Ch. 28 and 29
what percent of all animals are invertebrates
95%
studies of ____ have shown that pandas are more closely related to bears than to raccoons
DNA
segmentation is a trait of earthworms, not vertebrates (t/f)
F
segments are totally independent of one another (t/f)
F
sponge cells are organized into tissue (t/f)
F
sponges are classified as animals because they're mobile (t/f)
F
____ live in fresh water and attach to rocks by means of sticky secretion produced by an area called the _____
Hydras, basal disk
amoebocytes carry nutrients and remove wastes (t/f)
T
evidence of segmentation in human beings can be seen in the backbone (t/f)
T
segmentation offers evolutionary flexibility because a small change in an existing segment can produce a new type of segment with a different function (t/f)
T
segmented animals are constructed from a series of repeating, similar units called segments (t/f)
T
polyp
a basic kind of cnidarian: tubelike and usually attached to a rock or some other object
medusa
a basic kind of cnidarians: free floating, jelly-like and often umbrella shaped
gastrovascular cavity
a digestive tract with only one opening --> allows for specialization
coelom
a fluid-filled body cavity found between the body wall and the digestive tract (gut)
digestive tract
a gut with two openings that moves food from the mouth to the anus
spongin
a resilient, flexible protein fiber which makes up the "skeletons" of sponges
exoskeleton
a rigid external skeleton (outside the body) that encases the body of an animal
body plan
a term used to describe an animal's shape, symmetry, and internal organization
body cavities:
acoelomates: no body cavity pseudocoelomates: "false" body cavity coelomates: true cavity * evolutionary advancement going down
what is the benefit of not having cell walls
allows mobility that other multicellular organisms don't have
clues to animal relations can be found by comparing the ____ and physiology of living animals
anatomy
parthenogenesis is an ex. of ___ rep.
asexual
Reproduction
asexual--> clones *budding *regeneration *parthenogenesis sexual rep.--> variation *fertilization (internal v. external) *eggs (ovaries) *sperm (testes) *hermaphrodites
sea anemones reproduce ____ by slowly pulling themselves apart into two halves
asexually
sponges can produce
asexually and sexually
symmetry:
asymmetry: irregular shape (SPONGE) radial: body arranged around central axis (SEA ANEMONE) bilateral: distinct right and left halves (HUMANS)
why don't flatworms need a respiratory or circulatory system?
b/c oxygen and carbon dioxide diffuse in and out of the body, and portions of the flatworm's highly branched GVC run close to all the tissues, giving cells access to food
posterior
back (tail end)
spongin used for
bath sponge
in all animals except sponges, the zygote undergoes cell divisions forming a hollow ball of cells called a(n)
blastula
closed circulatory system
blood enriched with O2 and nutrients
open circulatory system
blood supplies tissues with nutrients and oxygen
pseudocoelomates
body cavity is between mesoderm and endoderm
bilateral symmetry
body has a distinct right and left half
asymmetrical
body is irregularly shaped
radial symmetry
body parts arranged around a central axis (can be divided evenly in several places)
ventral
bottom (stomach side)
ganglia
brain-like structure (cluster of neurons which process more info)
obelia live in colonies that form when one polyp reproduces by _____
budding
marine sponges reproduce asexually by _____ and ______
budding and fragmentation
each tiny coral polyp secretes a tough, stone like outer skeleton of _______
calcium carbonate
amoebocytes
cells that move around the mesoglea
bilateral symmetry:
cephalization: gathering of sensory structures in head (AKA brain) dorsal: top (backside) ventral: bottom (stomach side) anterior: front (head region) posterior: back (tail end) lateral: right or left sides
Planarians are members of the _____ Turbellaria, and they are ______
class, free-living
what do collar cells do and how do their flagella help?
collar cells move water through canals (internal) in sponges and flagella rotate to create a current to move the water
____ cells move the sperm cells into the ____ where fertilization occurs
collar, mesoglea
endoskeleton
composed of a hard material such as bone inside an animal
hydrostatic skeleton
consists of water that is contained under pressure in a closed container
three types of sponges
demosponges, silicious, calcareous
Main tissue and organ functions
digestion respiration circulation (open v. closer) nerve impulses (nerve net, ganglia, brain) support (hydrostatic, exoskeleton, endoskeleton) excretion (gets rid of waste)
the layer of cells in the blastula that gives rise to the outer layer of skin, the nervous system and the sense organs
ectoderm
blastulas develop into three distinct cell layers:
ectoderm, endoderm, mesoderm
life cycle of Ascaris
eggs are carried from human waste to soil and when ingested, enter intestine and develop into larvae, which bore through blood vessels in intestine and enter blood stream
clues to animal relations can be found by comparing patterns of development in animal
embryos
digestive system
enables digestion of foods that are larger than individual cells
the layer of cells in the blastula that gives rise to the lining of the digestive tract, respiratory system and many glands
endoderm
digestion in cnidarians begins outside the cell, or _____, and is completed inside the cell, or _______ (in the gastrovascular cavity)
extracellularly, intracellularly
gills
extremely thin projections of tissue rich in blood vessels providing a large surface for gas exchange --> WORKS IN WATER
how do sponges get nutrients?
