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Biology 102
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233
Biology
Undergraduate 1
04/29/2010

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Term
response of an organism to a stimulus; may be genetic or environmentally determined
Definition
behavior
Term
study of how behaviors affect survival and reproduction
Definition
behavioral ecology
Term
study of animal behavior
Definition
ethology
Term
day length affects normal release of the pituitary; robin flies south in fall; Explanation of an animal's behavior based on trigger stimuli and internal mechanisms
Definition
proximate cause
Term
how does behavior affect reproductive success - flies south to stay warm; Explanation of an animal's behavior based on evolution. Requires that behavioral traits, like physical ones, are genetically heritable, and then explains behavior using an explanation of why this specific behavioral trait was favored by evolutionary mechanisms such as natural selection.
Definition
ultimate cause
Term
experiment for genetically determined behaviors
Definition
  • in honeybees
  • study done by W.C. Rothenbuhler in 1964
  • two groups of bees: hygienic (detect and remove diseased larvae from the nest - uncap wax cells and discard dead larvae) and nonhygienic (don't do this)
  • one gene (u) for uncapping and another (r) for larval removal
  • double recessive - hygienic
  • double dominant - nonhygienic
  • hybrids - nonhygienic
Term
genetically determined behaviors that are turned on by a stimulus and go to completion
Definition
fixed action patterns
Term
in many cases animals can ___(1)___ their behaviors - there can be ___(2)___ involved
Definition
  1. modify
  2. learning
Term
a type of learning that involves an association between a stimulus and a response
Definition
associative learning
Term
types of associate learning
Definition
  1. classical conditioning
  2. operant conditioning
Term
concious problem solving
Definition
cognitive learning
Term
learning that occurs during certain critical periods
Definition
imprinting
Term
movement that is nondirectional in response to a stimulus; pill bug
Definition
kinesis
Term
movement of a pill bug
Definition
moves slow in moist areas and moves fast in dry areas
Term
directional movement in response to a stimulus; moth, sea turtles
Definition
taxis
Term
movement of moths
Definition
move towards light
Term
movement of sea turtles
Definition
hatchlings move towards light which moves them towards the ocean
Term
animals can use ___(1)___ and ___(2)___ in movement
Definition
  1. memory
  2. landmark
Term
study of digger wasps by Tim Bergen
Definition
  • use landmarks such as pine cones to find their nest
  • sight not smell
  • genetic component and a learning component
Term
long distance movement; in birds, wildebeasts, whales, monarch butterflies; can happen over several generations; strong genetic component
Definition
migration
Term
methods of migration
Definition
  1. piloting
  2. orientation
  3. navigation
Term
in whales and dolphins; moving from landmark to landmark
Definition
piloting
Term
you follow some sort of compass reading, know what direction to go
Definition
orientation
Term
orientation, but adjustments; one example is an imprint of star patterns or the angle of the sun; can use magnetism
Definition
navigation
Term
young are shown to use ___(1)___ but as adults use ___(2)___
Definition
  1. orientation
  2. navigation
Term
why is sex ratio 50:50?
Definition
if there were 20 females for every one male, male would be very successful in leaving his genes in next generation - fertilizes all 20 - 20 families and each female has 1 family -> selection pressure for male individuals -> when males are more apparent then die out -> need 50:50 ratio
Term
types of mating systems
Definition
  1. monogamy
  2. polygamy
  3. polygyny
  4. polyandry
  5. sexual selections - intersexual and intrasexual
Term
one individual mates with one mate per breeding system
Definition
monogamy
Term
one individual mates with more that one mate per bredding season
Definition
polygamy
Term
male mates with many females, male doesn't provide any parental care
Definition
polygyny
Term
female mates with several males, not common but male takes over parental duty
Definition
polyandry
Term
mating in sandpiper
Definition
female has a territory - male comes and impregnates -> she lays eggs -> he broods eggs and she finds other males to mate with
Term
intersexual selection
Definition
usually female chooses male - based on nuptual gifts, male display (courtship), physical fitness, potential parent skills
Term
males gives female something to eat in return for sex
Definition
nuptual gifts
Term
intrasexual selections
Definition
members of one sex compete with each other for mates; apparent in elephant seals and humans
Term
any materials taken in by the body for growth, maintenance, and repair
Definition
nutrient
Term
chemical breakdown of foods to smaller forms which maybe absorbed into the body
Definition
digestion
Term
passage of nutrients from GI tract in the body (blood)
Definition
absorption
Term
what do you obtain from nutrients?
