Download Bio II Chapter 32 - Marissa Junior/Senior High School

Bio II
Chapter 32
INTRODUCTION TO ANIMALS
Animals: multicellular, heterotrophic (eat for energy)
organisms that
lack a cell wall.
Vertebrate
 Animals that have a
backbone
invertebrate
 Animals that do not
have a backbone
 Account for more than
95% of all animal
species
Characteristics of animals
Multicellular
Organization
Heterotrophy
Sexual
Reproduction
and
Development
Movement
1. Multicellular Organization
•
all bodies are multicellular
•
Some have larger # than others, 50 – 100 trillion cells
•
Cells do not lead independent lives
•
Each cell depends upon the presence and functioning of other cells
•
Causes a “division of labor” among cells: each has a job
SPECIALIZATION: adaptation of a cell for a particular
function
Each cell has a
“job” to do,
from digesting
food, to
removing
waste, to
reproduction.
Cell: smallest
unit that can
perform life
processes
Specialization Heirarchy
cells
Tissue: group of
cells that perform a
particular function
Organ: group of tissues that
perform a particular function
System: group of organs that perform a
particular function
2. Heterotrophy
 Heterotrophy: to obtain complex organic molecules
from other sources
 Animals accomplish this through INGESTION
 INGESTION: take in organic material or food
3. Sexual Reproduction & Development
Asexual
Sexual
 SEXUAL REPRODUCTION:
 2 haploid gametes merge
zygote

Zygote: diploid cell that results from the fusion of the gametes

The zygote undergoes mitotic cell division (Development)

The big mass of cells undergoes DIFFERENTIATION: cells
become specialized and therefore differentiate from each
other.
4. Movement
Nervous
tissue
MOVEMENT
comes from
their
interrelationship
Muscle
tissue
ORIGIN & CLASSIFICATION
 Taxonomy: the science of describing, naming, and
classifying organisms
 Scientists use a “phylogenic diagram”
relate similar organisms
page 653 to
CLASSIFICATIONS
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Domain: Eukarya, Bacteria, Archaea
Kingdom Animalia, Plantae, Eubacteria,
Archaebacteria, Protista, & Fungi
Phylum
Class
Order
Family
Genus
Species
The 1st Animals
 Probably arose from the sea
 Evolved from protists
 First to be multicellular
 Had flagella
 See chart on page 653. This phylogenic diagram is a
HYPOTHESIS for the relationship in the animal
kingdom .
 Far right: Chordata
Chordates
 Chordate: animals with a notochord (a firm, flexible
rod of tissue located in the dorsal part of the body.
 At some stage of development, all chordates have:
 Notochord:
 Dorsal Nerve Cord: a hollow tube above the notochord
 Pharyngeal pouches: small “outpockets” of the anterior
digestive tract.
Body Structure of Invertebrates
Those that lack true
tissues and an
organized body
shape
Those that have very
organized tissues
and a consistent
body shape
4 elements of body structure
Patterns of
Symmetry
Germ
Layers
Body
Cavities
Body
Structure &
Relatedness
1. Patterns of Symmetry p655
 Symmetry: body arrangement in which parts that lie
on opposite sides of an axis are identical
Asymmetrical
Radial
Bilateral
Asymmetrical
 Asymmetry: do not display any symmetry
 Animals have the simplest body plan of all
 Example: sponges
Radial Symmetry
 Radial Symmetry: a body plan in which the parts are
organized in a circle around an axis
 Animals that have a top and bottom side
 They do not have a front, back, right or left end.
 Example: cnidarians (sea anemone) page 655
Bilateral Symmetry
 Bilateral Symmetry: having similar halves on either
side of a central plane
Dorsal
( back side)
Ventral
( abdomen side)
Anterior
(toward the head)
Posterior
(toward the tail)
 Cephalization: concentration of brain structures in
anterior of animal
Example: squirrel
2. Germ Layers
 Tissue layers in the embryos of all animals except
sponges. (Sponges have no true tissue.)
 Can be 2 or 3 layers, depending upon the organisms.
 Every organ and tissue arises from a germ layer.
3. Body Cavities
 Body-cavity: a fluid-filled space that forms between
the digestive tract and the outer wall of the body
during development
 Not all invertebrates have a body cavity
Aid in
movement
by
providing a
firm, fluid
structure
against
which
muscles can
contract
Allows for
movement
of the
external
body,
compared
to the
internal
body
Acts as a
reservoir
and
medium of
transport
for
nutrients
and wastes
4. Body Structure & Relatedness
Similarity in body plans allows
for
classification
Predicting
the past
relationships
Invertebrate
 7 main characteristics
Symmetry
Support of
the body
Segmentation
Digestive &
Excretory
systems
Respiratory &
Circulatory
systems
Nervous
system
Reproduction
&
Development
1. Invertebrate Symmetry
Radial Symmetry
Bilateral Symmetry
 Example: jellyfish
 Allows for
 Allows animal to
cephalization
 Most invertebrates
have this type of
symmetry
 Examples range from
slugs to squids
receive stimuli from all
directions
2. Invertebrate Segmentation
 Segmentation: body composed of a series of
repeating similar units
 Simplest form seen in earthworm
 More complex form seen in crayfish; fusion of
segments to create a head and chest region
3. Invertebrate Support of the Body
 Very diverse means of support
 “natural sponge” in stores: that is the dried skeleton
 Roundworms: pressure of fluid-filled body cavity
EXOSKELETON:
1. rigid outer covering that protects the soft tissues of many
animals
2. Limits the size of the animal
3. May impede the movement
4. Does not grow; must be shed as animal grows
Examples: crayfish
4. Invertebrate Respiratory & Circulatory
Systems
Respiratory
Circulatory
 Produce CO2: therefore
 2 types of circulatory
must have gas exchange
 Gas exchange: occurs best
in moist environment
 Some invertebrates: it
occurs across the body
covering. Others: have
GILLS: organs that consist
of blood vessels that
exchange gas in water
systems:
 OPEN: fluid pumped thru
vessels and into body cavity
and back to heart