filter water--> get food molecules from that
choanocytes
flagellated cells that move water through a sponge to trap plankton
tentacles
flexible, fingerlike extensions of cnidarians--> capture and subdue prey
clues to animal relations can be found by looking at the ____ record
fossil
a sponge can rep. by ____ its body
fragmenting
anterior
front (head region)
mesoglea
gel-like substance in which specialized cells are embedded
when living conditions become harsh, some freshwater sponges form _____, clusters of amoebocytes encased in protective coats
gemmules
coelomates
have a true coelom
acoelomates
have no body cavity
calcareous sponges
have spicules composed of calcium carbonate
glass sponges
have spicules made of silica
species of animals that have both testes and ovaries are called
hermaphrodites
three classes of cnidarian
hydrozoa, scyphozoa and anthozoa
animals that live on land usually reproduce by ____ fertilization
internal
oscula
large openings in a sponge's body wall through which water exits
cnidarians: movement
looping or cartwheeling
the layer of cells in the blastula that gives rise to most of the skeletons, muscles and circulatory system
mesoderm
the egg cells reside in the
mesoglea
marine hydrozoans are ___ complex than fresh-water hydrozoans and ____ numerous than are fresh-water hydrozoans
more, more
animals basic characteristics
multicellular eukaryotes no cell wall heterotrophs mobility diploidy sexual rep. with sperm and egg blastula formation (except sponges) tissues (except sponges)
function of spicules
needle like structures that provide support (act like skeleton-- mesh like internal skeleton) and ward of predators (prickly defense-- protection)
a small barbed harpoon within each cnidocyte
nematocyst
neurons
nerve cells (specialized for carrying messages in form of electric impulses
what does the epidermis do?
offers protection
hydra: body openings?
one
endoparasites
parasites inside host
ectoparasites
parasites outside host
sessile
permanently attached to a submerged surface
what does sessile mean?
permanently attached to a submerged surface
a(n) _____ tree shows how animals are related through evolution
phylogenetic
the members of the _______ Platyhelminthes, commonly known as flatworms, exhibit ______ symmetry
phylum, bilateral
some anthozoans reproduce by budding, but others release eggs and sperm into the ocean where the fertilized eggs become _____
planulae (and later develop into polyps)
the sperm and egg of Obelia medusae fuse and produce free-swimming ______ that eventually settle on the ocean bottom and grow into new _____
planulae, polyps
the largest class of cnidarians is the class anthozoa, which exist only as ____
polyps
sperm cells from one sponge enter another sponge through its
pores
another name for sponges
porifera ("pore bearing")
how are gemmules used to reproduce asexually
produced in late fall and the tissue surrounding is dissolves new sponge grows out of genital
tapeworms consist of a head with suckers and a few hooklike structures followed by a string of body sections called
proglottids
what benefit do animals derive from having a coelom?
protects from movement of muscles around; animals can move around without damaging internal organs or interfering with function
cnidarians have what kind of symmetry
radial symmetry
most coral polyps live in colonies called
reefs
excretory system
removes wastes produced by cellular metabolism
lungs
respiratory organs which allow for gas exchange with the environment --> IN AIR
lateral
right or left sides
cephalization
sensory structures and nerves concentrated at the body's anterior
why is pseudocoelom of roundworms an important evolutionary milestone
serves as circulatory and simple gas exchange system
spicules
skeletons made of tiny needles of silica or calcium carbonate that some sponges have
demosponges
sponges that contain spongin (sometimes reinforced with spicules made of silica) third class of sponges
digestion in hydra
starts extracellularly and ends intracellularly
cnidocytes
stinging cells located on tentacles--> subdue prey
respiratory system
takes in oxygen and releases carbon dioxide
flukes hace a thick protective covering of cells called the _____ that helps them avoid being digested by their hosts
tegument
digestion
the breakdown of food in order to get energy and nutrients
excretion
the removal of wastes produced by cellular metabolism
what is the difference between the life cycle of true jellyfish and that of Obelia?
the true jellyfish go through an inconspicuous polyp stage at some point in their life cycle
why are members of the phylum Ctenophora not considered true jellyfish?
they only have a medusa stage and they have no cnidocytes
how do sponges get rid of wastes?
through ameobocytes, which are sponge cells that carry away waste
ostia
tiny openings in a sponge's body wall through which water enters
the cells in cnidarians are arranged into ____, which are specialized cells that work together
tissues
the cells of all animals except sponges are organized into structural and functional units called
tissues
what do all animals have that sponges don't
tissues and blastula formation
why do sponges have skeletons?
to prevent the sponge from collapsing in on itself (support and protection)
dorsal
top (backside)
circulatory system
transports oxygen and nutrients
hydras can sometimes move by _____
tumbling
how many layers of cells are there in marine sponges
two
how do hydra get food?
use stingers to grab and immobilize food before stretching their mouths wide to cover and digest food
heterotrophy
when animals can't make their own food most move from place to find/eat food
sexual rep.
when organisms produce gametes which come into contact with each other to form a newborn organism --> genetic variation
hydra: supporting framework?
yes: mesoglea (gell-like layer between epidermis and gastrodermis)