Definition
  1. energy for ATP
  2. some nutrients used as building blocks
  3. vitamins and minerals are used as coenzymes and cofactors in the body - help enzymes
Term
nutrients
Definition
  1. carbohydrates
  2. lipids
  3. proteins
  4. vitamins
  5. minerals
  6. water
Term
sugars or starches used for energy
Definition
carbohydrates
Term
lipids
Definition
  • fats
  • water insoluble nutrients
  • main type - triglyceride
  • hormones
  • plasma membrane
  • eicosonoids
Term
proteins
Definition
  • long chains of amino acids
  • energy - rather not, used for building blocks of enzymes for daily functions
Term
small signalling molecules, in inflamatory response
Definition
eicosonoids
Term
redness and swelling, temperature control, aspirin interferes with this
Definition
inflamatory response
Term
nutrients that can't be made in effective amounts by the body, have to be obtained by diet; 8 amino acids
Definition
essential nutrients
Term
has the ability to dissolve in fat
Definition
fat soluble
Term
has the ability to dissolve in water
Definition
water soluble
Term
vitamin c difficiency
Definition
scurvey
Term
iron difficiency
Definition
anemia
Term
animals that eat plants
Definition
herbivors
Term
animals that eat meat
Definition
carnivores
Term
animals that eat both plants and animals
Definition
omnivores
Term
feedings strategies
Definition
  • anemonies just catch food as it goes by
  • filter feeding - clams and whales - filter food from water
  • carnivore - predators and scavengers
  • herbivore - grazers, ruminants, frugivores
  • omnivore - both plants and animals
  • fluid feeders - parasites, nectar eating birds
Term
feeding intracellularly
Definition
cell will engulf materials into a vacuole and then digestive enzymes will digest the food
Term
feeding extracellularly
Definition
cells will release digestive enzymes and digest food and then will absorb digestive materials - usually done in a digestive tract
Term
digestive system with one opeing
Definition
incomplete
Term
digestive system with two openings
Definition
complete
Term
digestive system in vertebrates
Definition
  • gastrointestinal tract - GI tract
  • tube called alimentary canal and various accessory organs - salivary glands, pancreas, gall bladder, liver
Term
Food processing in the mouth
Definition
  • teeth - chewing, breaking up larger pieces into smaller pieces
  • salivary glands add saliva to food
Term
teeth of the carnivore
Definition
have all sharp teeth and used for cutting, stomach will grind up food
Term
teeth of an herbivore
Definition
flat molars - chewing rotational and you grind up plant material on the molars
Term
functions of saliva
Definition
  • moistens and lubricates the food for swallowing
  • salivary amylase begins the break down of starch to sugars
  • dissolves food into water to allow taste buds to work
  • acts to break down bacteria due to lyzozymes
Term
swallowing
Definition
moves the food in the pharynx and then the esophagus which then transports it to the stomach
Term
food is moved through the GI tract by ______
Definition
peristalsis - a way of contraction done in the tube - all done automatically
Term
stomach
Definition
  • food stored temporarily
  • add HCl to denature proteins
  • add pepsin to break down proteins
Term
modifications of the esophagus and stomach
Definition
  • birds - enlargement of esophagus called a crop - liquid is added to moisten and soften food; have a two part stomach - proventriculus - glandular region where you add enzymes to break up proteins; gizzards - muscular organ for grinding up seeds; swallow pebbles and they stay in the crop - used to grind the food
  • luminants (cows) have a complex stomach for mixing cellulose with bacteria; food is taken into the rumen where it is mixed with bacteria; food is regurgitated later and rechewed as cud -> reswallowed where it is then passed to the omasum -> begin to reclaim sugars bacteria broken down -> normal stomach called abomasum
Term
small intestine
Definition
  • major site of digestion
  • pancreas, liver, and gall bladder add secreations to food at beginning of small intestine
  • surface area - villi and microvilli
  • as enzymes break up large molecules to small become small enough to become absorbed - main function of small intestine
  • by the time you get to the end, you've absorbed all the good stuff
  • absorption is done by simple diffusion, but mostly facillitated diffusion or active transport
Term
pancreatic juice
Definition
  • bicarbonate (HCO3-) - neutralizes stomach acid
  • amylase - breaks up carbohydrates
  • proteases - break down proteins to amino acids
  • lipases - break down lipids
  • bile - emulsifies fat
Term
finger-like projections in the small inestine
Definition
villi
Term
in cells lining villi, finger-like processes, have enzymes on their surface
Definition
microvilli
Term
modifications for small intestine
Definition
rabbits - add bacteria to the waste materials coming into the large intestine at the caecum - filled with bacteria; eat their fecal pellets and pass it through again but this thime with bacteria added
Term
liver
Definition
screates bile for break down of fats
Term
process of breaking fat from big globules into smaller pieces
Definition
emulsification
Term
control of blood sugar levels
Definition
  • when blood glucose levels go up the pancreas releases insulin -> activates glucose transporters on cell surfaces and they take glucose out of the blood
  • if blood sugar levels drop, the pancreas releases glucogen -> 1) break down glycogen to glucose and throw in the blood 2) gluconeogenesis - make glucose out of amino acids and glycerol 3) you can make ketone bodies for energy
Term
lack of adequate insulin
Definition
diabetes
Term
lack of adequate glycogen
Definition
hypoglycemia
Term
energy expenditure - how do you measure energy?
