Lab 10

Question 1

Deutorostomes

Answer 1

echinoderms and chordates are deutrostomes
- the blastapore develops in the anus

Question 2

Phylum Chordata

Answer 2

having a chord

• about 50,000 species of chordates
• they live in the sea, freshwaters, land, and in the air

Question 3

Chordate Characteristics

Answer 3

there are vertebratata animals in the clade chordata (fishes, reptiles, amphibians)

• there are also invertebrate chordatas

**they all have bilateral symmetry, are triploblastic, and have a coelom

Question 4

Chordate Characteristsics - 1

Answer 4

1. notochord – it’s a flexible rod that supports the bodies of the chordata embryos and is still there in the adult cephalochordates and in the vertebrate chrodates

• it becomes part of the discs between the vertebrae in our backbone

in humans – reduced to intervertebral disks

*it also helps with development – it’s in the center of the embryo
- during development, it secretes factors that signal surrounding tissues that tell them which fates they will have

Question 5

Chordates Characteristics - 2

Answer 5

2. they have a dorsal, hallow nerve cord

*formed from the ectoderm that rolls into a hallow tube – develops into the central nervous system

• during the embryonic development, the central nervous system is first a band
• the band of nervous tissue folds into a tube which then becomes the spinal cord
• the dorsal nerve cord is near the dorsal notochord
• the nerve cord stays in adult cephalochordates and vertebrates, but urochordates don’t have the nerve cord when they develop

Question 6

Chordate Characteristics - 3

Answer 6

3. they have a pharyngeal slits
   - they are openings that connect the pharynx or throat to the outside of the neck

• the slits can develop into gills for some chordates
• the slits are there in adult cephalochordates and urochordates
• they work during filter feeding
• in some vertebrates, the pharyngeal slits are modified for gas exchange

humans – theirs is developed into the jaw and inner ear bones

Question 7

Chordate Characteristics - 4

Answer 7

4. they have tail that ends beyond the anus = postanal tail

• it’s a skeletal extension of the posterior end of the body that goes past the anus

*some chordates use it for locomotion

Question 8

2 Subphylum of Chordates - Urochordata

Answer 8

Subphylum Urochordata - they are usually called tunicates

• they have an outer covering (tunic) that protects them from predators
• some live as their own person and other form colonies
• most common type of tunicate are sea squirts

Question 9

Tadpoles

Answer 9

tadpoles are swimming larvae
- they have all 4 chrodate characteristics

• when they are sessile adults, they lose the notochord and tail
• their dorsal nerve cord gets reduced but they still have pharyngeal slits

Question 10

Adult Turnicate Body

Answer 10

they are suspension feeders - they are a sack with 2 siphons where water enters and exits

• the water is draw in and food gets trapped inside the sack-shaped body

*these are seq squirts because they squirt out water when they get distrubed

Question 11

Flow of water in Tunicates

Answer 11

the water flows into the mouth
- food gets trapped

• water is drawn into the pharynx and then passes thru the pharyngeal slits and then back out
• food is trapped in the pharynx and is passed to the rest of the digestive system
• undigested material leaves with the water, exiting the tunicate

Question 12

Characteristics of Tunicates

Answer 12

their notochord, dorsal nerve cord and tail are only present in the larval stage

• the adults are usually soft-bodied sac-like, sessile filter feeders

Question 13

2 Subphylum of Chordates - Cephalochordata

Answer 13

Subphylum Cephalochordata

• small fish-like animals called lancelets make up this subphylum

*they have all the chordate features as adults too

Question 14

Characteristics of Cephalochordates

Answer 14

they elongate, and are laterally flattened, fish-like animals

• the chordate special characteristics are still with them in adulthood
• they burrow in marine sediments

Question 15

Subphylum Vertebrata

Answer 15

all members of this subphylum have a head and a rigid structure around the brain called a cranium

• Hagfish have a cranium but don’t have vertebral column
• they are located in the subphylum vertebrata because they share a common ancestor that had vertebrae with all other vertebrates, but lose the vertebrae in their lineage

