week 11-tay Flashcards
how many years ago did fish evolve?
500 million years ago
what is the common ancestor for all fish/mammals?
ancestral chordates
example of uro-chordates
tunicates
example of cephalo-chordates
lancelets
first vertebrae fish
jawless fish
- no bck
cartilaginous fish
have jaws only
- no back
bony skeleton fish
bony fishes and lobe-finned fishes
lobe-finned fish
have appendages - like arms that move
lung development
frogs
development of the amniotic egg
reptiles and birds
development of mammary glands
mammals
lancelets
the closest species to the common chordate ancestor
- like living fossils - contain a notochord but no vertebrae
- benthic filter feeders
benthic filter feeder
live in (or near) ocean floor and feed by filtering small particles from the water
fish
- most abundant and diverse vertebraes
- use gils for breathing and fins for swimming
- ectothermic (mostly)
- great diversity - size, shape, speed of movement, lifestyles and habitat
ectothermic
don’t regulate body temperature - it changes with environment
what fish are not ecothermic?
some tuna and sharks can regulate their body heat to some degree with metabolism
jawless fish
- no paired appendages to aid in locomotion (get around by wiggling their tails)
- round sucking mouths
- some are parasitic (predatory)
2 types of jawless fish
- lampreys
- hagfish
parasitic function fo jawless fish
they stick their round sucking mouth into the side of a fish and chew away on it
sea lamprey
- no scales
- large eyes, one nostril on top of head
- 7 gill pores
- cartilaginous skeleton
- can adapt to both freshwater and saltwater
where can you find sea lamprey?
oceans
- they have also invaded the Great Lakes (stated in 1800’s in Lake Ontario)
hagfish
- some are predatory, but most are scavengers - no jaws, but lots of teeth
- slimy and tie themselves into knots
- body is covered in pores that secretes fibrous slime (mucus)
mucus/slime produced by hagfish
- when slime combined with water it will expand - up to 20L of slime
- used as a defence mechanism
- they tie themselves into a knot to scape off the slime
what is the slime hagfish produce composed of?
protein and mucus
uses for slime produced by hagfish
- fabric
- bandages
- egg-white substitute and other culinary delights
how fast do hagfish release slime?
less than half a second
- create a litre of slime, and release 40 mg of mucus and protein
cartilaginous fish - sharks
- living fossils
- some species are apex predators in many marine food webs (due to jaw style)
- variable in size and appearance
sharks as living fossils
there is fossil evidence up to 450 million years ago
body plan of a shark
- no swim bladder
- wing-shaped body, fins that push water down
- no bone, only cartilage
- lightweight liver
- heterocercal fin (asymmetrical tail fin lobes)
swim bladder - sharks
organ that allows the exchange of gas
- sharks don’t have it so they swim around continuously so they don;t sink
purpose of the body plan of a shark
give it lift so it maintains buoyancy
heterocercal fin of sharks
asymmetrical where top is longer than bottom
- allows them to adjust speed
pectoral fin of sharks
pushes water downwards, to lift the shark up
how many species of sharks are alive today?
> 400
shark size
variable
- 80% are less than 1.6 m long (small)
ex. dwarf lantern shark
dwarf lantern shark
- 22cm long
- bioluminescent
whale shark
up to 18.8 cm
- avg. weight 19 tonnes
- eats mostly plankton
sharks skin
covered by dermal denticles (placoid scales)
- attachments for swimming muscles, saves energy
- reduces turbulence while swimming (increases speed)
- do not grow, added in number as animal increases in size
dermal denticles - shark
similar to vertebrae teeth
- pulp in centre, covered in dentine, then enamel is outermost
shark teeth
- embedded in gums - not affixed to jaw
- constantly replaced - multiple rows of replacement teeth
- tooth shape reflects diet
- some parasitic species (cookie cutter shark)
finer shark teeth
eat smaller fish
- cephalopods
broader shark teeth
eat larger fish
- marine mammals
cartilaginous fish - batoids
flat bodies with enlarged pectoral fins attached to head
- also covered in dermal denticles
- presence of 5 gill slits on ventral surface
2 types of batoids
- rays
- skates
manta rays
- largest rays (up to 9m wide)
- found in open ocean, and reefs
- filter feeders - zooplankton
- visit cleaning station where parasites are picked off
- 2 species
manta rays - filter feeders
eat by pushing zooplankton into their mouth
- cephalic lobes help guide zooplankton into their mouth (acts like nets)
stingray
- often nektobenthic
- mouth on bottom
- prey on fish, gastropods, crustaceans
- flat teeth for crushing shells
- long tails
- over 200 species
nektobenthic
spend a lot of time on bottom
- but also in open ocean
purpose of mouth on bottom of stingrays
built for eating things from the benthic environment
- bottom of ocean
long tails of stingrays
venomous barbs
- defense mechanism
bony fish
- largest group of vertebrates
- economically import
- strong lightweight skeleton
- use gills to extract oxygen from seawater
- most are ectothermic
- heterotrophic
how long ago did bony fish first appear?
