Amphibians like frogs and toads are some of the earliest living vertebrates that evolved during the Devonian period. Many amphibian types went extinct over time, but those still living today include frogs, toads, salamanders and newts. Frogs are commonly used in laboratories to study anatomy, behavior and evolution. Their reproduction involves external fertilization of jelly-like eggs. As tadpoles, they have tails and gills but later develop lungs and legs to live on land as adults. Frogs play an important role as predators in the food chain, eating insects.

1. Background of group, Other organisms
found in group, Extinct or Endangered, and
What is their importance to our lives
frogs and toads
Amphibians are one of the oldest living classes of
vertebrates. They evolved during the Devonian Period, but many
Amphibians
of the types of amphibians went extinct over time. The
amphibians that live today include frogs, toads, salamanders,
newts, and caecilians. Caecilians resemble earthworms or
snakes, they live underground and are widely unknown
amphibians. The frogs are used as laboratory specimens for the
study of anatomy, behavior, ecology, and evolution. They are also
food for several human cultures. Amphibians are no longer
present in some areas, but in other regions the population is
stable and growing. They are found all over the world except in
Antarctica and Greenland.
Nutrition, Reproduction, Response to stimuli,
Adaptation, Regulation, and Place in food
chain
Frogs reproduction is sexually. The eggs are fertilized outside the
mother’s body. She lays the eggs, which are jellylike and the father
comes and fertilizes them. They adapt from living in water to living
on land. When they lived in water they were known as tadpoles and
they had tales and no legs. After half of their life was lived in water
now they become adults and live on land, but still go in the water.
When they become adults they lose their tails and grow legs. They do
not have their gills anymore and they now have lungs. Their
response to stimuli is they hear through the tympanic membrane or
eardrum. The external stimulus of sound, the tympanic membrane
vibrates and sends sound waves deeper within the skull. In the food
Shayla Brink chain they are secondary consumers. Frogs and toads are carnivores;
they eat crickets, flies, and mostly insects. By flickr user brian.gratwcke
Transportation, General structure, and What
“oddball” exists
Frogs and toads structure is different than most amphibians because
they do not have a tail as an adult and their legs are more suited to jump
than walking. They have legs that specialize in jumping and the metatarsals By flickr user paulb4uk
have become elongated to add to the leg length and allow the frog to push
against the ground for longer during a jump. The muscular system has been
modified from their ancestors, so while jumping with only a few muscles
remaining to bring the limb back in the staring position and maintain
posture. Also, the muscles have become larger accounting for over 17% of
the total mass of the frog. Their transportation externally is they swim or
hop, jump, and leap. Internally they transport by a closed circulatory
system. This is an organ system that passes nutrients, gases, hormones, By flickr user rainforest harley
blood cells, etc. to and from cells in their bodies.
Respiration and The type of symmetry
Their respiration in water is they breathe through gills in their skin. On
land when they are adult the frog uses its lung for breathing like humans
do. The symmetry of the frog and toad is bilateral, which is if you would
cut it in half long ways both sides would look the same.