of cartilage
Examples of Amphibians
Amphibians-“double life” can live in freash water and on land
-frogs, caecillion, salamanders
