clip shape of life: chordata. different classes, which include jawless fishes (e.g., lampreys),...
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ClipShape of Life: Chordata
Different classes, which
includejawless fishes
(e.g., lampreys),
cartilaginous fishes (e.g.,
sharks), bony fishes,
amphibians, reptiles, birds,
and mammals.
Major CharacteristicsDorsal, hollow nerve cord-Spinal cord-Nerves branch off and
connect to organs & muscles
Notochord-Supporting rod that lies just
below the nerve cord
Pharyngeal pouches-in neck or throat regionTail that extends
beyond the anus- at some point in their
livesAnimation
Adult Derivatives of Pharyngeal Pouches
Pouch Adult derivatives
1 Lining of auditory tube and tympanic cavity (middle ear cavity)
2 Largely obliterated, lining of intratonsillar cleft (tonsilar fossa)
3 Inferior parathyroid glands, thymus
4 Superior parathyroid glands, parafollicular cells of thyroid gland
Dealing with the
environment*temperature
*salinity
Thermoregulation1.1. EctothermsEctotherms
– Obtain body heat from the environment
2.2. EndothermsEndotherms– Homeotherm– Generate own body heat- metabolism– High energy requirement– Birds and mammals able to invade colder
areas
3.3. PoikillothermPoikillotherm– Variable body temperature– Most aquatic animals (excluding sea
mammals)- body temp is same as surrounding H2O
Regulating body
temperature
Thermostat: hypothalamus
Four physical processes account for heat gain or loss
• conduction.• convection.• evaporation.• radiation.
Evaporation and convection are the most variable causes of heat loss.
Thermoregulation involves physiological and behavioral adjustments that balance heat gain and
loss:1. Adjusting rate of heat exchange between animal
and its surroundings -Alter amount of blood flowing between body core and skin
-vasoconstriction and vasodilation-altering diameter of blood vessels
-countercurrent heat exchange in extremities
2. Cooling by evaporative heat loss – panting or sweating vasoconstrictionvasodilation
3.Behavioral responses – basking in sun, migration, hibernation
4. Changing the rate of metabolic heat production – only in mammals and birds; heat produced instead of ATP (nonshivering thermogenesis); brown fat, blubber, insulation
Thermoregulation involves physiological and behavioral adjustments that balance heat gain and
loss:
Endothermy(Homeothermy)
• Only birds and mammals• Expensive
– Human – 60% of nutritional intakes goes to providing heat.
– Metabolic rate of mammals is 10x that of a reptile.
• Homotherms were able to invade colder environments.
Temperature conservation can became a problem as animals moved onto land.
Animals can maintain somewhat constant body temp by…– Snake warms itself in the sun and cools off by
hiding in the shade (Ectotherms)– Bees swarm in a hive to raise the temperature– Dogs pant– Elephants flap their ears– Humans shiver
Countercurrent Exchange• The opposite flow of adjacent fluids
that maximizes transfer rates – Heat exchange, gas exchange– Ex:
• Fish use countercurrent exchanges to maximize the extraction of oxygen from water across the membrane of their gills.
• Bird legs in water, fish tails
Water has about 10,000x less O2 than air.
Countercurrent heat exchangers
Gas exchange at the gill surface is enhanced by the opposing flows of water and blood at the gills.
Countercurrent Exchange
-blood flows opposite to the direction in whichH2O passes over gills, maintaining a constant concentration gradient for O2 between the blood and the H2O passing over the gill surface
GillsGills
Also involved in osmoregulation
Fish: Countercurrent
OsmoregulationManagement of the body’s water solute
concentration
• Marine vertebrates– ocean is hypertonic
• H2O constantly lost by osmosis
– They produce little urine & drink large amts of seawater.– Extra salt is actively transported out through the gills.
• Freshwater fish– Water is hypotonic
• H2O constantly diffuses in by osmosis
– Rarely drink– Constantly urinate– Absorb salt through gills
• Terrestrial organisms– Must rid themselves of waste but still retain
water
Osmoregulation
8 Classes
Nonvertebrate Chordates• Two groups do NOT have backbones:
1. Tunicates:-filter feeders, larval form has chordate characteristics, adults do
not2. Lancelets:
-small, fish-like, live on sandy ocean bottom Lancelet
Tunicates
lancelettunicate
•A vertebrate is an animal with a strong, flexible backbone.
•All vertebrates exhibit bilateral symmetry and a true body cavity with an endoskeleton.
•Found in aquatic and terrestrial environments.
Most Chordates are VertebratesKey Features
Endoskeleton:•Support
•Attachment for muscles•Grows with the animal
Chordata Evolution Animation
Key Features
Fishes•Aquatic vertebrates that have:
•paired fins – movement•scales – protection•gills – respiration (gas exchange)
*there are exceptions to all of these because fish are SO varied
3 classes:1. Agnatha (Gnathostomulida) -- jawless2. Chondrichthyes – cartilage skeleton3. Osteichthyes – bony fish
Major Characteristics:•Lateral Line System
•Row of sensitive cells that can detect very small amounts of motion in the water.
