Chapter 32 Flashcards
Animal bodies are held together by structural proteins such as _______
collagen
________ tissue and ________ tissue are unique, defining characteristics of animals
Nervous; muscle
Tissues
groups of similar cells that act as a functional unit
T/F: The diploid stage usually dominates the life cycle in animals
True
Cleavage
rapid cell division that occurs in the zygote after a sperm fertilizes an egg
blastula
a multicellular, hollow body created by cleavage
the blastula undergoes __________, forming a ______ with different layers of embryonic tissues
gastrulation; gastrula
Larva
a sexually immature organism in the early stages of a life cycle; morphologically distinct from the adult
metamorphosis
the change that a larva undergoes to become a juvenile
Juvenile
resembles an adult but is not yet sexually mature
Most animals, and only animals, have ________
Hox genes
Cadherins
a class of type-1 transmembrane proteins; they play important roles in cell adhesion
Ediacaran Biota
early members of the animal fossil record which dates back to about 560 million years ago
The Cambrian explosion
the event that marks the earliest fossil appearance of many major groups of living animals
The Cambrian Explosion occurred _____ to ___________ years ago
535; 525 million
Bilaterians
Most of the fossils from the Cambrian explosion
Bilaterians have the traits:
- Bilaterally symmetric form
- Complete digestive tract
- One-way digestive system
Coral reefs emerged during the ________ Era and became important marine ecological niches
Mesozoic
mammals first emerged in the __________
Mesozoic Era
the Mesozoic Era occurred _______________ years ago
251-65.5 Million
the Cenozoic Era occurred __________ years ago
65.5 Million
the Cenozoic Era followed the ____________ of both terrestrial and marine animals
mass extinctions
body plan
a set of morphological and developmental traits by which zoologists sometimes categorize animals by
Some animals have __________, with no…
radial symmetry; front and back, or left and right
Bilateral symmetry
Two-sided symmetry
Bilaterally symmetrical animals have…
a dorsal side, a ventral side, an anterior, and a posterior
Dorsal
A top side
Ventral
A bottom side
Anterior
A front end
Posterior
A back end
Ectoderm
the germ layer covering the embryo’s surface
Endoderm
the innermost germ layer that lines the developing digestive tube, called the archenteron
Diploblastic
animals that have ectoderm and endoderm
Triploblastic
animals that also have an intervening mesoderm layer between the ectoderm and endoderm
Most triploblastic animals possess a __________
body cavity
Coelom
a true body cavity and is derived from the mesoderm
Coelomates
animals that possess a true coelom
Psuedocoelom
a body cavity that only has mesoderm on one side of the cavity
pseudocoelomates
Triploblastic animals that possess a pseudocoelom
acoelomates
Triploblastic animals that lack a body cavity
In protostome development, cleavage is _______ and __________
spiral; determinate
In deuterostome development, cleavage is _______ and __________
radial; indeterminate
blastopore
forms during gastrulation and connects the archenteron to the exterior of the gastrula
In protostome development, the blastopore becomes the _______
mouth
In deuterostome development, the blastopore becomes the _______
anus
