Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Amphibians are among the best examples for studying how developmental patterns reveal evolutionary history. Although adult frogs and salamanders look quite different, their embryos and early larvae share striking similarities - and both show traits that connect them to fish ancestors.
Frog embryos begin life in water, forming gill arches, a notochord, and a tail. Salamander embryos develop nearly the same way, even though adult salamanders retain gills longer. In early stages, both species have structures used for swimming, including a muscular tail and lateral line sensory cells like those in fish.
As development proceeds, differences emerge: frogs begin to form hind limbs first, while salamanders develop front limbs earlier. By late larval stages, frogs start resorbing their tails and developing lungs, while salamanders often keep their tails and gills into adulthood.
Scientists use microscopic and pictorial data from frog and salamander embryos to explore evolutionary connections. The sequence of developmental changes provides clues to how early vertebrates transitioned from fully aquatic to partly terrestrial lifestyles. For instance, both species briefly form internal gills similar to fish, then develop lungs and legs - showing a living reflection of the ancient transition from water to land.
Modern techniques, such as time-lapse microscopy and genetic analysis, show that both species activate the same Hox gene clusters to pattern their limbs, but small differences in gene timing cause distinct adult body forms. This demonstrates how evolution reuses the same developmental toolkit across species, producing variation through gradual change.
Graph of Information - Figure 1.
Graph of Information - Figure 2.
Figure 3.
Figure 4.
Using Table 1, compare gill development in frogs and salamanders from early embryo to adult stages. What pattern do you observe?
Explain why both frogs and salamanders show early larval structures similar to fish, even though they become very different adults.
According to Table 2, which species begins using lungs first?
Based on the reading, which developmental process explains how frogs lose tails and gills, while salamanders retain them?
Does the developmental data support the claim that frogs and salamanders share evolutionary relationships with both aquatic and terrestrial vertebrates?
Respond using Claim, Evidence, and Reasoning.
Using Table 2, compare the timing of limb appearance in frogs and salamanders. What does this difference suggest about how their body plans diverge during development?