Highest_priority_cards_10_-_all_duplicates Flashcards
Q: Where are amphibians classified taxonomically?
Amphibians are one of the five (actually >5 because multiple fish classes) classes in the Vertebrata subphylum.
Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Amphibia.
Q: What are the three living orders of Amphibians
Frogs and toads, order Anura
Salamanders and Newts, order Caudata
Caecilians, order Gymnophiona (limbless, worm/snake shaped, small/nonexistent eyes)
Q: What was the first Class of vertebrates that stepped out onto land? How long were they the only vertebrates on Earth? (Or maybe only on land? Check on this.)
Amphibians
60 M years
Q: Adaptations that allowed amphibians to stay out of the water for longer periods
lungs improved
skeletons became heavier and stronger
Q: “Disadvantages” of amphibians that kept them reliant on water
Gas-permeable skin, which serves to aid their inefficient lungs, requires moisture.
Jelly like eggs cannot survive out of water.
Q: Vertebrate
Animal with an encased nervous system including a well-developed brain and a nerve cord that runs through the (internal) spinal column or backbone.
Have a muscular system and an internal skeleton that supports and protects internal organs, provides mobility.
Highly developed nervous system; vertebrates can react very quickly to changes in their surroundings, giving them a competitive edge
Often larger and have more complex bodies than invertebrates.
The most advanced organisms on Earth.
Subphylum of the Chordata phylum
Q: Endoskeleton
an internal skeleton, such as the bony or cartilaginous skeleton of vertebrates.
Q: Advantages of an endoskeleton over exoskeleton
Endoskeleton can grow with the organism. No molting.
Provides greater flexibility in movement.
Will support greater weight without becoming too heavy for the organism.
Q: Characteristics of amphibians
Vertebrates
Ectothermic
Life cycle tied to water, with eggs and larvae found in freshwater. Require cool, moist environments for their eggs and their skin. Naked skin (it lacks fur, feathers, or scales)
Larvae have gills and adults have lungs
Most adults are insectivorous; juveniles are herbivorous
Mainly temperate and tropical species
Adults have a three-chambered heart. Tadpoles have two-chambered heart.
Note: The word amphibian comes from the Greek amphi and bios, meaning “double life”, that is, they can live or function on land and in freshwater.
Q: Ectothermic
any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface.
Q: Nictitating membrane
A transparent or translucent third eyelid present in some animals (including amphibians) that can be drawn across the eye for protection and to moisten it while maintaining visibility.
Q: Amphibian eggs
gelatinous egg
similar to fish egg
no shell, deposited in water or other damp location (damp soil, on a certain plant, on mom’s back) to prevent from drying out
series of jellylike layers that protect the developing embryo from desiccation, pathogens and, to a limited extent, predators
Oxygen and carbon dioxide diffuse passively through outer membrane
Q: Metamorphosis in amphibians
All amphibians exhibit complete metamorphosis: egg, aquatic larval form w/gills, adult w/lungs.
Amphibians are the only four-limbed or land vertebrate that go through a complete metamorphosis.
Full metamorphosis averages 12-16 weeks, time span greatly affected by water temperature and food supply.
Recall a benefit of metamorphosis: adults and young fill different niches and don’t compete.
Q: One way amphibians are important to ecosystems
Crucial role in food web, especially as predators and as prey for other animals.
Loss of amphibians would result in disastrous ecosystem-wide effects in terrestrial and aquatic environments.
Q: Threats to amphibians
Pesticide runoff from farms, pharmaceuticals flushed down the toilet have contributed to defects and mutations such as multiple or deformed legs.
Chytridiomycosis (or chytrid fungus)- fatal disease affecting amphibian populations worldwide; has caused decline or extinction of many species.
Invasive, introduced species out-compete native species to the point of extinction. Marine toad introduced to Australia from Hawaii; prolific breeder; steadily increased its range.
Q: List the orders of living reptiles
Turtles (Testudines)
Crocodilians (Crocodilia)
Lizards and snakes (Squamata)- largest order
Tuatara (Rhynchocephalia)
Q: Where are reptiles classified taxonomically?
Reptiles are one of the five (actually >5 because multiple fish classes) classes in the Vertebrata subphylum.
Kingdom: Animalia; Phylum: Chordata; Subphylum: Vertebrata; Class: Reptilia.
Q: What differentiates reptiles from amphibians? (Hint: think about characteristics that adapted them to life on land)
Evolution of stronger, more effective jaw mechanisms.
Evolution of more effective locomotion on land.
Development of the amniotic egg, lay soft-shelled eggs on land.
Development of scales for water tight skin. Dry scaly skin.
Q: Semipermeable
(of a membrane) Allowing certain molecules, but not others, to pass through.
