chordates
Phylum Chordata
Characteristics displayed in (almost) all chordates at some point in their life cycle:
- dorsal hollow nerve cord
- notochord (dorsal rod of cartilage for support along body axis)
- Pharyngeal gill slits
- Muscular post anal tail
Lower Chordates
Subphyla:
- Hemichordata
- Urochordata
- Cephalochordata
- lack notochord (for this reason, some scientists believe this subphylum should be a separate phylum from the chordates)
- all marine
- primitive gill slits
- ex. Acorn Worm
- ex. Tunicates
- adult is a sessile filter feeder that bears no resemblance to a chordate
- adult has no notochord or dorsal nerve cord
- larvae is tiny and highly motile
- exhibits all chordate characteristics
- lasts for 1-2 days
- doesn’t reproduce
- uses this stage for species dispersal
- displays all four chordate characteristics in the adult stage
- often called “classical chordate” because of this
- segmentation
- believed to share a common ancestor with vertebrates
- ex. Amphioxus
Lower Chordates Lab
Analysis Questions
- The tunicate adult stage lacks a notochord and dorsal nerve cord but has the gill slits and post anal tail. The larvae displays all four characteristics. It is part of Phylum Chordata and Subphylum Urochordata. The Acorn Worm does not display a notochord at any point in its life. It does display primitive gills, a dorsal hollow nerve cord, and a post-anal tail (kind of). It is part of Phylum Chordata and Subphylum Hemichordata.The Amphioxus displays all four characteristics throughout its adult stage. It also displays segmentation. It is part of Phylum Chordata and Subphylum Cephalochordata
- Because it displays all four of the defining characteristics for chordates.
- The tunicate larvae is tiny, motile, and lives for a very short time. It also has a dorsal hollow nerve cord, a notochord, pharyngeal gill slits, and a post anal tail. The adult is sessile and reproduces. It does not have a notochord or nerve cord.
- Because the Acorn Worm has a dorsal nerve cord where all of the other invertebrate worms had a ventral nerve cord (if any nerve cord at all). Also, the Acorn Worm has gill slits and the invertebrate worms do not.
Higher chordates
Subphylum:
- Vertebrata
- Class Agnatha
- Class Chondrichthyes
- Class Osteichthyes
- Class Amphibia
- jawless fish
- more dominant in early oceans where they were mud suckers or filter feeders
- evolved gills to improve uptake of oxygen which increased activity levels
- no paired appendages
- ex. Lamprey, Hagfish
- cartilaginous fish (skeleton made of cartilage and not bone (secondarily evolved))
- jaws evolved by modification of anterior two pairs of gill slits
- no operculum (uncovered and unprotected gills)
- no air bladder (unable to control buoyancy)
- paired fins
- streamlined body
- well developed senses (especially smell)
- almost all predators
- internal fertilization
- carry eggs internally (young not nutritionally dependant on parent)
- ex. Sharks, Skates, Rays
- skeleton made of bone (which is made of calcium carbonate)
- dominant water vertebrate
- operculum (covers and protects gills)
- air bladder (formed as a pocket off of pharynx)
- Circulatory System
- have two chambered heart (1 atrium; 1 ventricle) that pumps blood to the gills then to the rest of the body
- Nervous System
- vertebrate brain
- well developed senses
- behaviour begins
- spinal cord
- Reproduction
- external fertilization and development
- little (if any) postnatal care
- young born able to swim and feed
- young independent from parents
- Excretory System
- dorsal kidney that excretes mainly ammonia and nitrogen wastes
- Types:
- Teleosts:
- true fish
- ray finned appendages
- most common fish today
- ex. Salmon, Perch, Trout
- Lung Fish and Lobe Finned Fish
- evolved in fresh water in a time when periodic and severe droughts occurred
- lung fish seen in Africa and South America
- lung fish use crude lungs to gulp air to assist gills
- lung fish usually live in stagnant waters
- Teleosts:
- Reproduction
- external fertilization and development
- larvae (tadpole) lives exclusively in water; has gills and fins
- undergo metamorphosis into land dwelling adult
- Respiratory System
- adults have sac-like lungs that come off of the pharynx
- 50% of oxygen intake from lungs; 50% of oxygen intake from skin
- Circulatory System
- 3 chambered heart (2 atria; 1 ventricle)
- blood mixes in ventricle and partly oxygenated blood goes to lungs
- Skeleton
- appendages come off of the side of the body
- ventral surface drags across the ground
- not well muscled tails and legs (for most)
- Nervous System
- brain size increased (cerebrum and cerebellum noticeably increased)
- land based ear (timpanum) and sense of smell
- Extra
- Cloaca: location where sperm/eggs, urine and feces are released
- Fat Bodies (frogs): store energy for hibernation; energy to create good eggs; helps frogs float (less dense than water)
- Repro
- amniotic egg
- internal fertilization
- not a lot of post-natal care (about 1 week)
- Resp.