Question 16

Subphylum Vertebrata - Characteristics

Answer 16

The brain is enclosed in cartilaginous or bony cranium

• fewer pharyngeal gils slits (used for respiration instead of feeding) or modified into other structures
• notochord supplemented by or replaced with segmented vertebrae in most
• larger, more complex brains and sense organs
• more complex visceral organs
• includes fishes, amphibians, reptiles, birds and mammals

Question 17

Mammals diverged into 3 types

Answer 17

Monotremes - they lay eggs
- the young hatch and are sheltered in pouch where they feed on milk is secreted onto skin

Marsupials - that give birth to young that appear to be in an underdeveloped state
- the young crawl to a pouch where most of the developed takes place and the young feed

Eutherian - the mammals are diverse and the largest group of mammals
- they have a placenta and give birth to young that have finished embryonic developmental in the uterus and were nourished by the placenta

Question 18

Regulation of Body Temperature

Answer 18

they need to maintain their body temp within ranges to stay alive

endothermic chordates = birds and mammals

ectothermic chordates = fishes, lizards, snakes, amphibians

*body temp of endotherm stays within a narrow range even if the environmental temp changes

*ectotherm body temp mirrors the temperature in their surroundings

Question 19

Endotherms and Ectoderms in Heat

Answer 19

endotherms generate body heat internally
- ectoderms get heat mostly from the surrounding environment

***endotherms need more energy because they are making energy

• the transfer of energy is not 100% effecient
• most of energy is given off as heat
• endotherms needs to consume food to produce heat

Nutrient + Oxygen –> ATP (energy) + CO2 + H2O + Heat

Question 20

Energy Process

Answer 20

endotherms need more food and a bigger supply of food than ectotherms because they generate their body heat from these processes

• since O2 is needed, they need an effecient gas exchnage strategy
• heat is exchanged with the environment on the surface of the body of birds and mammals

*ectotherms can regulate their body temp by moving to a cold or warm place
- they are good at using behavioral strategies for temp regulation

Question 21

Types of Circulatory System: 2 Chmabered Heart, One Atrium, One Ventricle

Answer 21

Gills: Fish
- they have 2 chambered heart, one atrium, and one ventricle

deoxygenated blood from the body goes to the atrium then the ventricle of the heart

• the ventricle pumps the deoxygentaed blood to the gills and then the oxygenated blood is pumped to the body
• the body picks up CO2
• deoxygentaed blood goes back to the heart

*closed circulatory system

Question 22

Circulatory System: 3 chambered heart, 2 atria, 1 ventricle

Answer 22

Lungs: Amphibians and Reptiles
- 3 chambered heart, 2 atria, and 1 ventricle

• deoxygenated blood from the body goes to the right atrium and then to ventricle
• then to the lungs
• oxygenated blood goes from the lungs to left atrium and then ventricle which pmps it to the body (cycle then repeates)

***the single ventricle has deoxygenated and oxygenated blood in it
- the mixing of blood means the body will recieve less oxygenated blood from the ventricle than what the ventricle recieved from the lungs

Question 23

Circulatory System: 4 chambered heart, 2 atria, 2 ventricles

Answer 23

Lungs: Birds and Mammals, and Crocodiles
- 4 chambered heart, 2 atria, 2 ventricles

• deoxygenated blood from body goes to the right atrium and then to the right ventricle
• then goes to the lungs
• oxygenated blood goes from lungs to left atrium and then to left ventricles which pumps it to the body (cycle repeats)

*because there’s 2 ventricles, the deoxygenated and oxygenated blood don’t mix
- the left ventricle is pumping blood that is more oxygenated than the 3 chambered heart — this allows for a higher metabolic rate

Question 24

Tetrapods

Answer 24

fish are tetrapods closest relatives
- this tells us 4 legged-animals came from fish

tetrapod = vertebrate animal with 4 legs

Question 25

Tiktaalik

Answer 25

it's the fish that they found in the rock - it's a mix of characteristics - combo of fish and tetrapod features - it has flat head with eyes on top (tetrapod) - fins and scales on back (fish) - this animal had a neck - hip bones - the hind fins were evolving into legs *our arms and legs are derived from the hind fins of our ancestors (tiktaalik)

