animal comparative anatomy

Question 1

grasshoppers have holes along their abdomen called spiracles. Functions?

Answer 1

There are muscles around the spiracle so that they can open or close it. Close it to prevent water loss because they live in dry climates.

Question 2

grasshoppers have tubes that are supported by chitin ring called tracheae. Function of chitin rings?

Answer 2

They prevent the trachea from collapsing, so they get continuous air flow. It’s analogous to our trachea that is made of cartilage instead of chitin.

Question 3

have dead-end, smaller tubules that have no chitin rings called tracheoles. Function?

Answer 3

They are small trachea. Direct air flow to each and every cell. Gas exhange happens in tips of the trachioles. Analagous to alveoili. Branched so it has more surface area. No chitin rings surrounding it so its easier to diffuse through. Less distance. O2 needs to dissolve before it gets into the cells.

Question 4

have air sacs. Function?

Answer 4

Not involved in gas exchange but can expand and compress. Analagous to diaphragm in us. Every time grasshopers moves sacks are getting compressed and decompressed, out diaphram is devoted only to helping us breathe

When not moving air and oxygen get in by simple diffusion. 20% of air we breathe is oxygen. Milions of years ago there was 35% oxygen in the air. Animals that used oxygen diffusion were massive. Dragon fly no all small, because can’t get as much oxy to cells, so it stays small

Question 5

How is the respiratory system of birds designed to allow for unidirectional, continuous flow of fresh air?

Answer 5

Their lungs are permenantly inflated and don’t change shape. Helps with unidirectional flow of air, no diaphragm because job of diaphragm is being done by air sacs. Gas echange happens in parabronchi in air capillaries.

What is analagous to avleoli in us in birds it’s air cappilies. Analgagous to tradchioles

Question 6

Where does gas exchange occur?

Answer 6

Air sac, birds have 8=9 airsacks. Posterior air sack are behing the lungs, anteriro are infront of the lungs. Air goes in a uniderectional flow in lungs. The lungs going into lungs of birds is going to be fresh air, no stale air left behing. Lungs are open ended, so no back tracking of the air. Air has to back track after alveoli to outside of body.

They don’t have any alveoli, only open ended ducts called parabronchi. These are parallel air tubes.

Birds used to die in train stations and noticed that tar from burning of the coal, so bottom end of lungs was blocked.

Question 7

Pharynx is a common passageway for air and food. What prevents food from entering the lungs of mammals and birds?

Answer 7

Rat was epiglottis, made of elastic cartilage. When you swallow it goes backwards and downwards. Acts like lid and cover s trachea. Analagous is gill rakers.

Birds have no epiglottis because it allows for continous unidirectional flow of fresh air thorugh the lungs. Epiglottis would get in the way.

Question 8

Larynx is the voice box. How do mammals and birds produce sounds?

Answer 8

Middle oppening is the glottis side is the vocal chords. photo

“voice bos” vocal cords here. Space in the middle called glottis. Muscles in vocal cord allow you to talk in high or low pitch by controlling tension. Birds have 6 pairs of vocal chords. They have individual muscles that control the tension to give rise to different sounds. Have way more control over membranous folds. Can use trachea as echoing chamber. Their trachea is lower down

Question 9

Trachea allows for continuous air flow. Compare the trachea of mammals, birds and insects.

Answer 9

Trachea of mammals doesn’t fully going around so the back of it is the esophagus. This is so that you can swallow large portions of food. If cartilage went all around, there would be no expansion for peristalsis to take place.

Trachea of birds goes all the way around. In birds it’s made of cartilage. In insects the trachea is made of chitin. Can’t strangle a bird of insect, but can strangle humans. Not necessarily homologous because composition and structure is different

Question 10

bronchi vs bronchioles vs alveoli

Answer 10

bronchi carry air to each lung. KNOW SLIDE OF ALVEOLI. alveoli are sacs, huge SE for gas exchange

bronchioles carry air to alveoli. Alveoli are the dead - end sac where gas exchange occurs

Question 11

Diaphragm ventilates the lungs. How?

Answer 11

Wall that goes across the bottom of your chest. Muscular wall that seperates your chest from your abdomen. Every time you inhale, diaphram has to contract. From dome shaped structure to flat structure. Your lungs will expand, dropping the pressure and sucking the air in. All during inhaling Exhaling: diaphram goes upwards, lungs become compressed, will increase pressure in your lings and force all the air out

Operculum in fish is analagous to operculum in mammals

Question 12

Why is breathing in mammals less efficient than in birds?