- efficient lungs
- cover skin with scales, shells, or other leathery layers b/c skin is unneeded for respiration
- Circ.
- two atria
- partially separated ventricle (crocodilia has two ventricles)
- Nervous
- larger brain
- better senses
- cerebrum and cerebellum increased in size
- behaviours
- mate selection
- territoriality
- Skeleton
- appendages come off of ventral surface (no belly-dragging)
- Orders
- Rhynchocephalia
- ex. Tuatara (aka sphenodon)
- Chelonia
- ex. sea turtle, tortoise, terrapin
- Crocodilia
- ex. crocodiles, alligators
- Squamata
- ex. lizards, snakes
- Rhynchocephalia
- Archeopteryx
- earliest known bird
- part reptile (bony teeth, tail, claws) and part bird (feathers, lightweight hollowed out bones)
- Repro.
- both sexes only use left gonad
- cloaca
- “cloacal kiss” occurs quickly (sometimes 1 sec)
- sperm is stored by the female for 1-52 weeks
- amniotic egg - incubation, calcarious shell
- pre-natal nesting behaviour
- young born immature (post-natal care required)
- Nervous
- well developed senses (sight)
- brain develops greater cephalization
- behaviours
- mate selection
- territoriality
- Circ.
- endothermic
- homeostasis
- high energy cost = maximum oxidation of blood
- two atria, two ventricles
- spleen to remove old RBCs
- endothermic
- Resp.
- 7 or 9 air sacs in bones, wings, and cranium
- require two rounds of inspirations/expirations to complete a full cycle of air movement
- Flight
- high metabolic cost
- feathers (modified scales)
- structure
- follicle (sac in skin where feather grows from)
- rachis (central cylinder running length of feather)
- quill (part of rachis beneath skin)
- barb (flexible, branch off of rachis)
- barbule (link barbs together, branch off of barbs)
- vane (several barbs together)
- structure
- basic wing forms
- elliptical (quick manoeuvering)
- high speed (long migrations)
- soaring wings
- Extra
- head, trunk, tail
- lightweight hollowed out bones
- beaks, not teeth
- 2 wings, 2 legs
- uric acid excretion
- Circ.
- complete circulatory pattern
- 2 atria, 2 ventricles
- complete circulatory pattern
- Resp.
- highly efficient lungs with muscular diaphragm
- highly efficient lungs with muscular diaphragm
- Integumentary
- covered with hair for insulation and sensing (modified scales)
- endothermic
- layer of subcutaneous fat for insulation and food storage
- covered with hair for insulation and sensing (modified scales)
- Resp.
