Vertebrate Animal Flashcards
Pre-lecture video of fish-1
Lamprey
Anadromous
Ammocete
Natal
Coho salmon
Parr
Pink salmon’s behavior & difficulties (beaker dam, waterfall, predators including people)
-redds
-reproduction: f-vent, m-milt, f-put small rocks on the bigger rocks
Smolt: the small salmon that first go into the river
Threespine stickleback: f-lay the eggs, m-sperm, take care of the nest and the baby fish
Phylogeny of the “fish”
Not monophyletic
There is no evolutionary group of fish
Deuterostomes
Common ancestor evolved coelom
-Coelom: Fluid-filled interior for their body & contain all their organs
Their synapomorphy 共源性状 is pharyngeal gill slits (function: respiration and feeding, human have too)
Chordata
Dorsal hollow nerve cord: nerve cross though, innervate the body, let electric signal through out the body
notochord:
-Rigid structure partially integrated into the nerve cord
-precursor of spinal
-not bone, not segmented, but long fluid-filled vesicles
muscular, post anal tail:
Function: locomotion
Often lost in evolution
Pharyngeal slits (pouches)
-Located on lateral surface of head
-Ancestral trait in deuterostomes
-Lost in echinoderms
-In vertebrates, pharyngeal tissue supported by arches
Can find the corresponding arches in human jaw and other structure
Function:
Filter feeding
Respiration in vertebrates
-water passes through
-O2 & CO2(get from water) exchange across gills
Gill-position
Located between slits, supported by arches
Vertebrates characteristics
axial skeleton:
-cranium
-vertebral column
-ribs
appendicular skeleton:
-pectoral girdle
-pelvic girdle
closed circulatory system:
-ventral heart
organs suspended in coelom
- Gill slits and gill arches
Pharyngeal slits = gill slits (only vertebrate, function same)
Bar between the slits = gill arches
-made of bone or cartilage
-gill filaments are on the gill arches
2 parts of gill arches:
1.gill raker-filter feeding
2.gill filaments-O2 exchange
Bony fishes
4 pairs of gill arches
Each arch has pairs of gill filaments
Gill cover-operculum
Gill filament structure
Thin, vascularized, high surface area
-Blood vessels flow through gill arches
-Capillary in gill filaments-gas exchange
-Filament epithelium is one cell thick(1-2 μm)
-Water & blood flow in opposing directions——countercurrent exchange
Definition and advantages of countercurrent exchange
Blood flows in opposite direction to water flow
Ensures partial pressure gradient——achieves maximum exchange of gases (gases in blood always have the lower concentration)
- Fish circulatory system
Close system
Arteries(away from heart)->arterioles->capillaries->venules(to heart)->veins
Heart & veins-ventral
Arterial-dorsal
Fish heart
-2 chambers
-Strong muscular pump
-Maintain blood flow
-one-way valves inside
Agnathostomes (7 features)
Jawless fishes
2 groups: Lampreys and hagfish
Characteristics:
-no jaws
-cartilaginous skeleton
-notochord present
-gill slits
-no paired fins
-no swim bladder
-no scales
Lamprey (Petromyzontoidea)
No jaw (oral disc)
Very distinct larval——ammocete
Adults of many species are parasitic on fishes
Have big impact on the ecosystem
Hagfish
Scavengers
Osmotic concentration same as sea water
Used for leather products
Knot tying
Mucous production(slime)
Jaws
Not present in early fishes and present agnathans(无颌类)
Formed by fusion of gill arches
Teeth evolved from scales in mouth
Greatly improved ability to feed and diverisify
Paired fins
Enable more active swimming
Used for steering, stabilizing, and lift
Pectoral fins
-human arm come from
Pelvic fins
-help stabilizing
Gnathostomes part 1
Sharks(high diversity, smallest 16cm, largest 18m), skate, rays
Mostly marine
Jaw
Paired fins
5-7 gill slit pairs
Scales
No swim bladder
Predators, scavengers, filter-feeders
Skates and Rays: some are predators, some are filter feeder
Gnathostomes part 2
Bony fishes
Largest vertebrate group
Jaws
Opercula
Paired fins
Scales
Swim bladder
2 groups:
Ray-finned fishes (teleosts)
Lobe-finned fishes (lungfish, coelacanths)
Swim bladder
Flotation device
Enables neutral buoyancy
Gas regulated swallowing air or by gland in bladder
Evolved into tetrapod lungs
Swallowing air, go through stomach and go into the bladder
Gland in bladder (counter current exchange, change the chemistry in blood and release oxygen into the swim bladder)
Ray-finned fishes
Have cartilaginous rays in their fins, these fishes are called actinopterygians.