Answer 12

Mammals have air left over in lungs, but birds always have fresh air because their lungs are not dead ends. Mammalian lungs never completely relax.

Fresh air mixes with stale air. We have smaller gradient for gas exchange. Birds parabronchi called air capillaries. Have 21% oxy because breathe only fresh air. We only have 16% oxy

When we exhale, we put a momentary pause on gas exchange. Never momentary pause in bird gas exchange process.

Question 13

Arthropod’s digestive tract is soaked in blood. Explain

Answer 13

They have no blood vessels; therefore open circulatory system. Blood leaves blood vessels and enters the coelom (body cavity)

starts in the mouth, ends in anus; has mouth cavity with short esophagus. Their esophagus expands to store vegetation.

Question 14

Crop is an expansion of the esophagus. Function?

Answer 14

stores vegetation and breaks it down

Question 15

Gastric ceca are pouches extending from the stomach. Function?

Answer 15

Stomach has outpocketings. Total of 12 outpocketing coming off the stomach called gastric ceca. Increase surface area for absorption of nutrients. IF vegetation goes into pouch, spends lots of time in there because needs to backtrack into stomach. Longer food is inside the pouch, more chemical breakdown and more absorption of nutrients

Question 16

Malpighian tubules are dead end ducts. Function?

Answer 16

Stomach has outpocketings. Total of 12 outpocketing coming off the stomach called gastric ceca. Increase surface area for absorption of nutrients. IF vegetation goes into pouch, spends lots of time in there because needs to backtrack into stomach. Longer food is inside the pouch, more chemical breakdown and more absorption of nutrients

Question 17

Malpighian tubules are dead end ducts. Function?

Answer 17

Excess wastes and salts in blood go into tubeules, gets rid of liquid waste. Water gets reabsorbed, also water, salt and sugar. Reabsirption happens in intestines. Kindeys and intestines work to only produce 1 waste.

Question 18

Rectum is an expansion of the intestines. Function?

Answer 18

Straight portion of the intestines. After through rectum semi, solid waste material. Waste is called uric acid.

Question 19

Proventriculus is an oval chamber. Function?

Answer 19

“front chamber” found in front of gizzard. Produces enzymes to chemically breakdown food. Also produces HCL needed to activate ezymes and break down outer part of seed. Produces way more HCL than we do. The pH is 1.

Question 20

Gizzard is a muscular chamber lined with keratin. Function?

Answer 20

This is wehere mechanical / physical breakdown of food occurs. Has 4 layers of mucsles and is filled with stones tht are also used in physical breakdown. Stones are needed to break down seeds, anything soft wouldn’t work. Stones turn into sand over time and are then excreted. So have to swallow stones

Have keratin lining to prvent stones from damaging tissue. Like having teeth in your stomach. Gizzard analagous to our teeth. The other three are analogous to mouth (I think)
ostriches stick their head in the sand to eat stones

Question 21

Colic ceca are tubular dead-end pouches. Function?

Answer 21

Are two outpocketings. Two pouches that don’t lead anywhere ar colic ceca. Stores bacteria that carry out fermentation and break down vegetatiion. Produce cellulase. Ath the end have glucose which can then be used to feed the bird. Has to backtrack to get out, so more opportunity to absorb glucose. Greater chemical breakdown and greater absoption

Fish have lots of pyloric cecae. Birds don’t have a lot of colic ceca.

Birds have 2 cecae for balance when flying.

Question 22

Why is the rat considered to be
an herbivore based on the
structure of their digestive tract?

Answer 22

Rat eats eveything it comes across, but the ancestors of rats were herbivores.

Rats don’t have canines, but have incisors that are designed to cut into vegetation.

The molars “grinding”: were broad and wide, had ridges that were perfect for grinding vegeation. Molars of carnivores are like scissors.

The cecum of rat is twice as big as the stomach. Stores bacteria that breaks down cellulose. Our appendix had a large cecum.

Rats don’t have a gallbladder. (stores bile to breakdown fats), reabsorbs water away from bile. Makes bile more concentratied.

Bile salts suspend fat droplets –> emulsification., then lipase can come in and chemically break down the food. Bile salts physically breakdown food, not chemically.