Ex.: some mollusks &
arthrodpods
 CLOSED: Heart pumps
blood thru vessels and into a
simple loop back to the heart

Ex.: annelids
5. Invertebrate Digestive & Excretory Systems
Digestive
Excretory
 Simpler animals: occurs within
 Simpler animals: waste is
individual cells
 More complex animals: has a
digestive tract (gut) in which
nutrients are absorbed
excreted as NH3 (ammonia)
 More complex animals: NH3 is
filtered and converted to less
toxic substances; water is
reabsorbed by body
6. Invertebrate Nervous System
Sponges (simpler animals)
Mollusks (more complex)
 Have no neurons to
 Very diverse system
loosely connected
neurons
 Can contract body in
response to stimuli
 Very complex animals
can exhibit decisionmaking behavior (like
the octopus)
7. Invertebrate Reproduction & Development
Reproduction
Development
 Both sexual & asexual
 Indirect development: has an
 Some are
“hermaphrodites”:
both sexes
ex. Earthworm
Produces both male &
female gametes
intermediate stage called a larva
stage.
Larva: immature, free-living form
of adult
 Direct development: young animal
born with same appearance and
way of life it will have as an adult
No larva stage
 Zygote
Indirect
Development
Example:
 Young Larva
Beetle Development
 Older Larva
Larva has an
intermediate larval
stage.
Larva is an immature
for that exhibits
physical traits that are
different from those of
the adult.
 Pupa
 Adult
VERTEBRATE CHARACTERISTICS pg 659
 Have a backbone
 Includes fishes, amphibians, reptiles, birds &
mammals
 All except fishes spend part or all of their life on land
 In order to adapt to life on land:
 Support of the body
 Conservation of water
1. Vertebrate Segmentation & Support of the
Body
 Yes, they are segmented! Ex. Ribs & vertebrae
 As terrestrial vertebrate evolved from aquatic
vertebrates, their limbs and muscles evolved to give
greater support & mobility.
 Humans: BIPEDAL
 Head is positioned directly over the body
2. Vertebrate Body Coverings
 INTEGUMENT: outer covering
 Fish and amphibians adapted to moist environments
 Terrestrial adapted to dry conditions
1. All bodies are made of water-filled cells. Outer
covering is watertight!
2. In some vertebrates such as amphibians, skin
serves as a respiratory organ.
3. In some vertebrates such as reptile, skin serves
as protection.
4. In some vertebrates such as birds, feathers serve
as insulation.
3. Vertebrate Respiratory & Circulatory Systems
Respiratory
Circulatory
 Aquatic Vertebrates:
 CLOSED circ. System
gases exchange in gills
 Terrestrial Vertebrates:
LUNGS: organs for gas
exchange
with a
MULTICHAMBERED
HEART


Separates oxygenated and
deoxygenated blood
Improves efficiency
4. Vertebrate Digestive & Excretory Systems
Digestive
Excretory
 Digestion occurs in the
 Produce toxic ammonia
GUT: runs from mouth
to anus
(NH3)
 Must expel waste w/o
losing water!
 Kidneys filter the waste
in the blood while
regulating water levels
in the body

In vertberates, the gut is
long and folded to
increase surface area for
nutrient absorption

Human tract: 23 feet long
5. Vertebrate Nervous System
 Highly organized brains
 Fish: mainly used to process sensory information.
 Limited amount is used to decision making
Dogs and such display complex and flexible behavior.
Much of brain is given to decision making.
Brain is large in respect to body size.
6. Reproduction & Development
Reproduction
Development
 Fish & amphibians:
 Zygote nourished by
eggs & sperm are
released directly into
the water where
fertilization takes place
 Reptiles, birds &
mammals: egg &
sperm unite in female
body
egg yolk until hatch.
 Most of development
occurs OUTSIDE of
female’s body.
 Amphibians & fish:
indirect development
 All others: direct dev.