Download PASS Review—Animals Name: The animal kingdom is divided into

PASS Review—Animals
Name:
The animal kingdom is divided into 35 different phyla; classified into two groups (invertebrates and
vertebrates) based on internal and external features. All animals are multicellular heterotrophs.
Vertebrates (fish, amphibians, reptiles, birds, and mammals) all have backbones; an endoskeleton
(internal); muscles; blood in vessels; lungs or gills for breathing; skin, legs, wings, or fins for
movement; nervous system with brain; fish, amphibians, and reptiles are cold-blooded, or
ectothermic; birds and mammals are warm-blooded, or endothermic. Ectotherms gain heat from
the environment; they bask to get warm; they eat less; Endotherms maintain a constant body
temperature; they need to eat more often; can live in more environments.
Vertebrates: Fish: ectotherms; gills; scales; Amphibians: ectotherms; gills when young; lungs when
adult; metamorphosis; jelly-like eggs; can breathe through skin; frogs, toads, salamanders;
Reptiles: ectothermic; lungs; lay eggs; scales; Birds: endothermic; lungs; lay eggs; feathers; beak,
two wings, two feet; Mammals: endothermic; lungs; hair or fur; live babies; produce milk;
Invertebrates: Sponges: pores that filter food and oxygen from water; segmented worms: true
nervous system, blood in vessels, and digestive system—take in oxygen through its skin; examples
are earthworm and leech; mollusks: soft bodies with muscular foot; snails, slugs, clams, octopus;
arthropods: jointed legs, segmented bodies, exoskeletons, some have wings; insects; arachnids,
crustaceans; echinoderms: tube feet; sea starts, sea urchins, sand dollars
Animals have special structures that enable them to survive in their environment. Structures for
defense, structures for movement, structures to obtain resources: claws, teeth, strong legs,
camouflage, mimicry, etc.
Animals respond to internal and external stimuli with physical and behavioral responses. Examples of
physical responses: shedding, sweating, panting, shivering, blinking, food gathering, storing food,
and storing nutrition in the form of fat. Examples of behavioral responses: hibernation, migration,
defense (camouflage, smells, stingers, ejection, mimicry, grouping), courtship (adults attract a mate).
Examples of internal stimuli: hunger, thirst, sleep, pain.
Behavior is an activity or action, in response to changes in the environment, which helps an organism
survive. Learned behaviors: imprinting—newborn animals recognize and follow the first moving
object they see. Can’t be reversed. Ex: baby ducks following their mother. Conditioning—an animal
learns that a particular stimulus and its response will lead to a good or bad result. Ex: child learns
touching hot objects causes pain. Inherited behaviors (instincts)—passed from parent to offspring.
Ex: fish swimming, babies crying, birds building a nest.