420 million years ago
why are bony fish economically important?
make up a huge amount of protein sources in the human diets
phenotype of bony fish
highly variable shape, size and appearance
- vary based on that they eat
shapes of bony fish
- anguiliform (eel shape)
- fusiform (bullet or torpedo shape)
- depressiform (broad shape and flat top to bottom)
- compressiform (tall, thin, shape and flat side to side)
anguiliform shape - adapted function
maneuvering in crevasses and tight spaces
- allows rapid swimming - ambush predators
fusiform shape - adapted function
lowering frictional resistance in fast swimmers
- most common - fastest shape
depressiform shape - adapted function
lying on or below the surface of the sand
- eyes move around
compressiform shape - adapted function
entering vertical crevices
- skinny and slender
bony fish - fins
- both paired and single (median) sins
- fins types differ for different purposes
- tail (caudal) fins
tail (caudal) fins
- primary fin used for locomotion
- caudal peduncle
caudal peduncle - bony fish
- anal/dorsal fin to tail fin
- powerful muscular region
- allows strong swimmers
types of tails on bony fish
- rounded tail
- truncated (triangular) tail
- lunate (moon shaped) tail
- forked tail
- heteroceral (taller upper lobe) tail
rounded tail - adapted function
slow swimming, accelerating, and maneuvering
truncated tail - adapted function
turning quickly
lunate tail - adapted function
continuous long distance swimming
forked tail - adapted function
rapid swimming, somewhat sustained with bursts of speed
heteroceral tail - adapted function
slow or rapid swimming with bursts of speed
- some of the fastest organisms
nekton
animals that swim
myomeres - bony fish
packages (layers) of muscle tissue attached to the vertebrae of a fish
- allow rhythmic side motion
- the part humans like to eat
how do most fish move?
propel themselves through water by moving their bodies or fins in S-shaped waves via myomeres
streamlined shaped (fusiform)
reduces drag
- produces mucus
- tail fin - 2 lobes that are the same size
blue tuna
one of the fastest and wide ranging animals in the ocean
- fusiform shape
fish - swim bladders
only in bony fish
- achieve neutral buoyancy in water
how does the swim bladder work in bony fish?
- ascend by reducing overall density - fill bladder with O2, causing a greater volume, but no increase in mass
- descend by deflating the bladder, lowering volume and sinking
physostome swim bladder
pneumatic duct connects esophagus to swim bladder
- use mouth for the rapid addition or removal of gas
physoclisti swim bladder
swim bladder not connected to esophagus
- slow addition or removal of gas
- interchange of gas in blood and gas gland
***takes longer as air must be exchanges with swim bladder through the body
bony fish and breathing underwater
- breathe dissolved O2 in water
- this happens by passing water over gills (an organ)
- O2 from water passes into gills between the lamella, into the capillaries
gill filaments
lots of surface area
- increased SA increases O2 exchange
- fish pull 80% O2 in water down to 15%
ocean sunfish
- heaviest bony fish
- one 2,300 kg and 2.7m long caught in Japan in 1996
marine reptiles
4 orders/families
4 orders/families of marine reptiles
- order: crocodies, family: crocodylidae
- order: testudinidae, family: cryptodira
- order: squamata, family: iguanidae
- order: squamata, suborder: serpentes, family: elapidae
marine reptiles
- egg-laying animals, must lay eggs on land
- breathe air - NO GILLS
- ectothermic (cold-blooded)
why must marine reptiles lay eggs on land?
egg cannot exchange O2 in the water - must exchange it through the air
sea turtles
- contain specialized salt gland - secrete excess salts (tears)
- osmoregulation
osmoregulation of the sea turtles
most organisms must actively take on, conserve, or excrete water or salts in order to maintain their internal water-mineral content
sea turtles - features head
- no teeth, have a beak-like mouth used for crushing or tearing food
- excellent eyesight underwater, short-sighted on land
- gland near eye releases excess salt and fluids - keeps eyes moist when females are laying eggs on land
what do sea turtles feed on?