Teleosts
Deep sea anglerfish:
use bio luminescent lures, pheromones
males are parasitic, bite on to the female, and they never let go, their bloodstream fuses with that of the female
Lungfish
6 species
“Walk on lobe-fins”
Breath through gills & primitive lungs
Estivate in mud during droughts
Coelacanths
Only 2 species are found now.
South Africa & Indonesian fish market
Reasons to move on land
Selective pressure: Drought ~400 mya——water became shallow, with low dissolved oxygen
- More oxygen on land
- Increased competition in water
- New food resources on land
- No vertebrate predators on land
Difference between land and water
Advantages:
More oxygen
Disadvantages:
-Availability of water- less moisture on land
-Less density on land- cannot float
-Stability of temperature- more stable in water
-amount of UV radiation- more UV radiation on land
Advantages of terrestrial respiration
-Air: higher concentration of oxygen
-Gases diffuse faster in air
External gills
Internal gills
Lungs
Tracheae
Lung evolution
Lung from lobe-finned fishes, evolve to guts, and finally lung
Why do we choke?
The pathway for food and the pathway for air have overlap area. Food sometimes can block the air pathway
Problems on land
- water needed to prevent desiccation
• need to stay moist
• most require water for fertilization & larval development - air is less dense than water
• require stronger skeletal support, muscles
• require more energy, more O2 brought in & distributed - air temperature is more variable
• body temperature will fluctuate more
• need to modify behavior or physiology - UV radiation more intense on land
• need physical protection or change behavior
Solution of the density problem
Evolve stronger limbs, vertebral column, ribs——hold your body
Tiktaalik
Early tetrapods
-Stronger limbs and girdles, vertebral column, ribs
-Tail used for balance, not swimming
-Lungs were primary respiratory organ
-External & internal nostrils (nares)
Lchthyostega
Circulatory system in fish and amphibians
Solution of require more energy, more oxygen
Fish: 2-chambered heart, single circuit citrculation
Amphibians
Positive pressure breathing:
3 chambered heart
Double circuit of blood flow
Advantages: blood under higher pressure, repressurize
Disadvantages: blood is mixed
Breathing mechanisms
Positive pressure breathing-Amphibians
Inhalation is 2 step process
1.Air is drawn into nostrils while mouth & glottis remain closed. Outer higher, gas go in.
2. Nostrils close, glottis opens and air forced into lungs. Mouth higher, lung lower.
Negative pressure breathing-Human
Boyle’s Law-volume increase, pressure decrease
Air go from high pressure to low pressure
Gases enter: volume of cavity increases, air pressure decreases, outer higher
Gases exit: volume of cavity decreases, air pressure increases, inner higher
Amphibians
~6000 species
First tetrapods
Fresh water & terrestrial (dependent on water)
Smooth, moist skin (glands)
Carnivores
Teeth
Two life stages
Larve: similar as fish
Gills
2-chambered heart
herbivorous
most undergo metamorphosis
Adults:
Lungs
3-chambered heart
Carnivores
Amphibian diversity
1.Salamanders (Urodela)
– some have internal fertilization – some never leave water
2.Frogs and toads (Anura)
– has the most species
– typically have loud courtship calls to females
- Caecilians (worm like, can be highly toxic, most time in water or underground, baby eat mom’s skin for nutrition)
– have lost appendages (limbs)
– internal fertilization
Newts:
-some are highly toxic
-Some region: co-evolution with Garter snake (resistant to the toxin), newts are really toxic
-other places: newts not that toxic, snakes cannot resist these toxin
Parental investment Strategies
2 extreme strategies:
1.Produce billions of offspring, provide no care, hope some will survive
2.Produce 1 offspring, care for it until maturity
Most amphibians provide little parental care to their young
Reptiles in phylogeny
Reptiles, like fish, is not monophyletic.
