Chapter 17: The Early Tetrapods & Modern Amphibians Flashcards
What types of organisms are considered Amniotes?
Nonavian reptiles, birds & mammals
What are the only living vertebrates that have a transition from water to land?
Amphibians
What is Ontogeny?
Organismal Development
What is Phylogeny?
Evolutionary History
Amphibians are Quasiterristrial. What does this mean?
They hover between aquatic and terrestrial environments and never stray far from water
What is considered the most dramatic event in animal evolution?
The amphibians transition from water to land
List some important physical differences between water and land ( + details) (4)
Oxygen content- more abundant in air.
Fluid Density- air is less buoyant
Temperature Regulation- air fluctuates in temp more than water
Habitat Diversity- amphibians had to evolve in almost every organ system to survive.
The Sporacular Tract in Tetrapods is said to have developed from what structure?
Swim Bladder
What are the 3 groups are Modern Amphibians?
Anurans (Frogs), Salamanders, & Caecilians
In Modern Amphibians aquatic eggs will hatch revealing what? (specific)
Aquatic larvae with gills
During the Metamorphosis of Aquatic amphibian larvae what happens
Gills are lost, and lungs form requiring cutaneous respiration
Modern Amphibians are Ecotherms, what does this mean?
Their body temperature matches environmental temperature
Where are Modern Amphibian eggs laid? Why?
In or near water, to avoid desiccation (drying out)
How many Caecilians are there? Families? Species?
10 families with 215 species
Where are Caecilians located?
Tropical habitats, terrestrial, legless
Describe Caecilian vision?
Greatly reduced or lost eyes (blind)
Caecilians are Fossorial, would does this mean?
They are burrowing organisms
What do Caecilians eat?
Termites, earthworms, insects (small or elongated prey)
How many Salamanders are there? Families? Species?
10 families with 765 species
How do Salamanders move?
Walking trot gait similar to early tetrapods. Combine lateral undulations with leg movement
Salamanders are almost entirely limited to the ____
Northern Hemisphere
There are more species of Salamanders in _____ (state) than all of Europe and Asia combined.
Tennesse
How do most Salamanders reproduce?
Internal Fertilization- eggs laid in water or moist place
Describe the development of Terrestrial species of Salamanders
Direct Development; no larval stage
In general the main method of gas exchange in Salamanders is _____.
Cutaneous respiration
Salamanders have ____ when aquatic
gills
_____ are present at birth in Salamanders but later become primary means of respiration
Lungs
How many Anurans (Frogs) are there? Families? Species?
Over 50 families with over 7,350 species
True/False: Anurans are found on every continent
False; they are not found on Antartica
What is the distinct larval stage of Anurans?
Tadpoles
Many anuran species have a ____ which is a posterior fused vertebrae for jumping.
urostyle
What kind of tongue do anurans have?
Viscoelastic Tongue
Describe the function of a Viscoelastic Tongue
Uses a catapult mechanism to project tongue out to trap prey and carry it back to their mouth
What is unique about a Horned Toads’ tongue?
They have sticky saliva that has an adhesive strength greater than their body weights
How do Anurans communicate during mating season?
Advertisement calls; used to announce prescence and attract females
Females only recognize conspecific males’ calls, what does this mean?
They only recognize the Advertisement calls of males of the same species as themselves
______ is the ancestral reproduction method for anurans
External Fertilization
What is the function of an Amplexus?
Allows male to hold onto female and wait for her to release eggs so he can fertilize them
Do Anurans demonstrate parental care?
Yes, adults of many species guard and protect their eggs