Question 26

Transition from Fish to Human

Answer 26

the transition didn't happen in 1 step, but happened gradually over time - tiktaalik is one of the earliest fossils that show us transition from water to land

Question 27

agnathans

Answer 27

organisms without jaws ex: hagfish - they also don't have paired fins

Question 28

Vertebrate chordates vs. invertebrate chordates

Answer 28

vertebrate chrodates: they have a bony or cartilaginous braincase (cranium) - they also have a vertebral column made of vertebrae which is a series of separate bones joined together as a backbone

Question 29

Lancelets

Answer 29

they are cephalochordates that live in the sea and burrow into the sand - only their anterior end which has tentacles is exposed - the notochord gives them internal support which allows efficient swimming

Question 30

Hagfish

Answer 30

they are like scavengers tounge = has tooth-like rasps that tear apart dead organisms sensory tentacles = around their mouth to detect food - they tie themselves into a knot which they use to bite off carcass pieces (adaption since they don't have a jaw) -- it also allows them to slip out of their own slime skeleton - made of cartilage - unique because they have a cranium but lost the vertbrae in evolution - still have notochord

Question 31

Hagfish pores

Answer 31

they have pores that secrete a protein when the animal is distrubed - the protein can turn serveral gallons of water into thick slime - the slime helps them get away from predators and it can suffocate the predator

Question 32

Lamprey

Answer 32

lampreys don't have appendages and their skeleton is made of cartilage - they only have fins along the midline (no paired fins) *hagfish and lampreys do gas exchange by gills - they have a cranium and partial vertebrae along the side of their notochord - many of them are parasitic -- they attach to prey and rasp thr the flesh and suck out the body fluids

Question 33

Cartilaginous fish

Answer 33

ex: sharks fins: they move the shark forward, stabalize them, and prevent them from rolling as they swim thru water -- the fins lift as they swim the shark skin is covered by scales which are like teeth - the scales are adpated to decrease drag and turbulence which helps the shark swim faster and quieter

Question 34

Skate

Answer 34

skates are bottom dwellers - their gills are on the ventral surface - water enters thru the spiracles on the dorsal surface so they can lie still on the bottom waiting to ambush prey or hide from predators - they have good camoflauge

Question 35

Diffs between stingray and skates

Answer 35

stingrays: - they have stinging barb - each of their pelvic fins is one lobe - they're viviparous (they give live birth to their young - like humans) skates: - have enlarged thorn-like scales along the midline of back or tail for defense - fins are divided into 2 lobes - they lay eggs

Question 36

Chondrichthyes - Cont.

Answer 36

sharks, skates, stingrays, sawfish, ratfish - they all have vertebrae and cranium - all have a skeleton made of cartilage - jaw is development which allows them to grasp and tear food - the jaws allowed early gnathostomes to use food resources that were unavailable to jawless fish - they have 2 sets of paired fins - pectoral and pelvic fins allow the fishes to have stability and move well - the other fins help propel them thru water

Question 37

Osteichthyes - Bony Fish

Answer 37

they have an endoskeleton made of bone 2 lineages of osteichthyes: - ray-finned fish - lobe-finned fish

Question 38

Ray-Finned Fish - Osteichthyes

Answer 38

ray-finned fish have fins that are webs of skin supported by many thin bones that look like a fan - the bones = rays ***the fin rays attach to the main skeleton by many bones at the base - the muscles control the movement pf the fins are located in the body *has paired fins - most do gas exchange by drawing water over the gills *have swim bladder

Question 39

Lobe-Finned Fish - Osteichthyes

Answer 39

the fines are muscular (fleshy) - the fin attaches to the body by one bone = humerus - muscles that control the movement of the fins are located in the fin