Birds are not called reptiles, but actually they are in the same evolutionary group
Features of Reptiles
Misnomer-fully terrestrial, because some species are living in the water except laying eggs
More efficient heart
Special nitrogenous waste
Amniotic egg
Skin is waterproofed(beta-keratin)
Only breath with lung
More efficient heart and circulatory system
Fish: 2-chambers heart, single circuit
Amphibians: 3-chambers heart, 2 circuit allow re-pressurize blood
BUT single ventricle, mixing the deoxygenated and oxygenated blood
Reptiles: 3-chambers heart, 2 circuit(some have the 3rd circuit, to breath underwater, blood does not go to lung)
a septum between the 2 ventricles, partially divided heart
Crocodilians have fully divided ventricles: 4 -chambers heart
Birds and mammals: completely separate 2 circuit, 4-chambers heart
Human fetus also have shunts like reptiles
Amniotic egg
Egg surrounded by extra-embryonic membranes
-Leathery or brittle (CaCO3)
-Permeable to gases & water, to allow gas exchange, the egg cannot be submerged
-not present in therian mammals
Egg structure:
Outside: Albumen-provide support
Several membranes:
-Allantois: contains waste
-Amnion:contains embryo
-Yolk sac: provide nutrients
-Chorion: allow gas exchange
Consequences of a terrestrial egg
1.internal fertilization
shell & albumen are added to the fertilized egg in the female’s oviduct
2.non-toxic nitrogen waste product is required
uric acid
Excretory Products
-Salts and ions
-Water
-Fecal matter(form digestive system)
Nitrogenous wastes:
Product of protein & DNA metabolism
Released by excretory organs(kidneys), skin and gills
-Ammonia(NH3):
Soluble in water, but toxic-need to convert to less toxic form
Things live in water
-Urea:
Soluble in water, medium toxicity
Less water needed for disposal
cartilaginous fish, most adult amphibians, mammals
-Uris acid
Insoluble in water, not toxic, little water need for disposal
Insect, reptiles, birds
Perfect for amniotic egg
Vertebrate excretory organ
Kidney
Regulate levels of water and dissolved solutes in blood to form urine
blood go to glomerulus, forces out small molecule in to Bowman’s capsule, go down, capillaries suck the glucose and urea back
Diversity of Reptiles
Lepidosauria-lizards and snakes
Tuataras
Testudinia-turtles
Crocodilia- alligators, crocodiles
Non-avian Reptiles
~ 6,000 species
-mostly terrestrial
-carnivores, herbivores, omnivores
-dry skin, scales
-first amniotes
Testudinia
Turtles and Tortoises
The dorsal and ventral bony plates form a shell. Dorsal shell is an expansion of the ribs.
Most are aquatic, some terrestrial. Sea turtles
come ashore to lay eggs.