Definition
  • calorie
  • Calorie
  • direct calorimetry
  • indrect calorimetry
Term
the amount of energy needed to heat 1 mL of water 1 degree centigrade
Definition
calorie
Term
kilocalorie; amount of energy needed to heat 1 L of water 1 degree centigrade
Definition
Calorie
Term
measure of body heat produced per time - measure of basal metabolic rate
Definition
direct calorimetry
Term
measuring oxygen usuage to get a basal metabolic rate
Definition
indirect calorimetry
Term
rate measured at rest; basic amount of energy needed for basic processes
Definition
basal metabolic rate
Term
get most of their heat from environment
Definition
ectotherms
Term
metabolic rate with no activity at usual temperature
Definition
standard metabolic rate
Term
if you use your ___(1)___ you ___(2)___ your energy expenditure greatly
Definition
  1. muscles
  2. increase
Term
energy needed to digest your food - 10% - usually ignored
Definition
food induced thermogenesis
Term
metabolic rate is relatred to body size ->
Definition
the bigger you are, the slower your metabolic rate -> due to decrease in surface area to volume ratio; small organisms need to eat to maintain body temp and produce energy
Term
organisms that produce their own body heat
Definition
endotherms
Term
organisms that can change their own body temp
Definition
heterotherms
Term
organisms that can keep a constant body temperature; normally have a higher metabolic rate
Definition
homeotherms
Term
how do organisms give off heat?
Definition
  1. radiation
  2. conduction
  3. convection
  4. evaporation
Term
emit heat as electromagnetic waves - infrared
Definition
radiation
Term
passage of heat from a body by contact
Definition
conduction
Term
you heat air or water surrounding the body and it is carried away
Definition
convection
Term
sweat or pant so water can turn into vapor and this is an exothermic reaction
Definition
evaporation
Term
Welwitschia and Ephedra both lack a gametophyte phase in the life cycle
Definition
true
Term
Rhizaria include
Definition
radiolarians and foraminiferans
Term
the organism that causes botulism is able to occur in foods that have been improperly heated due to
Definition
endospore formation
Term
cyanobacteria are thought to be the ancestors of
Definition
chloroplasts
Term
bacteria lack
Definition
histones
Term
Rhodophytes, Chlorophytes, and Plants are all considered to be in the supergroup
Definition
Archaeplastida
Term
one characteristic of the bryophytes is that they all
Definition
lack vascular tissue
Term
spiral shpaed bacteria which are flexible are known as
Definition
spirochaetes
Term
in the bryophytes eggs are produced
Definition
in an archegonia
Term
the stamen are believed to have evolved from primitive
Definition
leaves
Term
Diazotrophs
Definition
are bacteria that are able to carry out nitrogen fixation
Term
Bacteria usually reproduce by binary fission.