Question 40

Evolution of Lungs and Swim Bladder - Ray-Finned fish

Answer 40

the ray-finned fish has lungs: - they evolved as outpockets of the pharynx - the lungs evolved to new structure = swim bladder swim bladder: - gives fish neutral buoyancy which is the ability of the fish to use little or no energy to stay at specific levels of water - the fish can be in diff depths of water by changing the amount of gas in the swim bladder ***if you increase the gas, the fish rises ***if you decrease the gas, the fish sinks

Question 41

Lobe-Finned Fish - Osteichthyes

Answer 41

lobe finned fish have fleshy pectoral and pelvic fins with well developed bones and muscles - they have humerus - the muscles that control movement are located within the fin - the movement of their fins at the joint shows a high degree of mobility (more mobility than in the ray-finned fish) *they can rotate 180 degrees

Question 42

Tetrapods limb humology

Answer 42

tetrapod = animal with 4 limbs - they have 1 bone attached to the body - then 2 bones - then a lot of little bones - then digits = many long, thin bones that are arranged in a series (ex: fingers)

Question 43

Amphibians

Answer 43

they're tetrapods ex: frogs *amphibians are not fully terrestrial - they need moist conditions because of gas exchange with their skin *must go back to water to lay eggs and for the young to develop

Question 44

To be fully terrestrial

Answer 44

to be fully terrestrial, they must have: - limbs that can support the body on land - lungs instead of gills - reproduction that protects the fertilized eggs and embryos from drying out - skin that is not prone to drying out

Question 45

Amphibian Gas Exchange

Answer 45

the gas exchange surfaces in amphibians = skin and lungs skin - must be moist for gas exchange to happen lungs - divided into air chambers where gas exchange happens - amphibian air chambers are much bigger and fewer per volume than the air chambers of mammals - there is less gas exchange surface area per volume in amphibians compared to mammals *they don't have ribs or diaphragm

Question 46

Scales, Feathers, Hair

Answer 46

placodes - scales, feathers, and hair all develop from a tissue in skin = placodes placode is a homologous structure for snakes, lizards, birds, crocodiles, and mammals the bird changed the scales into feathers - the mammals changes the scales into hair

Question 47

Amniotes

Answer 47

amniotes: snakes, lizards, crocodiles, birds, and mammals - they have a terrestrial egg that is protected by amniotic membranes - their embryos have their own aquatic environment which means they don't need to be in water for development -- so the amniotes can live in drier environments - most mammals don't lay eggs -- the amniotic membranes are still present

Question 48

Snakes and Lizards - Terrestrial

Answer 48

snakes and lizards = fully terrestrial - they have ribs - their muscles contract between the ribs which moves the rib cage so the lungs can ventilate - they don't have a diaphragm - they have better developed lungs than frogs -- more air sacs which means greater gas exchange surface area to volume *have 3 chambered heart *their skin prevents dessication - they don't need to live in moist environments *can't do gas exchange across their skin *scales of snakes and lizards are formed from ectoderm and fish scales are from mesoderm (not homologous !!!)

Question 49

Feathers

Answer 49

feathers = lightweight but strong - feathers and scales of snakes etc are homologous structures - they develop from the same tissue - hair of mammals develops from the same tissue - also homologous ***birds have high metabolic rate which generates heat - feathers help to make use of the heat by providing insulation

Question 50

Gas Exchange for Birds

Answer 50

air flows in one direction thru the respiratory system - inhaled air enters the posterior sacs which then pump new air into the lungs where O2 moves from air to blood - CO2 moves from blood to air - the stale air (air that just gave the O2 to the blood) leaves the lungs and enters the anterior air sacs which pump the stale air out of the body ***this one directional flow of air and the air sacs doing the pumping means that each time the bird inhales, fresh air enters the lungs which allows more O2 to get into the blood - then the cells can support the high metabolic needs

Question 51

Birds, Mammals and Crocodile Circulation

Answer 51

deoxygenated blood is recieved by the right atrium and then pumped to the lungs by the right ventricle - the oxygenated blood is recieved by the left atrium and then pumped to the body by the left ventricle