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