•Closed circulatory system•Well developed nervous system and brain•Exchange gases using gills- diffusion•Herbivores, carnivores, parasites, filter feeders, and Detritivores.•Movement- contracting muscles on either side of the backbone•Excreation-NH3 or NH4
+
2 chambered heart• One atrium and one ventricle
– Atrium- chambers that receive blood
– Ventricles-chamber that pump blood out.
• Blood flow to the tissues and back to the heart is aided by swimming motions.
• Blood travels from the heart to the gills, and then directly to the body before returning
simplest type of true heart
Temperature
• Most aquatic animals (excluding sea mammals) are poikilothermspoikilotherms.– having variable body temperature
• Maintain a body temp by seeking a region in the ocean of optimal temp and remaining there.
• Their metabolic processes do generate heat, but it is quickly dissipates into the surrounding water.
Skeleton made of fibers and cartilage
HagfishLack eyes- detect light through sensors on their
bodyFeed on dead and dying fish
Soft skin devoid of scales
•Lampreys •Usually parasitesExternal fertilization. Oviparous ( egg laying)
•Two chambered heart •Gills used for respiration
•No external ears •No eye lids
•Have funnel-like mouths lined with sharp teeth.•In center of mouth is tongue with a tooth like projection.•Attaches to other fish by suction. It tears a hole in the fish and injects a chemical that keeps the blood from clotting. Sucks blood and fluids from its host.
Vertebrate jaws evolved from skeletal supports of the pharyngeal slits
Most sharks are carnivorous
• Prey may be swallowed whole or pieces may be torn from large prey.– Teeth evolved as modified scales.– The digestive tract is proportionately shorter
than in other vertebrates.• A spiral valve, which increases surface area and
slows food movement, is present in the intestine.
•Sharks and Rays•Complete vertebral column, movable jaws, and skeleton with paired fins.
•All of these structures are made up of cartilage
•Whale shark can grow up to 49.5 ft weighing 39,600 pounds.
Clip
• Sharks have streamlined bodies and are swift swimmers.– The tail provides
propulsion.– The dorsal fins serve
as stabilizers.– Pectoral and pelvic
fins produce lift.
•Some buoyancy is provided by large amounts of oil stored in liver, but most must swim continuously to remain in the water column.•Continual swimming also produces water flow through mouth and over gills for gas exchange.
–Some sharks are known to rest on the sea floor and in caves; they use jaw and pharynx muscles to pump water over their gills while resting.
•Water enters the mouth and water passes over the gills where the gases are exchanged.•Sharp sense of smell.
•Also have lateral line lateral line systemsystem.•Internal fertilization
Internal fertilization -Ovoviviparous
• A pair of claspers on the pelvic fins of males transfers sperm into the female reproductive tract.
• Some species are oviparous, some are ovoviviparous, and a few are viviparous.
Viviparous-The embryo develops INSIDE the mother and the mother gives a live birth. Like people.Oviparous-animals that lay eggs, with little or no other embryonic development within the mother. Like chickens.Ovoviviparous-animals develop within eggs that remain within the mother's body up until they hatch or are about to hatch. Like fish.
Most abundant and diverse
Bony endoskeleton, operculum, & swim bladder
Skeleton made of boneMarine & freshwaterSwim Bladder: thin sac that acts as a float. (Filled with gasses) Can be adjusted so that the fish can move to different levels.
Salmon Migration Clip
Most-external fertilization
Lateral line system and a keen sense of smell.
No external ears
No eye lids.
1. Gills for gas exchange• gas exchange is more difficult for aquatic animals with gills than for
terrestrial animals with lungs because water is denser than air and contains less O2 per unit volume
2. Two chambered heart• only vertebrates in which blood flows directly from respiratory
organs to body tissues without first returning to the heart
• Gas exchange occurs by drawing water over the four or five pairs of gills located in chambers covered by an operculum.– Water is drawn into the
mouth, through the pharynx and out between the gills by movement of the operculum and contraction of muscles within the gill chambers.•Allows bony fishes to breath
while stationary.
mudskippersClip
Adaptations in Vertebrates for life on land
Endothermy
Strong Limbs
Muscles Eggs
Lungs
Skin
~365 mya
Amphibian Basics Clip
Major Characteristics:•Lives in water as a larvae and on land as an adult•Moist skin•Breathes with lungs as an adult•Lacks scales and claws•Must return to water to reproduce.•Age of amphibians: 360-286 mya
Clip“Double
Life”
Orders of Amphibians• Order Urodela – salamanders &
newts *long bodies and tails, 4 legs *moist/wet areas
• Order Anura – frogs and toads *all can jump *frogs more closely tied to water than toads
• Order Apoda – caecilians *least known *legless *live in water or burrow in moist soil *some have fish-like scales in their skin
Success on Land:Lungs, stronger
bones in limbs to help support weight
out of water, breastbone to
protect internal organs.
