Download Chapter_29_Part_1_AP_Biology_modified

Overview: Welcome to Your Kingdom
• The animal kingdom extends far beyond humans
and other animals we may encounter
Video: Coral Reef
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Concept 32.1: Animal are multicellular, heterotrophic
eukaryotes with tissues that develop from embryonic layers
• There are exceptions to nearly every criterion for
distinguishing animals from other life forms
• Several characteristics, taken together, sufficiently
define the group
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Nutritional Mode
• Animals are heterotrophs that ingest their food
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Cell Structure and Specialization
• Animals are multicellular eukaryotes
• Their cells lack cell walls
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Their bodies are held together by structural
proteins such as collagen
• Nervous tissue and muscle tissue are unique to
animals
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Reproduction and Development
• Most animals reproduce sexually, with the diploid
stage usually dominating the life cycle
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• After a sperm fertilizes an egg, the zygote
undergoes cleavage, leading to formation of a
blastula
• The blastula undergoes gastrulation, forming
embryonic tissue layers and a gastrula
Video: Sea Urchin Embryonic Development
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-2_3
Blastocoel
Cleavage
Cleavage
Eight-cell stage
Zygote
Blastocoel
Endoderm
Ectoderm
Gastrula
Blastopore
Gastrulation
Blastula
Cross section
of blastula
• Many animals have at least one larval stage
• A larva is sexually immature and morphologically
distinct from the adult; it eventually undergoes
metamorphosis
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Concept 32.2: The history of animals may span
more than a billion years
• The animal kingdom includes not only great
diversity of living species but also the even greater
diversity of extinct ones
• The common ancestor of living animals may have
lived 1.2 billion–800 million years ago
• This ancestor may have resembled modern
choanoflagellates, protists that are the closest
living relatives of animals
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Concept 32.3: Animals can be characterized by
“body plans”
• Zoologists sometimes categorize animals
according to morphology and development
• A grade is a group of animal species with the
same level of organizational complexity
• A body plan is the set of traits defining a grade
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Symmetry
• Animals can be categorized according to the
symmetry of their bodies, or lack of it
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Some animals have radial symmetry, the form
found in a flower pot
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-7a
Radial symmetry
• The two-sided symmetry seen in a shovel is an
example of bilateral symmetry
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-7b
Bilateral symmetry
• Bilaterally symmetrical animals have:
–
A dorsal (top) side and a ventral (bottom) side
– A right and left side
– Anterior (head) and posterior (tail) ends
– Cephalization, the development of a head
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Tissues
• Animal body plans also vary according to the
organization of the animal’s tissues
• Tissues are collections of specialized cells
isolated from other tissues by membranous layers
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Animal embryos have concentric layers called
germ layers that form tissues and organs
• Ectoderm is the germ layer covering the embryo’s
surface
• Endoderm is the innermost germ layer
• Diploblastic animals have ectoderm and
endoderm
• Triploblastic animals also have an intervening
mesoderm layer
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Body Cavities
• In triploblastic animals, a body cavity may be
present or absent
• A true body cavity is called a coelom and is
derived from mesoderm
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-8a
Coelom
Body covering
(from ectoderm)
Digestive tract
(from endoderm)
Coelomate
Tissue layer
lining coelom
and suspending
internal organs
(from mesoderm)
• A pseudocoelom is a body cavity derived from the
blastocoel, rather than from mesoderm
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-8b
Body covering
(from ectoderm)
Pseudocoelom
Digestive tract
(from endoderm)
Pseudocoelomate
Muscle layer
(from
mesoderm)
• Acoelomates are organisms without body cavities
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-8c
Body covering
(from ectoderm)
Wall of digestive cavity
(from endoderm)
Acoelomate
Tissuefilled region
(from
mesoderm)
Protostome and Deuterostome Development
• Based on early development, many animals can
be categorized as having protostome or
deuterostome development
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Cleavage
• In protostome development, cleavage is spiral and
determinate
• In deuterostome development, cleavage is radial
and indeterminate
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-9a
Protostome development
(examples: molluscs,
annnelids, arthropods)
Eight-cell stage
Spiral and determinate
Deuterostome development
(examples: echinoderms,
chordates)
Eight-cell stage
Radial and indeterminate
Cleavage
Coelom Formation
• In protostome development, the splitting of solid
masses of mesoderm to form the coelomic cavity
is called schizocoelous development
• In deuterostome development, formation of the
body cavity is described as enterocoelous
development
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-9b
Protostome development
(examples: molluscs,
annnelids, arthropods)
Deuterostome development
(examples: echinoderms,
chordates)
Coelom formation
Coelom
Archenteron
Coelom
Mesoderm
Blastopore
Schizocoelous: solid
masses of mesoderm
split and form coelom
Blastopore
Mesoderm
Enterocoelous:
folds of archenteron
form coelom
Fate of the Blastopore
• In protostome development, the blastopore
becomes the mouth
• In deuterostome development, the blastopore
becomes the anus
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 32-9c
Protostome development
(examples: molluscs,
annnelids, arthropods)
Deuterostome development
(examples: echinoderms,
chordates)
Mouth
Anus
Digestive tube
Mouth
Mouth develops
from blastopore
Anus
Anus develops
from blastopore
Fate of the blastopore