Definition
true
Term
order of taxa
Definition
domain -> kingdom -> phylum -> class -> order -> family -> genus -> species
Term
some bacteria, including cyanobacteria, are able to move up and down in the water in response to sugar content of the cell due to
Definition
gas vesicles
Term
the protist group the is believed to be the ancestor of the plants is the
Definition
Charophyseans
Term
one characteristic feature of the angiosperms is
Definition
endosperm
Term
sleeping sickness (Trypanosoma) is caused by a protist in the phylum
Definition
Kinetoplastea
Term
viruses can transfer DNA between bacterial cells by
Definition
transduction
Term
the addition of oxygen to the atmosphere is thought to have due to
Definition
cyanobacteria
Term
lycophytes and pterophytes are referred to as
Definition
seedless vascular plants
Term
ciliates usually exchange genetic material by
Definition
conjugation
Term
leaf-like structures were first seen in the
Definition
lycophytes
Term
conifers can prevent air bubbles from spreading from one tracheid to another by
Definition
tori
Term
the cell nucleus is now believed to have formed from the endosymbiosis of
Definition
archea
Term
most antibiotics act to slow or stop bacterial growth by
Definition
interfering with peptidoglycan production
Term
which plant type was shown to have cyanophytes in its small emergent roots that aid in nitrogen fixation?
Definition
cycads
Term
angiosperms with a single seed leaf are
Definition
monocots
Term
one difference between bacteria and archaea is tha archaea
Definition
have a plasma membrane which is ester linked
Term
a phylogenetic tree which shows birds and reptiles as belonging to separate clades is said to be
Definition
paraphyletic
Term
a supergroup of protists characterized by a feeding groove is known as the
Definition
Excavata
Term
Plants are actually classified in a supergroup with several types of protists. That supergroup is called
Definition
Archeoplastida
Term
sugars are transported in vascular plants by
Definition
phloem
Term
when two or more species influence each other's evolutionary pathway the result is
Definition
coevolution
Term
characteris seen in the euglenozoa include
Definition
  • protein strips near the surface of the cell
  • carbohydrate storage particles called paramylon
  • an eyespot
  • disc shaped mitochondrial cristae
Term
protist supergroup that is considered to be the ancestor of the animals is the
Definition
Opistkonta
Term
bacterial cells are different from other cells in that they are enclosed within a
Definition
peptidoglycan cell wall
Term
Heliobacter pylori is an example of a(n)
Definition
proteobacteria
Term
in the angiosperms an ovary will eventually develop into a
Definition
fruit
Term
photosynthetic protists which swim or float are known as
Definition
phytoplankton
Term
bacteria are able to come together to produce a biofim by a process known as
Definition
quorum sensing
Term
characteristic feature of the fungi is
Definition
chitonous cell wall
Term
colloblasts are found in the
Definition
ctneophores
Term
torsion occurs in the
Definition
gastropoda
Term
How are the three domains of life similar to each other?
Definition
They each use a similar genetic code, they use DNA as their genetic code, they use similar metabolic pathways (ex: glycolysis), they all use tRNA and mRNA, and all their codons code for the same amino acids.
Term
Compare and contrast the cell wall structure of a gram negative and a gram positive bacteria.
Definition
Both have peptidoglycan.  The gram negative has an extra phosholipid bilayer on top of the thin layer of peptidoglycan.  The gram positive only has a thick layer of peptidoglycan.
Term
Describe the structure of a bacterial flagellum.
Definition
The flagellum's structure is mostly composed of solid protein.  The flagellum is connected to the plasma membrane via a "hook."  This hook is attached to a "motor" on the flagellum.  A gradient of H+ is created and as the H+ flow back through the membrane, the motor will spin causing the flagellum to spin in a circular motion.
Term
Describe primary, secondary, and tertiary endosymbiosis in the Protista.
Definition
  • primary - archeoplastidia have plastids for photosynthesis
  • secondary - have plastids with 3 membranes around them in stremopila
  • tertiary - in alveolata
Term
Discuss trends in the relative importance of sporophyte and gametophyte generations in plants.
Definition
The more recent plants lack a gametophyte stage (in gnetophytes and angiosperms).  In the older plants, the sporophyte is completely dependent on the gametophyte (in bryophytes).
Term
Nautiloids can move up or down in the water using
Definition
a siphuncle.
Term
Spicules are found in
Definition
porifera.
Term
An infective stage of a trematode is a
Definition
cecaria.
Term
Platyhelminthes are acoelomate.
Definition
True
Term
Asexual reproduction of lichens involves hyphae wrapped around some algal cells to produce a dispersive stage known as a
Definition
soredia.
Term
Square jellyfish with four tentacles and four lensed eyes are
Definition
cubozoa.