First vertebrates to adapt to life on landYoung can only live in waterUndergo metamorphosis and can live on land Tadpole stage can regenerate lost parts
Frog &Toads
•Smooth skin, no scales, feet are webbed, toes are soft and lack claws
•no external ears: have eardrums or tympanic membranes
Eggs usually Eggs usually laid in water laid in water and fertilized and fertilized
externallyexternallyAmphibian eggs lack a shell & dehydrate quickly in dry air.
In some species, males or females may house eggs on their back, in the mouth, or even in the stomach
Feeding, respiration, circulation, excretion, response, movement, reproduction
• FeedingFeeding: tadpoles are filter feeders or herbivores; frogs are carnivores*have stomach, small intestines, large intestines, cloaca
• RespirationRespiration:: *tadpoles have gills; adults have lungs and use their thin, moist skin (moist surface of mouth).
• ExcretionExcretion:: uric acid -kidneys filter wastes from blood, make urine which is stored in bladder until can be released
Circulation:Circulation: – 3 chambered heart
• 2 atria, 1 ventricle• double-loop circulation
– oxygenated and deoxygenated blood mix in the one ventricle
• Response: *well developed nervous systems, specialized sections of brain*good eyesight*hear with tympanic membrane – transmits vibrations
Feeding, respiration, circulation, excretion, response, movement, reproduction
•Movement: *tadpoles swim – tail for propulsion*adult amphibians walk or jump – legs at
sides of body
Reproduction:*use external fertilization
*Oviparous – lay eggs
*Reproductive
posture is
called
amplexus
Feeding, respiration, circulation, excretion, response, movement, reproduction
EcologyEcology•Food for
other animals
•Some can produce poison - defense
Blue Poison Frog
• Amphibians: In Cold Blood (Sir David Attenborough ) Video
Turtles, crocodilians, Lizards, and Snakes
~300 mya
In Cold Blood Clip
Major Characteristics:•Dry, scaly skin•Scales made of keratin
Helps prevent water lossWith scales or plates
Reptiles:Major Chara. Clip
Major Major Characteristics:Characteristics:•Lungs
Able to breath air
•Terrestrial eggs with several membranes (Oviparous)
Development of amniotic egg• Oviparous: animals that lay eggs
• One of the most important adaptations for life on land.• Does not need water for reproduction
internal fertilization
Development of amniotic egg: egg covered w/a shell that protects the developing embryo from drying outdrying out
Excretion: uric acid
• Some species of lizards and snakes are viviparous, their extraembryonic membranes forming a placenta that enables the embryo to obtain nutrients from its mother.
Egg Layers All turtles All tortoises All crocodilians Some lizards
Iguanas Water dragons Geckos Veiled chameleons Panther chameleons Monitors
Snakes All pythons Kingsnakes Milksnakes Rat snakes Corn snakes
Livebearers Some lizards
Solomon Island skink Blue-tongue skink Shingle-backed skink
Some chameleons Jackson's chameleon
Some snakes All boas All vipers Garter snakes
Limbs, if present, having toes with claws used for climbing, digging, and moving around on land.
•Strong limbs
EctothermEctotherm: animals with a body temperature that is influenced by the environment
*uses behavioral adaptations to absorb solar energy and regulate its body temperature.
*Due to ectothermy, reptiles can survive on less than 10% of the calories required by mammals of comparable size.
Snakes• Jacobson's organ
• Flicking tongue helps transmit odors toward olfactory organs on roof of mouth.
• Most reptiles have a three-chambered heart; although, the ventricle is partially divided.– The partially divided ventricle
reduces mixing of oxygenated and deoxygenated blood.
Intro to Birds Clip
Strong Chests muscles
•Only group adapted to life in the air.•Body covered with feathers
•Modified scales
•Made of the protein keratin and develop in pit in the birds’ skin.
•Two types: Contour (Lift) & Down (Warmth)
•Help birds fly and keep warm•Attract mate•In some species-waterproof
Clip
The bones have a honeycombed internal structure that provides strength while reducing weight
which are that also that power that provide that ensure
have the followingadaptations to flight
Birds
Homologous tofront limbs
in othervertebrates
Providewarmth
Upward anddownward wing
strokes
One-way flowof O2-rich air
O2 distributionto body tissues
Wings Feathers Strong chestmuscles
Efficientrespiratory
system
Efficientcirculatory
system
Tutor Vista Clip: Birds
Air Flow
animation
Endotherms: A constant warm temp. generated
internally by a high metabolic rate.
