Lecture 21: Vertebrates, Fish, & Amphibians Flashcards
vertebrate traits
- all have heads
- endoskeletons supported by vertebrate
- internal organs
- circulatory systems
head in vertebrates
- make us all look similar
- it’s an interior skull (made of bone/cartilage) containing a brain
- head has a concentration of sensory organs (eyes, ears, nose and/or mouth)
internal organs in vertebrates
- suspended in coelom
- includes lungs, liver, kidney, stomach, heart, and endocrine system
endoskeleton supported by vertebrate in vertebrates
- protects dorsal nerve cord (which allows brain to direct movements)
- it’s made of cartilage or bone which is advantageous over chitin bc it grows w you and allows us to be big
circulatory system in vertebrate
-pumped by a muscular heart
hagfish
- the outgroup to vertebrates, but now we realize they’re closely related to lamprey
- may be the 1st vertebrates since lamprey are def. vertebrate (collectively the cyclostomes)
why are people hesitant about hagfish being a vertebrate?
- they have 3 accessory hearts
- a weak circulatory system
- a partial skull with no cerebrum or cerebellum
vertebrate groups
- fish
- amphibians
- mammals
- reptiles
- birds
fish diversity
- only fully aquatic group, most diverse group of vertebrates
- certain adaptations from them allowed for the invasion of land by amphibians
- types: sea horses/ leafy sea dragon, tunas, eels, manta rays
five traits of all fish
- jaws
- paired appendages
- internal gills
- single loop blood circulation
- amino acid deficiencies
jaws on fish
- allow them to catch and eat larger prey
- supports a larger organism
paired appendages on a fish
- pectoral pair of fins and pelvic pair at hips
- helps stabilize and propel them
- eventually evolve to be jointed which gives us our appendages
internal gills on fish
-allow them to extract oxygen from water
single loop blood circulation in fish
- blood is pumped from heart to gills (where it gets oxygen), then to the rest of the body, then back to the heart
- our circulatory system is double looped.
amino acid deficiencies in fish
- unable to synthesize 3 different amino acids, so must get them through food
- they’ve passed this onto the rest of invertebrate
agnathans
-no jaw
extinct placoderms
- lived during early time of jaws
- after extinct, replaced with sharks
modern gnathostomes
-“jaw mouths”
sharks and rays
- they have lightweight and strong skeletons made of cartilage
- have very efficient jaws and were the first to evolve teeth
- the teeth aren’t embedded in their jaws and they have lots of rows of them
- after Permian extinction, you see them and rays get big
- they diverge from the rest and that’s when you start seeing bony fish
cartilage vs. bony
- cartilage makes organisms fast and agile and bone is heavy but strong and gives power of movement
- has allowed the transition to land to occur
importance of teeth
-allows them to chew their food, eat larger prey, and increase the nutrients they take in from their food
swim bladders
-used to counter heavy bony skeleton. Can increase or decrease air in it, allows fish to control position in water and remain buoyant
ray-finned fish
- have parallel bony rays that stiffen their fins and their internal muscles control their fin movements
- they move their fins in concert
lobe-finned fish
- only 8 extant species
- have muscular lobes and central core of bones in fleshy lobe
- only have the ray bones in the tips of their fins
- types: coelacanths, lungfish
ichthyostega
- one of the earliest amphibian fossils we have
- came after Tiktaalik
- moved a lot like a seal
- had better smell/hearing than fish
challenges of land Invasion
- moving heavy bodies
- replacing gills
- increasing oxygen intake and delivery to larger muscles for walking
- preventing drying out of eggs and body
amphibians
- “double life”, they only partially solved the challenges of land invasion
- both aquatic and terrestrial
traits shared by modern amphibians
- legs
- lungs
- cutaneous respiration
- pulmonary veins
- partially divided hearts
legs on amphibians
-for walking
lungs in amphibians
-have less surface area for O2 than in mammals or reptiles, so they supplement O2 intake
cutaneous respiration in amphibians
- how they supplement oxygen intake
- breathing through skin in order to get enough oxygen and get rid of enough carbon dioxide
pulmonary veins in amphibians
- lung veins return deoxygenated blood to heart to pump to rest of body
- stronger flow once blood is oxygenated to get blood to the rest of the body
partially divided hearts in amphibians
-what gets pumped out to the rest of the body isn’t fully oxygenated bc there’s a little hole that mixes oxygenated and non-oxygenated
major amphibian groups
- frogs
- salamanders
- caecilians
age of amphibians
- when amphibians ruled terrestrial habitats
- grew to be very large and developed thick skin and body armor which means they must have depended on their lungs entirely
- the rise of reptiles led to the decline of amphibians
frogs
-have smooth/moist skin and long legs
toads
-have dry/bumpy skin and short legs
what frogs and toads have in common
-both don’t have tails, live in a wide range of environments and lay eggs
salamanders
- elongated bodies and tails
- big range in size
- tend to live in moist place
- young look very similar to adults
mud puppies
-group of salamanders that is fully aquatic
caecilians
- have lost limbs
- live in the tropics
- they burrow
- are worm-like
- have jaw, skull, vertebrate, and brains
eryops megacephalus
-big amphibian from age of amphibians