Term
The intermediate host of a trematode is usually a
Definition
snail
Term
A mollusc with with a lung-like mantle cavity is a
Definition
pulmonata
Term
The gut of the oligochaetes is unusual in that it has a
Definition
trophosome
Term
The ectoparasitic annelids are the
Definition
Hirudinea
Term
An extracellular matrix of collagen is characterisic of
Definition
animals
Term
Fungi with flagellated cells are known as
Definition
chytrids
Term
Corals are able to grow and produce in huge areas with little food in the water due to
Definition
symbiotic algae
Term
The group that exhibits detorsion is the
Definition
opistobranchia
Term
Hirudinea can suck blood without it clotting because
Definition
its saliva contains hirudin
Term
Bivalves have a characteristic structure in their gut called a
Definition
crystalline style
Term
Cleavage is indeterminate in the
Definition
deuterostome
Term
Clamp connections are characteristics of the
Definition
basideomycetes
Term
The characteristic structure of a rotifer is a
Definition
corona
Term
The mollusc class with branchiae found in grooves on each side of the body is the
Definition
polyplacophora
Term
Clams found at deep sea vents are able to grow large due to
Definition
symbiotic bacteria
Term
Bryozoans live in a
Definition
zooecium
Term
The coelom in molluscs is reduced to make up only the mantle cavity
Definition
false
Term
A zygosporangium is found in the
Definition
zygomycetes
Term
An association between fungal hyphae and plant roots is referred to as
Definition
microhizae
Term
Lophophorates that have a dorsal/ventral shell are known as
Definition
branchiopods
Term
Polychaetes have
Definition
setae
Term
Hox genes are involved in
Definition
development of body segments
Term
A mutualistic relationship between a fungus and an algae is known as a
Definition
lichen
Term
A diploblastic animal lacks
Definition
a mesoderm
Term
A cnidarian which lacks a medusoid stage is an
Definition
anthozoa
Term
The class of molluscs that has a closed circulatory system is the
Definition
cephalopoda
Term
Sponges feed using cells called
Definition
choanocytes
Term
Schizocoelous coelom formation is seen in the
Definition
protostomes
Term
All cephalopods lack an external shell.
Definition
False
Term
Free living platyhelminthes belong to the class
Definition
turbellaria
Term
A strobila is a reproductive stage in the
Definition
scyphozoan
Term
Explain how growth of hyphae occurs in the fungi.
Definition
Sugar is put into the hyphae cell and water will flow in due to osmosis.  This creates pressure causing the cell wall to weaken.  Vacuoles will then build up extending the cell wall.  This occurs in the tip of the hyphae.
Term
What is the difference between a pseudocoelom and a true coelom?
Definition
A pseudocoelom is not lined by mesoderm and a true coelom is.
Term
Compare an asconoid, a syconoid, and a leukonoid sponge.
Definition
[image]
Term
Briefly describe torsion.   What specific group of animals exhibits torsion?
Definition
Torsion occurs in the larval stage when the rear of the shell turns back up upon itself and thus creates a cavity.  This is apparent in the gastropoda.
Term
What are the three advantages of segmentation in the annelid?
Definition
  • segments can be specialized
  • all the necessary organs are found in each segment so if one segment fails, there are others to carry on
  • helps with movement of the organism
Term
Based on the description given in class, describe how feeding occurs in the bivalvia.
Definition
mucus with food is moved by cilia along branchi to mouth -> mouth -> gelatinous rod (crystalline style) on side wall of stomach - spins/rotates -> winds mucus around it pulling material into stomach - tip grinds against a hard structure and it breaks down into an enzyme-filled material that mixes with the food -> food broken down and absorbed, waste materials go out intestine to the anus opening to the mantle cavity
Term
Opposable thumbs are characteristic of the
Definition
primates
Term
A unique characteristic of the echinoidea is
Definition
an Aristotle's lantern
Term
Unlike the insects the crustacean have
Definition
two pair of antennae
Term
The class of animals with the greatest number of species is the
Definition
insects
Term
The hemichordates are
Definition
invertebrate chordates
Term
A three chambered heart is seen in the
Definition
"reptiles"
Term
Asteroidea
Definition
can evert their stomach to feed
Term
The cephaloaspidomorphs (sea lampreys) lack
Definition
jaws
Term
Deuterostomes have indeterminate cleavage
Definition
True
Term
Malphigian tubules are found in insects and are used in
Definition
excretion of wastes
Term
About the only animals that concentrate vanadium are the
Definition
urochordata
Term
Ommatidia are found in
Definition
the compound eye of arthropods
Term
Members of the Class Chilopoda (centipedes) are predators.
