Vertebrates Flashcards
Chordates + characteristic
- group of animals that include fish
1) dorsal hollow nerve cord
2) notochord
3) muscular post-and tail
Explain pharyngeal slits, gills filaments, gill arches
Pharyngeal slits are located on lateral surface of head, function is for filter feeding, respiration in vertebrates, the water comes in mouth and passes through the slits, 02 and C02 can also be exchanged across the gills, the bars between the slits are gill arches that is bone or cartilage, gill filaments on the gill arches.
How many pairs of gill arches do bony fish have?
- 4 pairs of gill arches, each has a pair of gill filaments
- also have a gill cover (operculum)
Gill filament structure:
- thin, vascularized, high surface area
- blood vessels flow through arches
- gas exchange
- water and blood flow in opposite direction
What is concurrent change?
When blood and water flow in opposite directions. It ensures that partial pressure gradients are maintained and achieves the max amount of gas exchange.
Fish circulatory system
- closed system
- arteries (away from heart) -> arterioles -> capillaries -> venules (to heart) -> veins
Fish heart <3
- 2 chambers (auricle/atrium and ventricle)
- strong, muscular pump
- maintain blood flow
- one-way valves inside
Gnathostomes vs agnathans
Agnathan has jaw, other does not
What are two types of skeleton that vertebrates can have?
Axial skeleton: - cranium (skull) - vertebral column (spine) -ribs Appendicular skeleton: - pectoral girdle - pelvic girdle
What are two groups of Gnathostomes?
1) Lampreys: very distinct larval form, are parasite on fishes
2) Hagfish: knot tying, used for leather products, produces mucous
How were jaws formed?
Formed by fusion of gill arches, teeth evolved from scales in mouth, they improved feeding and diversify
What is a PRO about paired fins?
- more active swimming, steering, stabilizing, life
- on pectoral and pelvic limb girdles
Characteristics about Gnathostomes
- shark, skates, rays
- mostly marine
- paired fins
- scales
- predators, scavengers, filter-feeders
- no swim bladder
What is swim bladder?
Flotation device
Enables neutral buoyancy (float)
Gas regulated by gland in bladder or by swallowing/burping air
What is swim bladder?
Flotation device
Enables neutral buoyancy (float)
Gas regulated by gland in bladder or by swallowing/burping air
What are two groups of bony fish?
1) Ray-finned fishes
2) Lobe-finned fishes
What are types of amphibians?
frogs, toads, newts ect.
Coelacanth
” a living fossil”
thought to be extinct but then found in south africa and in indonesia market
Why did amphibians move on land?
Devonian droughts that caused shallow inland seas, swamps, pond,
Low dissolved 02
Caused increase in competition in the water, crowding
New recourses on land and no predators yet
What are some key differences between life on land vs water for Amphibians?
- availability of water/moisture
- density of medium
- oxygen (more oxygen on land so it was better, also gases dissolved faster on land)
- temperature
- UV radiation
Lung Evolution (lobe-finned fishes)
- 2 ventral pockets formed off esophagus, used as supplemental respiratory device
What are some of the problems experienced when amphibians moved onto land?
1) water needed to survive (stay moist)
2) air less dense than water (stronger skeletal support and need more energy)
3) air temp. so body temp will fluctuate more
4) UV radiation more intense on land
Once amphibians switched too on land, they needed to improve their skeletal support. How did they do this?
Tetrapods!!!! Stronger limbs, vertebral column, ribs, more efficient circulatory system (3 chamber heart, double circuit blood flow)
Compare the Fish circulatory system vs the Amphibians?
Fish: 2 chambered heart, blood oxygenated in gills (in water) , single circuit circulation (less pressure)
Amphibians: 3 chambered heart, blood oxygenated in lungs and skin (on land), double circuit circulation (higher pressure)
BREATHING PROCESS (Amphibians)
Positive pressure breathing
Inhalation is a 2 stroke process
1) Air drawn into nostrils, mouth (glottis remain closed)
2) Nostril close, glottis opens and air is forced into lungs
What are the two life stages of amphibians?
1) Larvae
- herbivores, 2 chamber heart, gills
THEN METAMORPHOSIS
2) adult, 3 chambered heart, carnivores
What are some different types of amphibians?
- Salamanders (some never leave water, some internal fertilization)
- Frogs & toads (largest group, loud courtship calls to females)
- Caecilians (internal fertilization, lost appendages)
Reptile Characteristics
- Fully terrestrial
- more efficient heart
- only breathe via lungs
- skin is waterproof by “B- keratin”
- produces special nitrogenous waste (uric acid)
- reproduces and develops on land (internal fertilization and amniotic egg)
Reptile Heart
Turtles, snakes, lizards - have partially divided ventricle
Crocodilians - fully divided ventricle, into 4 chambers
Amniotic Egg
Egg surrounded by extra - embryonic membrane
The shell is leathery or brittle, permeable to gases, fairly impermeable to water, NOT in therian mammals
Parts of Amniotic Egg
- Water in albumen (mechanical support)
- Shell
- Embryo
- Yolk sac (nutrients)
- Alltantios (waste)
- Amnion (contains embryo)
- Chorion (allows gas exchange)
What do excretory organs control and what do they excrete?
