vertebrates

Question 1

what are four features all chordates have in common at some stage of development?

Answer 1

1. notochord
2. pharyngeal slits
3. hollow, dorsal nerve chord
4. post anal tail

Question 2

describe the amphioxus

Answer 2

Amphioxus means sharp at both ends

A notochord is a rod of cells filled with fluids. Function is to provide support. Gives rise to the shape of amphioxus.

Spinal cord is dorsal (along back of anima) and it’s hollow. Hollow part is filled with fluids that have oxygen and nutrients in it, so spinal cord can be better develop and coordinate muscle contractions better too

Pharyngeal slits- allow water to go through mouth and leaves through the pharyngeal slits. Is unidirectional which makes it perfect for catching microorgs / filter feeding. NOT USED FOR BREATHING gas exchange happens across its skin

Post- anal tail: located after the anus; primarily used for locomotion. Uses tail to burry itself in the sand. Hides in sand when predators is there and stands up when filter feeding.

Question 3

what chordate features do humans have?

Answer 3

he only chordate feature that humans have as adult is dorsal hollow spinal chord. Most other features found during embryonic development

Embryonic development can go wrong and be grown with these. Like post anal tail. Babies born with slits

Embryos of many organisms very similair which is evidence of a common ancestor

Question 4

what is the outgoup of vetebrates and why?

Answer 4

What is the outgroup? Why?

Amphioxus: most distant common ancestor. Doesn’t have a lot of feautures of the other animals. Has no backbone

Question 5

List the major advancements in the evolution of vertebrates and know the animals that possess them.

Answer 5

1. Vertebrae = backbones, replaces notochord. Vertebrae for support on land
   2. Jaws: hagfish and lamprey don’t have jaws. Hagfish only eat on dead matter and rip matter off. Lamprey likes blood. Vampire. Like leech
   Jaws allows for consumption of larger prey
   3. Lungs: stagnant water doesn’t have as much oxy. Water was uddy and the water temp was high. Fish evolved gills around pharyngeal slits. We think what happened was that the esophagus from outpocketings (2) and those 2 out-pocketings evolved into the lungs. nCan go to Surface and gulp air and use lungs to get oxygen.
      We think the two sacs becam seperated from esophagus and lung evolved into swim bladder.
   4. Limbs: fins got caught in shallow water which lead to the evolution of limbs.
   5. Amniotic sac: thing around embryo. Only saurpsods and mammals have amnitoic sac. Its a water filled bag. It helps to prevent dehydration. Like provate pod that allows for development on land. Also prevents shock waves from affecting baby. Water temp doesn’t change as much due to heat capacity. Keep temp constant so development can happen more efficiently. Yolk sac provodes nutrients in reptiles and bird. Placenta in humans. Baby puts waste and O2 into it, get nutrients and oxygen.
      DON’T SAY AMNIOTIC SAC PROVIDES NUTRIENTS
   6. In mammals; hair: provides insulation. In humans it makes up sensitive to touch. Dense hair like polar bear or seal provides insulation by trapping warm air.

Question 6

why and how did the lungs and swim bladder evolved?

Answer 6

stagnant water doesn’t have as much oxy. Water was uddy and the water temp was high. Fish evolved gills around pharyngeal slits. We think what happened was that the esophagus from outpocketings (2) and those 2 out-pocketings evolved into the lungs. nCan go to Surface and gulp air and use lungs to get oxygen.
We think the two sacs becam seperated from esophagus and lung evolved into swim bladder.

Question 7

why was the amniotic sac crucial for the development of vertebrates on land?

Answer 7

Its a water filled bag. It helps to prevent dehydration. Like provate pod that allows for development on land. Also prevents shock waves from affecting baby. Water temp doesn’t change as much due to heat capacity. Keep temp constant so development can happen more efficiently. Yolk sac provodes nutrients in reptiles and bird. Placenta in humans. Baby puts waste and O2 into it, get nutrients and oxygen.

Question 8

lamprey and hagfish

Answer 8

Both eel shaped animals. Hagfish eats decomposign matter, don’t need jaws because decomposing matter is soft

Laprey is vampire. Long covered in teet

Question 9

what do lamprey and hagfish feed on?

Answer 9

lamprey chomp onto fish and drink their blood. like vampires

hagfish feed on decomposing matter at the ocean floor

Question 10

have no paired fins. Swimming ability?

Answer 10

Don’t have paired fins because. Hagfish chills at the bottom of the ocean until dead carcus comes by. Swims short distance and then starts feeding.

