During the U.K.'s spring months of February and March, many fresh water ponds are occupied by one or more species of amphibian. Each male will try and claim a female. Those males who are successful will fertilize up to four thousand eggs as the female lays them into the shallower water, often within clumps of aquatic plants.
The fertilized eggs are just the first stage in a remarkable transformation called metamorphosis. This describes the process of change from egg to tadpole (the larval stage), through to adult amphibian.
Many of the eggs which are laid will hatch into tiny tadpoles with dark, oval bodies and a waving tail which propels them through the water. At this stage, they do not resemble the parents in any way and only a small proportion of the tadpoles will ever reach adulthood. Many will be eaten by other creatures or die of disease.
At first the tadpoles eat the remaining egg gel from which they hatched. They then eat submerged vegetable matter whilst absorbing oxygen directly from the water using their gills (fish also use gills to extract oxygen from the water). As they grow in size, lungs will develop inside the tadpoles and they will then begin to visit the surface in order to breathe in some of their oxygen from the air. Eventually the diet becomes more carnivorous as the tadpole will start eating small invertebrates in the water.
As their bodies continue to grow, legs will sprout out and in frogs and toads the tail will be reduced in size. From now on, the tadpoles will become more adult like as time passes. Eventually the gills will disappear and the body changes shape into that of a miniature adult. Frog and toad tadpoles will lose their tails all together. At this stage they normally leave the water. In Britain, most of these changes take place during a 4-5 month period so that by August each year, many British amphibians have completed their development from egg to tiny adult.
Some ponds become home to many thousands of toads and frogs in spring time when mating takes place. One such location is at the Woodland Education Centre, situated in East Devon, South West England. On only a few nights, visitors to the reserve are treated to a natural spectacle of vision and sound. Thousands of mating toads can be heard and seen within the Centre's ponds and lake.
The typical life cycle of an amphibian is egg, larva stage, a brief metamorphic period and then a multi-year life on land.
Metamorphosis
In the early stages of development, amphibians live in the water they breathe with gills as an adult an amphibian lives on land and uses lungs to breathe.
During a battalion relief-in-place cermony which of the following events occurs after the hours to the nation?
A supernova occurs at the end of a massive star's life cycle.
Systolic Pressure occurs during ventricular ejection.Diastolic Pressure occurs during ventricular relaxation.
The tadpole is the stage in which most growth occurs. This is the stage when back legs are front legs are grown.
Metamorphosis is a change in form and physiology that occurs during the development of an insect.
What occurs during nondisjunction
For a person to know which of the following events occurs during the Calvin cycle reactions they need to know what the events are. If the events are not listed they will not know which will be the answer.
Speciation occurs during the evolutionary development, or phylogeny, of a species. In which of the following situations will speciation occur
Cell plate formation occurs during cytokinesis.
When an interrupt occurs, the address following the current instruction is stored on the stack.
the word "amphibian" comes from two Greek words: amphiwhich means both and bios which means life. This refers to the fact that all amphibians are hatched from eggs in water and live in water until metamorphosis occurs and they can live on land.