Ch. 9 Flashcards
bilateral symmetry
a body plan in which an organism can be divided into two parts that are nearly mirror images of each other.
radial symmetry
asymmetry
a body plan in which an organism cannot be divided into any two parts that are nearly mirror images.
adaptation
an inherited trait that increases an organism’s chance of surviving.
hydrostatic skeleton
a fluid-filled internal cavity surrounded by muscle tissue.
exoskeleton
a thick, hard outer covering; protects and supports an animal’s body.
endoskeleton
the internal rigid framework that supports humans and other animals.
parasite
an animal that survives by living inside or on another organism, gets food from the organism, and does not help in the organism’s survival.
mantle
a thin layer of tissue that covers a mollusk’s internal organs.
molting
a process in which an outer covering, such as an exoskeleton, is shed and replaced.
metamorphosis
a developmental process in which the body form of an animal changes as it grows from an egg to an adult.
notochord
a flexible, rod-shaped structure that supports the body of a developing chordate.
pharyngeal pouch
grooves along the side of a developing chordate.
gill
an organ that exchanges carbon dioxide for oxygen in the water.
amnion
a protective membrane that surrounds an embryo.
ectotherm
an animal that heats its body from heat in its environment.
endotherm
an animal that generates its body heat from the inside.
mammary gland
special tissue that produces milk for young mammals.