Crocodilia (aka Archosaurs)
Crocodilians: crocodiles, caimans, gharials, and alligators
-Spend much of their time in water (nest on land or floating piles of vegetation
-All are carnivorous
Lepidosauria
Squamates: lizards and snakes
All skin covered with horny scales
gas exchange only through the lung
Tuataras
Resemble lizards have several different characters; only two species survive, and now only one left
-nocturnal
-well-developed parietal eye: sensitive to light like another sense
Squamate: lizards
Highly diverse
Some lost leg (limbs)
Gecko
Komodo dragon can gets to 3 m long
Squamate: Amphisbaenia
limb girdles much reduced– no legs except in Bipes
• eyes are reduced, no ear opening
• scales fused into rings (annuli) encircling the body
Squamate: snakes
no limbs
200+
highly kinetic skull-dislocate jaw
vomeronasal organ (in other organisms too)
ancestor of birds
Shared features with dinosaur
• bipedal, 3 hind toes
• carnivorous
• 4-chambered heart
• similar lungs
• feathered
• hollow bones
• parental care of eggs and juveniles
Archaeopeteryx
Feathers & wings-bird characters
Teeth & bony tail-non-avian characters
Birds (Aves)
Diverse ~9600 species
amniotes
Endothermic
4-chambered heart(completely separate circuit)
Feathers
Most fly
Diverse beak shows diverse diet
Body temperature control——2 main groups
Ectotherms
Absorb heat from external environment
Endotherms
Generate our internal heat through metabolic processes
Less efficient at transforming energy (eg. convert food to ATP)
Endotherm vs. Ectotherm
Homeotherm vs. Heterotherm
Endotherms (generate own heat, but not always keep body temperature constant)
Heterotherms (body temperature fluctuate)
Homeotherms (keep body temperature constant)
Ectotherms (rely on external heat)
Thermoregulation Mechanisms
- behavioral
• orientation relative to heat source, basking, huddling & varying contact with heat surface
• moving locations throughout day
2.physiological
• too hot: increase blood flow to periphery, sweating, panting
• too cold: decrease blood flow to periphery, shiver
3.physical
• insulation (fur, feathers, fat)
• surface area: volume
• colour
- Behavioral Thermoreagulation
Lizard’s microhabitats
Morning: bask on the rock
Middle of the day: go down to burrows to cool down
Although it is ectothermic but body temperature remain relatively constant
Penguins huddle
- Physiological Thermoregulation
Example: human thermostat
negative feedback system in hypothalamus
– if temperature is too high: sweat – evaporative cooling
– if temperature is too low: shiver – generate metabolic heat
- Physical Thermoregulation
Example: amount of fur, fat, surface area
Jack rabbit and arctic hare
- Other thermoregulation techniques
Conter-current heat exchange
Brown adipose tissue
Birds’ respiration system
Flying and endothermy need high amount of oxygen
Unidirectional flow of air through lungs
8-9 air sacs
Ventilation in birds:
-Breath 1: air breathe in to the posterior air sacs, as breathe out, air go into lung
-Breath 2: when breath in, air go into the anterior air sacs from lungs, as breathe out, air goes out
Birds exchange 100% of air in their lungs every time
Evolution of flight
4 independent evolution of flight
Gliding is not fly, it’s due to convergent evolution
Adaptations for flight (3)
1.Hollow bones
2.Sternum enlarged and keeled-increase surface area for attachment of large flight muscles
3.Feathers
Feathers
Function: insulation, flight, sensory, lining nests
composed of beta-keratin, shows derived from scales, most birds have reptile-like skin on leg
Ground-up or trees down?
Ground-up
Using wing to take off the ground for the ground reaction force off their feet which increases speed
At first, wings is using to improve speed and leaping
Mammals’ 3 unique feature
1.hair
Insulation, camouflage, sensory and defense
Independent evolution of hair and feathers
2.sweat glands
- Mammary glands
Milk production
Synapsid
A traditional way to identify different groups
Mammals have a single hole in the skull, so that muscles can come through the jaw and then attach the skull
Mammal evolution
Middle ear bone is derived from the skull (jaw part), and the bone in the jaw is derived from gill arches
Ancient mammals
Mammals did not radiate until extinction of the “dinosaurs”, coexisted with “saurs”
Mammals who lived with “saurs” were not so wussy after all
Back to the Sea: multiple separate origins of extant marine mammals
Ambulocetus is the possible ancestor to whales or evolution cousin of whales. Ear(can hear under water) and teeth similar.
