Amphibians Life on Land & in the Water
Amphibians Objectives
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Describe the evolutionary path and characteristics that distinguish amphibians from other vertebrates.
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Outline the steps of a frog’s life cycle.
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Provide examples of amphibians, including their habitats and representative species.
Amphibians are an excellent model for studying life stages.
We’ll start with a quick overview of amphibian characteristics, followed by a little more depth and links to life stages.
This video focuses in on key features that separate amphibians from other vertebrates.
Eryops, one of the earliest amphibians, is believed to have reached 10 feet in length.
Frogs and toads are the most common amphibians, but their names can be misleading.
Terminology is often constructed for ease of communication, but misconceptions can result.
One of the first biology lessons in elementary grades is on the frog life cycle.
Fill in a few gaps and learn why this is such a popular topic.
Tadpoles are breathing with gills underwater, although they are not always found in typical ponds and streams. See them in a more extreme location in this video.
Amphibians are not as frequently kept as pets as other vertebrates for a variety of reasons. This includes bans on sales due to over-collection and also concerns that released pets could become invasive species in new locations. Additionally, not all amphibians are easy to breed or maintain in captivity.
One relatively easy to care for amphibian is the freshwater Dwarf African Frog (Hymenochirus curtipes). The adults stay submerged, rising to the water surface to breath with their lungs.
New frogs showing color variation. The albino frog has two recessive alleles, which shut down another gene that would typically code for pigment production.
One month later, the frogs have grown. Notice the size of their abdomens. They require a variety of live foods for healthy growth and longevity.
A pet increasing in popularity is the Axolotl, also known as the “Mexican Walking Fish.” This is a large salamander that stays aquatic as an adult, relying on external gills for breathing.
Axolotls are close to extinction in the wild due to loss of habitat and water pollution. They require careful care in captivity and efforts are underway to try to save the species; in part due to their unique genome which has 10 times the genetic information as the human genome.
Axolotls have have a variety of naturally occurring colors due to variation in alleles. These animals are separated to minimize the chance of injury.
This is a genetically engineered neon axotoyl. It has genes from a jellyfish, which enables it to produce fluorescent proteins not naturally found in this species.
The red-eyed tree frog is one of the best known amphibian species.
Now that you have completed this section, list five characteristics of amphibians like this frog.
Portfolio Update
At this point you have accumulated numerous quiz answers and media pieces. This video recommends matching completed work with the nine course outcomes.
If you are interested in revisiting any of the portfolio videos that were in previous modules, they are also located on a single page for easy reference:
The next section explores one of the most interesting aspects of life: how a fertilized egg can develop into. an entire organism.
Check your knowledge. Can you:
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Describe the evolutionary path and characteristics that distinguish amphibians from other vertebrates.
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Outline the steps of a frog’s life cycle.
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Provide examples of amphibians, including their habitats and representative species.
Go back to the Life Stages Page
Go forward to the Development Page
Life Cycles Lecture Guide Contents
The material from this guide and corresponding lecture is assessed on the weekly quiz.
Back to Development
Module 6
This Guide
Life Cycles