Definition
True
Term
Urochordata are considered chordates because
Definition
their larvae has all the chordate characters
Term
A naupilus larvae is found in most
Definition
crustaceans
Term
Phyla of Ecdysozoa
Definition
Nematoda and Arthropoda
Term
The chondrichthyes maintain their buoyancy by
Definition
an oil filled liver
Term
According to the book the following are characteristic of Aves (birds)
Definition
air sacs, feathers, a lightweight skeleton, and reduced organs
Term
The class of echinoderm that has an endoskeleton on only small spicules is the
Definition
holothuroidea
Term
Many groups of fish are able to sense water pressure changes with their
Definition
lateral line system
Term
A scorpion is a type of
Definition
arachnid and athropod
Term
Elephantiasis of humans is caused by a
Definition
nematode
Term
An animal with a cephalothorax and an abdomen plus 6 pairs of appendages is an
Definition
arachnid
Term
A defense mechanism of the myxini (hagfish) is
Definition
mucus production
Term
Encrusting organisms are not able to settle on a starfish due to
Definition
pedicellaria
Term
Echinoderms lack a kidney and can only live in fresh water.
Definition
False
Term
One limitation of the amphibians is
Definition
they must reproduce in water
Term
Sea urchins and sand dollars are
Definition
echinoids
Term
Buccal breathing is characteristic of the
Definition
amphibians
Term
Nematodes are unusual in that they have
Definition
an exoskeleton made of collagen
Term
In order to avoid predators the holothuria
Definition
throw out (self eviscerate) their internal organs
Term
The prototheria
Definition
lay eggs
Term
All of the following are found in echinoderms except for
Definition
a radula
Term
The following are true of insects
Definition
they have 3 pairs of walkings legs, they have 2 pairs of wings, they have a head thorax and abdomen, and they have a single pair of antenna
Term
The dipnoi are
Definition
lung fish
Term
The eggs of vertebrates other than the fish and amphibians have
Definition
an amniotic sac that surrounds the embryo
Term
The difference between complete and incomplete metamorphosis is that in complete metamorphosis
Definition
there is a larval stage followed by pupation
Term
A flexible rod for swimming, seen in all chordates is the
Definition
notochord
Term
What class of animal is a craniate but not a vertebrate?
Definition
myxini
Term
All of the following are true of chordates
Definition
they have a notocord, they have a dorsal hollow nerve cord, they have a post anal tail, they have pharyngeal gill slits
Term
Discuss the characteristics of arthropods which allowed them to live on dry land.
Definition
  • exoskeleton made of chiton - prevented drying out
  • developed book lungs for breathing
  • malphigian tubules to filter out waste
Term
Describe the body morphology of an insect.
Definition
  • holes in their side called spicules that lead to tracheal tubes
  • head, thorax, and abdomen
  • 3 walking legs and 2 wings
  • top wings are flaps of cuticle
  • chitin exoskeleton
  • pair of antennae, mandibles, maxillae, and labrum
Term
Describe the water vascular system of echinoderms including the tube feet.
Definition
  • set of tubings that bring in sea water and allow tube feet to move
  • madraporite brings in the water
  • ring canal with radial canals that extend into arms
  • ampulla - squeeze and tube feet extend, if you pull the muscle the end of the tube feet become like a suction cup
Term
What characteristics lead us to believe that the Urochordates are chordates?
Definition
  • larval form looks like a tadpole
  • notocord
  • dorsal hallow nerve cord
  • pharyngeal gill slits
  • post anal tail
Term
Based on the fossil record, how did jaws develop in the vertebrates?
Definition
Jaws developed from gill arches which are structures between gill slits.
Term
Describe the structure of an amniotic egg.  What advantages did it provide to the higher vertebrates?
Definition

The amniotic egg has 4 membranes:

  1. chorion - outer covering that is porous for gas exchange
  2. amniotic sac - fluid that surrounds the embryo for protection
  3. yolk sac - food supply
  4. allantois - waste storage

This allowed for eggs to be laid on land and for even high vertebrantes allowed the egg to stay inside the mom.  Also, allowed for internal fertilization.

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