The age of mammals
Cenozoic (66MYA to now)
Megatherium: herbivorous
Smilodon: saber-toothed cat
Mammals’ other features
Endothermic
4 chambered heart
Advanced nervous system
Internal fertilization
Heterodonty-different teeth specialized for different tasks (unique feature for mammal)
Mammal groups (3)
1.Prototherians
Lay egg, incubate egg until hatching
2.Marsupials
Pouched
3.Eutherians
Embryo retained in female reproductive tract
Prototherians
Unique features:
1.Lay shell eggs
2.Have mammary glands (no nipples, young suck milk from fur)
Platypus-eastern Australia
use bill dig for prey (worms)
2-4 egg, hatch 8day, nurse 5 months
Only venomous mammal (spur on back leg)
Venomous: have toxin, inject to you; Poisonous: make you sick if eat it
Echidna
Fully terrestrial, lay external eggs, hatch 8 days, in pouch spines form ~3 weeks, live ~50 years
Sticky tongue
Marsupials
-Viviparous, nurse with placenta
-Short gestation(birth after short internal development), long nursing period
-Newborns crawl over mother’s body to pouch, attach to nipple in pouch, until complete development
Kangaroo
Tasmanian devil
Possum
Tasmanian Tiger
Marsupial evolution: convergent evolution with other mammal
Eutherians
94% of species
Viviparous
Embryo nourished by mother via placenta (amniotic egg remain in female’s reproductive tract)
Eutherians often referred to as placental animals but some marsupials have placentas
Placenta
Organ formed by the embryo & mother after implantation
-formed by extraembryonic membranes & uterus lining of mother
-site of gas(O2, CO2), nutrient, waste(urea), hormones, and also other things(alcohol & drug) exchange between mother and embryo (small molecules move via diffusion)
-2 separate blood system, no mixing of blood cells or plasma
-produces hormones necessary to maintain pregnancy
Primates
- Arboreal ancestor
- Grasping limbs with opposable thumb
- Forward-facing eyes: depth perception
- Big Cerebrum
- Highly social: reduced brood size and extended parental care
2 major groups of primats
Prosimians
Anthropoids
Prosimians
- Mostly arboreal & noctural
- now just Madagascar (lemurs) & Africa/SE Asia
Tarsiers
- phylogenetic position uncertain, might paraphyletic with prosimians
- Among the smallest primates
- The only entirely carnivorous primate
Anthropoids: New World vs. Old World
Prehensile tail: tail used to grasp and hold object
-not present in Old World monkeys, present in most New world monkeys
New World monkeys also have flat noses & tend to be arboreal
Anthropoids 1: Gibbons, Orangutangs and African Apes
Lack tails
• Gibbons: smaller than other apes, mostly arboreal
• Orangutangs: too large to cross tree by the branches, must go down to the ground
• African Apes (incl. gorillas, chimpanzees, and hominids)
Anthropoids 2: Ardipithecus—>Australopithecus
all extinct
Brains ~35% size of modern human brain
Lucy
Bipedalism evolved before brains fully evolved
Anthropoids 3: Early Homo
Homo habilis
- in Africa, 2.5-1.5 MYA
- first tool use 2 MYA
- Shorter jaw, bigger brain
Homo erectus —“standing”
- first leave Africa (spread to Eurasia)
- first fire use
-1.6 MYA – 250,000 YA
- As large as modern humans, but
smaller brain, thick skull
Anthropoids 3: Recent Homo
Homo neanderthalensis
• coexisted w/ H. sapiens
• disappeared ~30,000 YA, possibly due to extermination by H. sapiens
• short, stalky but powerful build
• similar brain size with H. sapiens, but less smart
Homo sapiens
• ~0.2 MYA also arose in Africa
• also spread out of Africa across Eurasia and to rest of world
• Larger brains than early species, favouring increasingly complex social life
Mammalian Nervous System
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
Cerebrum—Cerebral cortex
Enlarged in primates
2 hemisphere: Left control right, right control left
Cerebral cortex: top layer, rich in cell bodies, grooves and ridges increase surface area
- Frontal lobe: personality
- Temporal lobe: facial recognition, hearing
- Parietal lobe: language on the left, spatial and visual on the right
- Occipital lobe: vision center
Other structures in brain
-Cerebellum: coordination of complex motor patterns
-Brain stem: information relay, autonomic control of heart, lungs, digestive system
-Diencephalon: control of homeostasis, information relay
Lambic system-大脑边缘系统
Include amygdala (emotion center), hippocampus and nucleus accumbens
Responsible for basic physiological drives like hunger, thirst, emotions, long-term memory