•Birds have higher metabolic rate than mammals
•Two legs covered with scales
•Modified for specific use- perching, walking, etc.
•Front limbs modified into wings.
Molting: birds sheds their feathers at least once a year (gradual)
Thin hollow bones
-Toothless beak•Birds have many different types of feet and beaks. Modified for the life style of the bird.
Reproduction:•Internal
fertilization•Amniotic egg-
harder shells than reptiles
Digestion:Crop: Storage
Gizzard: Can contain small stones, help
with the mechanical breakdown of food
• Lungs– but have specialized air sacs and breathing
tubes that pull air in when inhale and make sure that oxygenated air is always in the lungs – air only moves in one direction, so yields high metabolic rate (provides energy, and allows birds to breath at high altitudes)
Feeding, respiration, circulation, excretion, response, movement, reproduction
The respiratory system of a bird more efficient than the human respiratory system because the bird’s respiratory system does not mix exhaled air with inhaled air- air only moves in one direction
• Response: well-developed sense organs (great senses of sight and hearing); advanced brain to interpret and respond during headlong flight
• Movement: flight, walk, run, swimming
*bones are light and filled with a scaffolding support
Feeding, respiration, circulation, excretion, response, movement, reproduction
• Circulation: four chambered heart, double loop circulation, that segregates oxygenated blood from unoxygenated blood.– The complete separation of oxygenated and
deoxygenated blood increases the efficiency of oxygen delivery to the cells.
• Excretion: nitrogen waste removed from blood by kidneys, secreted as uric acid crystals (white, pasty droppings, little water)
–uric acid =Allows water conservation
Feeding, respiration, circulation, excretion, response, movement, reproduction
Birds also have a very well developed nervous system.• Acute vision and well-developed visual and coordinating areas of the brainaid in flying.• They show complex behavior especially during breeding season whenelaborate courtship rituals are performed.
• Reproduction: separate sexes, internal fertilization, amniotic eggs
*some parent birds can produce and regurgitate a substance from the crop that is rich in protein and fat to feed offspring – “bird milk”; this is actually just sloughed-off cells from their crop mixed with saliva and mucus
Feeding, respiration, circulation, excretion, response, movement, reproduction
Esophagus
Crop
Liver
GizzardSmallintestine
Cloaca
Pancreas
Air sacKidney
HeartLung
BrainWhen a bird eats,food moves downthe esophagus andis stored in the crop.
1
As digestion continues,the food moves throughthe intestines.
4 Undigested food isexcreted through thecloaca.
5
Large intestine
The muscular wallsof the gizzard squeezethe contents, while small stones grind the food.
3
Moistened food passes to the stomach, a two-part chamber. The first chamber secretes acid and enzymes. The partially digested food moves to the second chamber, the gizzard.
The Anatomy of a Pigeon
2
First chamber of stomach
There are many species of flightless birds: ostrich, penguins
Emus
Rheas
Cassowary
EcologyPollination
Seed dispersalControl insect populationsIndicator of environmental
healthRachel Carson‘s book Silent Spring - pesticides in the food
chain
Humans, Manatees, Elephants, Kangaroos, Apes, Tigers, Dogs
Major Characteristics•Body covered with hair made of keratin-provides insulation•Young nourished in the uterus •Young nourished w/milk from mammary glands•lung-breathing throughout lifetime•Differentiated teeth•Large brains-capable of learning
Intro to mammals Clip
Major Characteristics•Endothermic
•Subcutaneous fat under skin to conserve heat
•Sweat glands to cool body
Feeding:•Carnivores, herbivores, and
omnivores.•Evolution of a strong more
powerful jaw enabled mammals to eat food other
than insects.
Reproduction:•Internal fertilization
Placental Placental ((Eutherian) mammalsmammals: Live birthMonotremesMonotremes:Egg-laying mammals: platypuses and echidnas -After hatching, young suck milk from the fur of the mother who lacks nipples.
MarsupialsMarsupials:Pouched mammals: Kangaroo, koalas, opossum
**Young are born in an early stage of development and completes its development while nursing.
Australian monotremes and marsupials: echidna (top left), marsupial mouse (lower left), sugar glider (right)
Monotremes:Egg-laying mammals
• Excretion-Urea– less toxic than NH3 and requires less
H2O
– NH3 converted to urea in liver
• Kidneys filter blood, add water to make urine.
Form and Function of Mammals• Jaws and teeth allow for diverse diet• Highly developed brains with good
senses – taste, sight (color vision), smell, hearing (ears with chambers), touch
• Movement varied: run, walk, climb, burrow, hop, pounce, swing, fly, leap, and swim
Circulation
• Double-loop circulation, 4 chambered heart
• two atria and two ventricles• deoxygenated and oxygenated
bloods are not mixed
Pig
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