Tuesday 4/12 Learning Goal: Describe the characteristics and special adaptations of amphibians Warm up: What is an amphibian? Homework: Bring coloring supplies this week. Bring disposable gloves for frog dissection on Monday! Test on 11.3 & 11.4 on Monday 4/25

Chapter 11 Section 3 Amphibians

What is an amphibian? Examples: frog, salamanders, toads Vertebrate Ectotherm Early life spent in water Most amphibians spend their adulthood on land Return to water to reproduce

Two major groups Groups of Amphibians Salamanders: keep their tails Frogs/Toads: lose their tails

Reproduction and Development Amphibian: double life Eggs are fertilized internally in most salamanders Eggs are fertilized externally in most frog/toads Fertilized eggs develop in water, larvae emerge from eggs, begin a free swimming, fishlike life Tadpole: larva of a frog or toad Salamander Metamorphosis Larvae look like adults and lose gills Less dramatic

Frog Metamorphosis

Living on Land Respiratory and circulatory systems of adult amphibians are adapted for life on land Adaptations for obtaining food and moving Obtaining Oxygen Amphibian larvae use gills to obtain oxygen in water Lose gills during metamorphosis Lungs Organs of air-breathing vertebrates in which oxygen gas and carbon dioxide gas are exchanged Oxygen also exchanged through skin

Circulatory system Tadpole: Single loop and a heart with two chambers (like a fish) Adult amphibians: two loops and a heart with three chambers Atria: two upper chambers of a heart that receive blood Oxygen rich and oxygen poor blood Ventricle: blood moves into lower chamber pumps out to the lungs and body Blood mixes here

Obtaining food Tadpoles: herbivores Salamanders, frogs, toads: carnivores Frog and toads wait for their prey to come close Salamanders stalk and ambush their prey Frogs and toads have camouflage skin helps obtain food and conceal from prey

Movement Adult amphibians have strong skeletons and muscular limbs Frogs and toads have large legs for leaping and can absorb shock of landing

Amphibians in Danger Habitat: specific environment in which it lives Destruction of habitats is causing populations of these animals to decrease Amphibians are sensitive to changes in environment Delicate skin Eggs do not have shells