Lamprey take rides from other fish and take blood too. Lamprey only swims when fish is latched on to is starting to die. Both don’t need to be good swimmers

Question 11

Why don’t lamprey and hagfish have vertebrae

Answer 11

No backbones because flexible. Allows the to escape from predators better and move side to side better. Also super slimey to get away from predators

Lost is because get away more effectively from predators.\

Question 12

what are chonrichythes

Answer 12

sharks

Question 13

what is the advantage of a cartilage skeletons

Answer 13

makes it faster and more flxible. Cartilage is very light to faster.

Question 14

sharks have paired fins that are rigid why.

Answer 14

can’t swim very quickly side to side but can swim up and down (like airplane) incredibly well. Pectoral fin is bigger because moves pectoral fin away from body to go up. Moving perctoral fin towards body makes it go down. Can’t manouver as well

Question 15

sharks have jaws that are not fused to the skull. Why?

Answer 15

Skull is fused to backbones, so shaped like a torpedo. Jaws not connected to skull, only by connective tissue. Can move jaws forward and back. Can suck prey in by suction.

Can clamp up and down

Question 16

shark teeth are embedded in the skin and point backward. Why?

Answer 16

Every time lose teeth another row replaces it and are sharper than the original ones. Super sharp teeth
Prey can’t go backwards out of mouth without hurting themselves

Question 17

what is the function of claspers in shark

Answer 17

shark penis. Peliv fins has projection called the clasper. (SHARK PENIS) cloaca = shark vagina Has groove along length and that groove allows for sperm tranfer, like penis.

 shark sex - Small ones criss cross

Big ones go belly to belly.

Question 18

what are osteocytes

Answer 18

fish

Question 19

fish have bony skeletons. What are the advantages and disadvantages?

Answer 19

Advantage: much stronger and denser than cartilage. Very low water content. Made of calcium and phosphate. They are the two minerals that make up bone, much stronger much more protected.

Disadvantage is that it's heavier so not as fast..

Question 20

swim bladder. Functions? How do sharks manage without a swim bladder?

Answer 20

Sharks don’t have swim bladder because it’s pushing water down with pectoral fins. More forward thiers fins are, the higher it goes. Like wings of the plane if stops swimming it sinks. Sharks don’t sleep. Go into half sleep state during day. Become more awake at night.

Question 21

operculum. Functions? How do sharks manage without operculums?

Answer 21

Operculum is a a structure covering the gills. Moves water past the gills. Improves water circulation thefore gas echange so can stop swimming and still breathe. Sharks don’t have operculum, so they are dependant on movement to survive

Question 22

fish have hug gonads. Why?

Answer 22

emale gonads have eggs so are bubbly structure male is flat. On lab exam just say gonads. Need way more eggs and sperm to fertilize more eggs outside the body. When not reproducing, the gonads are smaller so can swim better.

Question 23

describe amphibians

Answer 23

Most amphibians: not compltelty terrestrial, not completely aquatic. Still rely on water.

Question 24

frogs carry out external fertilzation. Why are eggs laid in the water?

Answer 24

The gel is not great. If exposed to air, dries up and dies. So need water. Don’t have egg or amniotic sac.
Thye eggs need to be fertilized in the water and once they develop must live in the water until, its developed enough to go on land

Question 25

metamorphosis from larva to adult. Why? How? in frogs

Answer 25

Dramatic change in structure in juvenile form. Kind limbs help to hop and get away from predator. Locomotion changes from aquatic to terrestrial. The wau they breathe changes. Their digestive tract changes. Their eyes change.

 The coiled intestines in tadpole are so that they can break down cellulose / vegetation. In intestines have. Have bacteria in digestive tract that breaks down glucose. Digestive tract is extremly short in adults because insects easier to break down

The eyes in tadpoles gives them 360 degree vision. Get depth perception in adults. (binocular vision) perfect for feeing on insects because can see how far it is. Go from 260 degree vision to 3D vision. Eyes shift forwards. Monocular to binocular vision. Body of animal become shorter, so have more stability for jumping.

Question 26

why do frogs carry put gas exchange across their moist skin?

Answer 26

Have gills first. Eventually get lungs that replace gills. Lungs poorly developed so gas exchange across their skin.

Question 27

frogs are ectotherms. What are the advantages and disadvantages?

Answer 27

body temperature is the same as outside enviro. We have dif body temp than enviro. Less energy use, don’t have toexpend energy keeping body temp different from surroundings. Don’ have to eat as much as we do. We trasmit heat to water in pools so get cold. They are aquatic, so helps maintain their body temp. all aquatic animals are ectotherms. Less active during winter. Amphibians are going extinct because of raising temp of water. There’s a fungal infection that uses their skin for breathing, so kills them.

Question 28

what are some examples of amphibians?