- internal fertilization and development
- amniotic egg: includes placenta
- mammary glands to nurse young
- young require extensive post-natal care
- internal fertilization and development
- Nervous
- most advanced in kingdom animalia
- great increase in cerebrum (convoluted)
- well developed senses
- behaviours
- learning and reasoning levels
- learning and reasoning levels
- brain
- frontal lobe: thinking, planning, central executive functions, motor execution
- parietal lobe: somatosensory perception, integration of visual and somatospatial information
- temporal lobe: language function and auditory perception, long term memory and emotion
- occipital lobe: visual perception and processing
- frontal lobe: thinking, planning, central executive functions, motor execution
- most advanced in kingdom animalia
- Skeletal
- limbs well adapted for land/water and allow for rapid movement
- limbs well adapted for land/water and allow for rapid movement
- Subclasses
- Prototheria - monotremes
- lay eggs, nurse young, have fur
- ex. duck billed platypus, anteater
- lay eggs, nurse young, have fur
- Metatheria - marsupials
- no uterus, pouch for development of young
- ex. opossum, possum, kangaroos, wallabies
- no uterus, pouch for development of young
- Eutheria - placental
- complete internal development due to placenta, dominant land vertebrate
- ex. humans, pandas
- complete internal development due to placenta, dominant land vertebrate
- Prototheria - monotremes
Class Osteichthyes lab
Class Amphibia lab
1. The nictitating membrane is a semi-transparent third eyelid that protects and moistens the frog’s eye while allowing them to see.
2. The position of its teeth suggests that it does not use them to chew, but to hold its prey in its mouth.
3. Tongue, mouth, pharynx, esophagus, stomach, small intestine, large intestine, cloaca.
4. O2 poor blood goes in right atruim, O2 rich blood goes in left atruim, both mix in the one ventricle, ventricle pumps the partly oxygenated blood into the main artery which transports the blood to the arteries, the arteries transport blood throughout the body
5. Internal or external nares, glottis, bronchi, lungs. Air can also enter through the frog’s skin and be directly absorbed into their bloodstream.
6. In males, the sperm is made in the testes. It travels from the testes to the ureters and then it exits through the cloaca. In females, the eggs are made in the ovaries. They travel through the oviducts, into the uterus and out the cloaca. Frogs use external fertilization.
7. The kidneys filter the blood and pull out the wastes which are converted into urine. The urine travels down the ureters into the bladder where it is held until it is excreted through the cloaca.
8. The spinal cord which has nerves that branch off of it.
9. The frog would lose the ability to move its legs. The nervous system carries messages from the brain to the nerves which allow for movement. If the nerves in the frog’s legs were cut, then the messages for movement would not be able to reach the muscles, therefore the muscles would not move.
10. Fat bodies store energy for hibernation, they help frogs float, and they store energy to create good eggs (in females).
11. The frog’s powerful hind legs allow it to swim quickly in water and jump large distances on land. This is a useful adaptation because it allows the frog to escape predators and catch prey quickly.
12. This shows that the tadpole probably has a difficult time surviving to adulthood. There are a lot of predators in the water that a tadpole would be unable to defend itself against. Therefore, the frog lays a lot of eggs so that some of them may survive to adulthood.
2. The position of its teeth suggests that it does not use them to chew, but to hold its prey in its mouth.
3. Tongue, mouth, pharynx, esophagus, stomach, small intestine, large intestine, cloaca.
4. O2 poor blood goes in right atruim, O2 rich blood goes in left atruim, both mix in the one ventricle, ventricle pumps the partly oxygenated blood into the main artery which transports the blood to the arteries, the arteries transport blood throughout the body
5. Internal or external nares, glottis, bronchi, lungs. Air can also enter through the frog’s skin and be directly absorbed into their bloodstream.
6. In males, the sperm is made in the testes. It travels from the testes to the ureters and then it exits through the cloaca. In females, the eggs are made in the ovaries. They travel through the oviducts, into the uterus and out the cloaca. Frogs use external fertilization.
7. The kidneys filter the blood and pull out the wastes which are converted into urine. The urine travels down the ureters into the bladder where it is held until it is excreted through the cloaca.