- they control volume, concentration and composition of extracellular fluids and excretes waste
- They excrete: salts + ions (released by skin, gills, kidneys or specialized glands), water, fecal matter (digestive system), nitrogenous waste (by kidney and gills, product of protein & DNA metabolism) also (Ammonia, urea, uric acid)
Who excretes Ammonia and what is it?
- Ray-finned fish, aquatic inverts, larval amphibians
- very soluble in water
- toxic
- needs to be diluted & disposed quickly or changed to less toxic form (urea or uric acid)
Urea VS Uric acid
Urea - less toxic, most adults/mammals excrete this
Uric acid - insoluble in water, not toxic, reptiles/birds/insects
What are the 3 main types of non- avian reptiles? (not relating to birds)
1) Testudinia (turtles and tortoises)
2) Crocodilia (crocodiles/aligators)
3) Lepidosauria (lizards and snakes)
What is a squamate?
- type of lizard
- snake, lizard, worm
- very diverse
- evolutionary loss of lungs, can regrow
Archaeopteryx
“ancient wing”
- 12+ fossils, crow-sized
- bird characteristic, wings+ feathers
- non-bird, teeth + body tail
What is the difference between Homeotherm and Heterotherm?
Hemeotherm (constant temp)
Heterotherm (variable temp)
Ectotherms vs endotherms
Ectotherms: absorb external heat
Endotherms: generate their own internal heat through metabolic process
What are 3 mechanisms to maintain body temperature?
1) Behavioural: moving locations, orientation relative to heat source (huddling ect)
2) Physiological: too hot: sweating, increase blood flow
too cold: shiver, decrease blood flow
3) Physical: Insulation (fat/feathers), surface area, colour
Birds Respiration
- Demand high amount of oxygen
- much more complex + efficient system compared to mammals (unidirectional flow of air through lungs, numerous air sacs (8-9))
- Ventilation (it takes 2 cycles)
1. air drawn into posterior air sacs, propelled through lungs
2. same air drawn into anterior sac, propelled through nairs
Birds - evolution of flight
- evolved at least four times
- adaptions for flight: hallow bones, sternum enlarged and keeled (increase surface area), feathers (have B keratin from scales)
What are the 3 unique features of mammals?
1) hair
2) sweat glands
3) mammary glands (milk production)
Evolution of mammals
- early mammals were small, arboreal, shrew-like
- their jaw became their ear
- coexisted w/ dinosaurs
Ambulocetus
- Ancestor to whales
- ear similar to whales/can hear underwater
- similar teeth to cetaceans
What are two mammals that went extinct because they were hunted by humans?
Megatherium - elephant sized, giant sloth
Smilodon - saber - toothed cat
What are the 3 groups of mammals?
1) Prototherians (platypus)
- lay shelled eggs, mammar glands (no nipples),suck from fur, females lack placenta
2) Marsupials (kangaroos)
- don’t lay eggs
- short gestation, long nursing period
- complete development in pouc
3) Eutherians
- no pouch or shelled eggs
- amniotic egg in female productive tract
- nourished by mother placenta
- bears, hamster, dear
Placenta
- Site of gas, nutrient and waste exchange between mother and embryo
- produces hormones necessary to maintain pregnancy
- organ formed by embryo and mother after implantation
Circulation pattern in fetus
1) oxygenated blood from placenta enters right atrium by inferior vena cava
2) goes to left atrium
3) ductus arteriosus connects aorta w/ artery, blood away from lungs and into aorta
4) blood travels through head and body via placenta
Molecular movement across placenta
- small molecules move via diffusion
- 02 and C02
- fetal hemoglobin has higher oxygen than adult, so the oxygen moves to fetus
- urea, nutrients, hormones, alcohol + drugs
Primates
- grasping limbs w/ opposable thumbs
- forward facing eyes (depth perception)
- big cerebrum
- social
Two major groups of Primates
1) Prosimians
- mostly aboreal & nocturnal
- ex. lemurs
2) Anthropoids
- carnivorous
- humans, gorilla
what do new world monkeys have that old world monkeys don’t?
Prehensile tails, flat noses and tend to be aboreal (related to trees)
What did the 2009 fossil suggest for primates?
That they did not walk upright and used arms to walk, and had a primitive toe that could grasp onto tree like ape
Australopithecus
ALL EXTINCT
brains 35% size of human brain
evidence that walking evolved before brains
Development of humans - two types of homo sapiens
1) Homo Habilis “handy/skill-full”, shorter jaw, bigger brain
2) Homo erectus “standing”
- first use of fire
- large as modern humans, smaller brain, thick skull
Mammalian Nervous System
1) Central Nervous System - dorsal hollow tube of tissue, brain and spinal cord that is protected by done
2) Peripheral Nervous System - cranial nerves (brain), spinal nerves (spinal cord)
4 parts of the central nervous system
1) conscious - sight, smell, sound
2) unconscious - blood pressure, body temp.
3) voluntary - muscles movement
4) autonomic - heart rate, sweating
Cerebrum
- divided into 2 hemispheres
- top layer = cerebral cortex, rich in cell bodies
- left side communicated with right side, vice versa
Limbic System
- amyglada, hippocampus, nucleus accumbens
- basic physiological drives, hunger, thirst, emotions, memory
- pressure and pain centres