Answer 28

cave salamander, poisonous arrow frog, burrowing caecilian

Question 29

Sauropsids. What are they

Answer 29

scaly faced reptiles and bird

Question 30

carry out internal fertilization. Benefits?

Answer 30

cloaco of male and female “kiss” turns inisde out and inserts sperm into cloaca. Cloacal kissing ? Protectind sperm so they don’t dehydrate during transfer. Fertilization happens early in oviduct.

Question 31

saurposids have amniotic eggs. Benefits?

Answer 31

No longer need to rely on water. Regulates temperature. Absorbs shock. Yolk sac gives offspring nutrients and protects from outside enviro

Question 32

sauropsids ahve scales made of keratin. Function?

Answer 32

Prevents water loss. / dehydration. Prevents mechanical inury, less chance of scrapes.

Question 33

an be ectotherms or endotherms. Explain. Advantage? Disadvantages?

Answer 33

Ectotherms use sun as a source of heat. Less energy intake needed. Rely on the heat to keep them active. Can be so sluggish that they look dead.

Birds are endotherms. Have an inside source of heat that is their metabolism. Cellular respiration produces ATP and heat. Birds have higher metabolism of any other ogranism on the planet. Flight takes a lot of energy. Upside is that they can live anywhere. Will never be sluggish, but use way more energy so need way more food.

Question 34

Birds have a reduced body weight for flight. Explain.

Answer 34

have honey-combed bones. -keratin beak instead of bony jaws. More lightweight. Feathers overlap and trap warm air. This reduces heat loss. Feathers are waxy, so keep water out. Keeps birds insulated. Penguins are like wearing a dry suit. Keeps warmer than wetsuit. Penguins don’t touch water.

Hollow bones have ridges to strengthen the bon. Birds have no bone marrow. Have nuclei in red blood cells, so the cells last longer.

Their bones are fused, reduces number of bones and reduces number of muscles needed. Even ribs are fused together.

They have only one ovary and one oviduct. Don’t have bladders. Their poop is like toothpaste. Don’t store waste. Waste material called uric acid. Birds can’t shew, only tear or rip

Question 35

what are some examples of sauropsids?

Answer 35

Basilisk lizard, Mankin bird and crows

Question 36

describe mammals

Answer 36

produce milk for their young. - have mammary glands. Need milk to feed offspring

Question 37

mammals are endotherms – need hair to provide insulation. How? Why?

Answer 37

Birds are also endotherms. Maintain constant body temperature that is not dependant on environment. Powerhouses keep body temperature contant. Can live in pretty much any environment. (lions and bears). The downside is that you use up so much energy, more so than an ectotherm Hair traps warm air above the skin. Provides insulation and prevents you from being cold. Prevents heat loss. Our hair doesn’t have benefit of keeping us warm. We don’t have hair because we developed in africa, super warm, also evolved to have sweat glands. Natural selection played big role in us losing hair. Water evaporates and take heat with it when sweating.

What little hair we have increases sensitivity.

Question 38

mammals have heterodonts. Explain.

Answer 38

Different teeth. (size and shape) cananine “flesh”; molar “grind”. Birds have one way passage of air and use air sac. Mammals have diaphram to move air through lungs. Diaphagm is a exclusisvley mammalian trait.

Question 39

what are the different types pf mammals

Answer 39

monotremes are platypuses

marsupials: include kangaroos, koalas, wallabees

eutherians are like everything ells- humans, elephants

Question 40

describe monotremes

Answer 40

platypuses and primitive because one opening” for the passive of uring, feces and sex cells. Cloaca before opening. Primative because cloaca are only seen in reptile and birds. Includes platypus. They lay eggs and don’t have nipples, have milk patch instead, beneath are mammary glands. Milk oozes out onto hair. Only considered mammals because have hair and produce milk and have diaphragm.

amnitoic eggs are primitive because only seen in other animals

Question 41

describe marsupials

Answer 41

(kangaroos, koala, wallabees) have a skin pouch for the development of their premature young. Examples? Why is giving birth to premature young beneficial? When comes out baby is blind and hairless. Mom licks opening for that baby follows smell, then blindly searched for nipple. Force fed for frist month. Super premature because the placenta is poorly developed.

The advantage in premature young is that they live in such extreme environment. Contantly going from terrible rain to dry for months. They also have many babies, three young at different stages of development. They can stop producing milk, can abort pregnancy at any time when climate isn’t good.

Question 42

describe eutherians

Answer 42

true’ placenta. Why ‘advanced’?

Blood vessles of mom and fetus get really cose at placenta. Mom gets rid of extra carbon dioxide and waste.advantage is that fetus can develop compltley. Eyes, hair, sometimes can run away from predators.