jellies, some fish and crustaceans
- whatever they can crush or tear with their mouth
sea turtles - features body
- both an internal and external skeleton
- front fins used as wings for propulsion (large and sensitive to touch)
- cannot retract legs and head into shell
- back fins used to direction and stability (reverse of fish)
external shell on sea turtles
provides protection against their predators
sea turtles as exceptional navigators
- return to home beach to lay eggs - travel great distances
- use earths magnetic field to navigate
sea turtles laying eggs on land
- dig hole (up to 50 cm) with hind flippers and deposits eggs (clutch)
- can lay up to 200 eggs
- net temperature determines sex of hatchings
- only 1 in 1000 survive to adulthood
marine iguanas
only marine lizards - found on the Galapagos islands
- herbivores (algae)
- nest on land
- dive as deep as 30m and can stay underwater for up to an hour
why do marine iguanas have such large claws if they eat algae?
to grip onto the rocks underwater to eat seaweed
marine iguanas and filtering salt
salt filtered from blood
- specialized glands at nostrils to expel salt in a process like sneezing
sea snakes length
120 - 150 cm long
sea snakes features
- paddle-like tail that generated propulsion under water
- many have highly toxic venom
sea snakes respiration
cutaneous respiration used to extend dives
- up to 8 hours; typical dive is 30 minutes
- up to 30% of O2 intake in some species
cutaneous respiration
gas exchange through the skin
- not enough to allow them to stay underwater
marine mammals
- aquatic and semiaquatic mammals
- rely on marine environment for feeding
- adaptations to marine lifestyle
- inhabit many different environments
- include largest animals to have ever lived on earth
3 living groups of marine mammals (orders)
- sirenia
- cetacea
- carnivora
sirenia
manatees and dugongs
cetacea
- whales
- dolphins
- porpoises
carnivora
- seals
- sea lions
- walruses
- sea otters
- polar bears
common characteristics of marine mammals
- stream-lined body shape
- high metabolic rate coupled with insulating fat (blubber) or fur - can generate internal body heat and conserve it
- ability to collect and retain large quantities of O2
- no need for freshwater (derives water from breakdown of food)
- warm-blooded
why do marine mammals need to eat a lot?
because water (especially cold) is always sucking energy out of mammals
- requires huge amounts of energy to keep warm
sirenia - features
3 species of manatee, 1 species of dugong
- live in warm, tropical areas
- vegetarians
- sleep and graze (eat) all day
what do sirenia eat?
vegetarians - eat mostly sea grass, estuarine plants, and sometimes algae species
dugongs
in salt water
- smooth skin
- fluked tail
- broad, short snout
- downward with mouth slit for feeding
manatees
in saltwater and freshwater
- rough skin
- paddle-shaped tail
- divided upper lip, shorter snout for feeding
are manatees or dugongs larger?
manatees
who are the closest mammal relatives of Sirenia?
elephants
cetacea - 2 types
- mysticeti (toothless whales)
ex. baleen whales - odontoceti (toothed whales)
ex. porpoises an dolphins
fluke tail
horizontal tail fin, used for propulsion
- cetacea have it
who are the closest mammal relatives to cetaceans?
hippos
cetacea features
- nostrils on top
- front limps are flippers - no rear limbs
- muscular tail - pair of fin-like horizontal flukes
evolution
natural drivers of the ecosystem make changes from one organism to another
- make them better fit the environment
adaptations for deep diving of cetaceans
- specialized structures (extract up to 90% of O2 from air)
- can store O2 (blood can)
- muscles - insensitive to CO2, work without O2
- collapsable rib cages (brings in extra O2)
most extreme diving mammal
Cuvier’s beaked whale
toothless whales
also known as baleen whales
ex. blue whales and humpback
***biggest organisms
toothless whales - feeding
this group includes some of the largest animals on earth, BUT feed on some the smallest animals in the ocean (lower on the food web)
- filter feeders
filter feeding of toothless whales
strain (filter) huge amounts of ocean water through their baleen plates to capture food
- krill, zooplankton, crustaceans and small fish
humpback whales - specific feature
have baleen (keratin) in their mouth
- basically like huge amounts of “hair” that grows in the mouth
- species specific
bubble feeding of toothless whales
blow a bubble net
- fish get freaked out when they are surrounded by bubbles and the whales eat them
grey whales (toothless)
- baleen whales that feed primarily on the bottom of the ocean
- longest migratory whales or all mammals - up to 22,000km
- covered with crustaceans (barnacles)
distinctive feature of toothless whales
paired blowholes
- evolutionary migration of nose on back
toothed whales
- 90% of all whale species
- high intelligence
- one blowhole
- use echolocation to locate food (dive deep in search for food)
- torpedo-shaped bodies
- carnivorous and predatory
- apex predators, at top of food web (orcas)
examples of toothed whales
- sperm whales (speed)
- narwhal
- killer whale
- beluga whale
- cuviers beaked whales
- dolphins
- pilot whale (chase orcas away)
toothed whales - feeding
carnivorous and predatory
- have teeth to hold and position fish to aid in swallowing
hunting techniques of toothed whales (mostly orcas and dolphins)
orcas select different body parts to eat
- ex. shark livers
echolocation of toothed whales
- biological sonar echoes to locate and identify objects
- utilize low-frequency sound
- emits calls out to the environment and listens to the echoes of those calls that return from various objects (use the echoes to create a 3D picture of surroundings)
- used for hunting and navigation
sperm whales
largest whales
echolocation steps in sperm whales
- air forces through right nasal passage to “monkey lips”
- nasal passage snaps shut, producing a percussive sound (a click)
- sound travels through spermaceti organ - shape like a curved radar dish
- reflected sound is amplified and projected forward via junk
spermaceti organ of sperm whales
fatty tissue making up the skull
what do toothed whales include?