8. The spinal cord which has nerves that branch off of it.
9. The frog would lose the ability to move its legs. The nervous system carries messages from the brain to the nerves which allow for movement. If the nerves in the frog’s legs were cut, then the messages for movement would not be able to reach the muscles, therefore the muscles would not move.
10. Fat bodies store energy for hibernation, they help frogs float, and they store energy to create good eggs (in females).
11. The frog’s powerful hind legs allow it to swim quickly in water and jump large distances on land. This is a useful adaptation because it allows the frog to escape predators and catch prey quickly.
12. This shows that the tadpole probably has a difficult time surviving to adulthood. There are a lot of predators in the water that a tadpole would be unable to defend itself against. Therefore, the frog lays a lot of eggs so that some of them may survive to adulthood.
Class Mammalia labs
Rat Dissection Analysis Questions
2. The sphincter is circular to control the movement of fluids, etc. through circular organs (ie. the area where the stomach drains into the small intestine, the end of the bladder, etc.). Sphincter muscles ensure that fluids, etc. stay in the one organ (say, the stomach) until they are ready to exit (stomach -> small intestine once the chyme is finished being digested). They also prevent backflow.
3. The small intestine and large intestine do different jobs. The small intestine absorbs nutrients from food, which is liquid at this point, so it does not need to be large in diameter. The large intestine absorbs any water from the resulting waste. The waste goes solid, so the large intestine needs to be large in diameter.
4. It detoxifies the body and produces bile (stored in gall bladder) to digest fat.
5. The membranes hold capillaries that are used to deliver oxygen to cells and remove carbon dioxide. They produce a lubricating fluid that creates a protective surface for the organs and allows for things to move easily within the coelom.
6. The spleen removes old red blood cells and stores blood.
7. The diaphragm is the muscle beneath the lungs that allows the lungs to expand and contract for breathing.
8. The atria are located on top of the ventricles. They collect the blood that comes back from the body and the lungs while the ventricles pump blood that the atria collected to the lungs and the body.
9. The left ventricle has to pump blood to the entire body while the right ventricle only has to pump blood to the lungs, which is proximal to the heart. Thus, the wall of the left ventricle must be thicker to allow the strength to pump blood to the body.
10. Both are situated posterior to the kidneys. They both have organs for the production of haploid gametes used for reproduction and organs that transfer these gametes.
11. Kidneys filter the blood to remove metabolic wastes and toxins. The wastes are ammonia wastes and are transferred from the kidneys to the ureters. Kidneys aid in the production of urine.
3. The small intestine and large intestine do different jobs. The small intestine absorbs nutrients from food, which is liquid at this point, so it does not need to be large in diameter. The large intestine absorbs any water from the resulting waste. The waste goes solid, so the large intestine needs to be large in diameter.
4. It detoxifies the body and produces bile (stored in gall bladder) to digest fat.
5. The membranes hold capillaries that are used to deliver oxygen to cells and remove carbon dioxide. They produce a lubricating fluid that creates a protective surface for the organs and allows for things to move easily within the coelom.
6. The spleen removes old red blood cells and stores blood.
7. The diaphragm is the muscle beneath the lungs that allows the lungs to expand and contract for breathing.
8. The atria are located on top of the ventricles. They collect the blood that comes back from the body and the lungs while the ventricles pump blood that the atria collected to the lungs and the body.
9. The left ventricle has to pump blood to the entire body while the right ventricle only has to pump blood to the lungs, which is proximal to the heart. Thus, the wall of the left ventricle must be thicker to allow the strength to pump blood to the body.
10. Both are situated posterior to the kidneys. They both have organs for the production of haploid gametes used for reproduction and organs that transfer these gametes.
11. Kidneys filter the blood to remove metabolic wastes and toxins. The wastes are ammonia wastes and are transferred from the kidneys to the ureters. Kidneys aid in the production of urine.
Drawings of a Chicken at Various Stages of Embryonic Development