Q: Reptile characteristics
Ectothermic
Vertebrates
Tough, water-tight skin covered in scales (made of keratin)
Scales may be small and overlapping or large and adjoining, cannot be replaced individually (Unlike in fish), must shed skin with growth
Mainly egg laying, leathery shell, eggs must be laid on land
Q: Are there any internal processes reptiles can use in temperature regulation
Reptiles use the ability to shift blood between the body and the lungs to accelerate heating and slow cooling.
Q: First group of animals to have embryo encased in shell
Reptiles
Q: Reptile eggs
Amniotic egg
Semipermeable, leathery shell; protects from predators, pathogens, damage, drying
Semi-permeable shell allowing gas exchange while retaining essential fluids
Must be laid on land
Contains an amnion- fluid-filled sac (membrane) that cushions and protects the embryo inside.
A yolk provides the animal with food
Some reptiles give live birth
Q: Significance of evolution of amniotic egg
Reproduction no longer had to take place in water. Animals emerged from the oceans to life on the land.
Eggs could “breathe” and cope with wastes, eliminating the need for a larval stage thereby allowing the embryos to evolve into larger forms and mature further prior to hatching.
Cost: external fertilization of shelled eggs not possible, internal fertilization developed in reptiles.
Q: Which groups of animals have amniotic eggs
Reptiles, birds, and mammals all have amniotic eggs
Q: Reptile heart
All reptiles except crocodilians have 3-chambered heart with single ventricle.
Heart can adjust proportion of blood that goes to body versus lungs– used to accelerate heating and slow cooling.
Three-chambered heart limits ability to breath while chasing down prey. Hence ambush predators.
The fourth chamber of heart improved the crocodiles ability to actively hunt down prey.
Q: Reptile teeth, ingestion, waste
Generally simple and conical (peg-like).
Uniform in shape and size throughout jaw (homodont). Vary slightly in size.
Upper and lower tooth rows do not contact one another.
Continuously shed and replaced throughout life.
Used for killing and holding.
Swallow food whole.
Waste is uric acid, which is low in water content, reducing water loss.
Q: By what characteristic are modern reptiles split into subclasses? What is notable about the evolution of these characteristics?
-Four subclasses based on number and position of temporal fenestrae, openings in the sides of the skull behind the eyes.
-Early in reptile history, changes occurred in muscle attachment to the lower jaws and the skull in amniotes having to do w/ development of stronger and more efficient jaw muscles and a diversification in what they ate. Allowed more powerful and faster bites.
-Three patterns of holes (fenestrae) in the temporal region of the skull, just behind the eye. (details on separate card)
-Provided space for the large muscles needed for feeding when shifting from an aquatic environment to a terrestrial one where the vegetation was more coarse.
Q: Fenestrae
a small opening in the bone
Q: Three patterns of holes that developed in skulls of early amniotes.
-Different patterns of fenestrae in temporal region of skull behind eye
-0 temporal fenestrae: anapsids- turtles, tortoises and terrapins
-1 temporal fenestrae: synapsids- evolved into mammals
-2 temporal fenestrae: diapsids- birds and major reptiles (lizards and snakes, tuatara, alligators and crocodiles, dinosaurs)
Q: How are modern reptiles classified?
Temporal fenestrae, or lack thereof.
Most have two fenestrae with the exception of the turtles, tortoises, and terrapins, who lack fenestrae.
Q: Notable skull characteristics of reptiles besides teeth
Lower jaw is composed of several different bones which hinge on quadrate bone of the skull and the angular bone of the jaw.
Only one bone of the middle ear, the stapes.
The reptilian skull is attached to the spine by a single point of contact, the occipital condyle.
Q: Reptile senses
Light:
-Eyes usually large and well developed, though may be reduced in burrowing species.
-All but the snakes have eyelids.
-Lizards and snakes have light sensitive organ called the “parietal eye” on top of the head which looks like a clear scale.
Smell:
-Usually very sensitive
-Snakes and most lizards have “Jacobson’s organ” on roof of mouth. Use tongue to collect molecules in air and brush them over the organ. Tongue fork helps decipher location.
Hearing:
-Most have poor hearing and usually pick up vibrations through skull against the ground
Taste:
-not well developed
Heat:
-Some snakes such as vipers, boas, and pythons have heat sensing pits around jaws for locating endothermic prey
Q: Jacobson’s Organ
an organ of chemoreception that is part of the olfactory system of amphibians, reptiles, and mammals
Q: Roles of reptiles in ecosystems; also specific benefits to humans
Vital roles in the functioning of ecosystems
As predators they control their prey populations (and many crocodilians are keystone species)
- Keep rodent populations under control; rodents transmit diseases to people
As prey themselves they provide a vital food source for birds and mammals.
Q: Threats to reptiles
Pet trade; taken from wild and require specialized care (food, lighting, heating, exercise, long-lived, difficult to find a vet).
Human perception that they’re dangerous; unfounded fears
Human perception that they’re of little environmental or economic value