porpoises and dolphins
- differ in their faces, fins and body shapes
porpoise
- smaller and stouter
- blunt snout (nose)
- small, more triangular dorsal fin
- blunt/flat teeth
dolphin
- elongate and streamline
- longer snout (nose)
- dorsal fin - sickle shaped
- pointed teeth
high intelligence of toothed whales
they have a smaller body mass and a large brain mass
- very intelligent
2 outliers with brain size to body mass ratio
humans and dolphins
carnivora - features
- semi-aquatic
- some are pagophilic
- observe haul-out behaviour in some members (haul themselves onto land)
semi-aquatic
spend at least some time on land or sea ice to breed and bear young
pagophilic
use marine ice for hunting/habitat
what does carnivora include?
- pinnipeds
- fur seals
- true seals
- sea lions
- walruses - sea otters
- polar bears
sea otters
aquatic member of the weasel family
- among the smallest marine mammals
sea otters - features
- webbed feet
- water repellant fur - used for insulation (float on back to stay warmer)
- nostrils and eyes close in water
- bring food up to the surface and eat at the surface
sea otters - feeding
- eat over 50 types of marine life
- use tools
- eat sea urchins mostly
fur trade impact on sea otters
sea urchins eat kelp, so when the fur trade happened sea otters were not there to eat sea urchins and all the kelp was gone
pinnipeds
fin/feather foot
- haul-out mammals
- 3 families
- large sharp teeth
3 families of living pinnipeds
- walrus
- fur (eared) seals and sea lions
- true seals (earless seals)
sea lion traits
- larger in general
- social - congregate in rafts
- loud vocalizations (bark)
fur seal traits
- smaller - but greater sexual dimorphism (males a lot bigger than females)
- longer back flippers
- cold environment
mutual traits between sea lions and fur seals
- external eats; small outer flap
- long and muscular flippers
- ability to walk on all fours “walk on land”
- dense underfur
true seals
- small, webbed flippers (better and faster swimmers)
- fur covered - but use blubber for insulation (an buoyancy)
- lack external ear flaps (just tiny hole)
- quiet and solitary
leopard seal
- big (up to 590 kg, 4 m long)
- antarctic pack ice
- eat penguins, fish, squid, krill
- rare cases of attacks on humans
***observed teaching a photographer to hunt
what is the largest carnivora
elephant seal
- males: up to 4,000kg
- females: up to 1,000kg
how to fur seals feed?
- raptorial feeding
- snapping of jaws around organism - suction feeding
- suck organism in
how do leopard seals feed?
- raptorial feeding
- suction feeding
- suction filter feeding
- push water away, suck organisms in
who are the closest land mammal relatives to pinnipeds?
musteloids
- weasels, racoons, skunks, red pandas
raptorial feeding
grip and tear
- rapid jaw opening and closing
suction feeding
suck organism in
- but don’t drink salty water - so push water away as they suck
polar bear - 2 adaptations for warmth
allow travel and hunting in the oceans
1. thick fur, with hollow hairs - trap air and act as insulation
2. dark skin helps absorb heat
what are polar bears closely related to?
grizzly bears
polar bear - 4 additional adaptations
- webbed paws (paddle-like)
- powerful body and limbs for swimming and hunting
- larger teeth and thicker, curved sharp claws (gripping ice and prey too)
- ability to close nostrils for extended underwater swimming
