How come some fish evolved into egg-laying fish to reproduce and then you have whales that are mammals?

Answer 1

Evolution is a lie. Seriously, it's not in the Bible.

Answer 2

Evolution is not linear - ie, once you've come out of the sea, you won't go back. Mammals are believed to have evolved on land, but we also have bats, sloths, walruses and whales. Perhaps the whales ancestor went back into the sea or perhaps they evolved from a common ancestor that never felt the need to leave. Evolution happens when a species finds its needs (food and security) best served by entering or leaving a particular environment. For whales, the sea is a better place to be than up a tree or under a bush.

Answer 3

I don't know. I saw a dinosaur show on Discovery once. In it was a whale like mammal. They speculated that the animal had once been a land animal and had gradually evolved into an animal without feet. Damn, can you imagine how many millions of years it took for that to happen? It would not have been just a few generations.

Answer 4

Most of earth covered with water - primitive life eventually evolves into fish. Then, with the environment of swampy wetlands, some fish evolve into land animals (and then the various environments on land produce various land animals). Whales represent coming back full-circle: land animals going to the ocean. Whales and hippos share a common land ancestor (whales still have remnants of legs inside of them).

Answer 5

Mammals evolved from a group of reptiles called therapsids. The earliest true mammals, appearing over 200 million years ago, were only 5 cm (2 in) long and probably spent at least some of their lives in trees. These tiny mammals resembled shrews with four roughly equal short legs and sharp claws. Since that time mammals have evolved an extraordinary variety of body shapes and sizes. Of the approximately 4600 species of mammals alive today, most live on land, and most still move about on all four legs. But modern mammals also include animals that hop on two legs, ones that live permanently in water, and ones that can fly. These swimming and flying species include the world's largest mammal—the blue whale, which can grow over 30 m (100 ft) long—and also the smallest, the Kitti's hog-nosed bat. Discovered in 1973 in the forests of Thailand, this tiny bat is about the size of a bumblebee, and weighs just 2 g (0.07 oz).

Whales resemble fish in many ways, but they are not fish. Fish are cold-blooded and breathe underwater using gills; whales, on the other hand, maintain a warm and constant body temperature of about 37°C (about 99°F) and breathe air with lungs. Unlike fish, which move their vertical tail fins from side to side when they swim, whales move their horizontal tail fins up and down to propel themselves through the water.

Whales belong to the mammalian order Cetacea. Scientists classify whales into two groups. One group, known as the Odontoceti, or toothed whales, have jaws lined with pointed teeth that they use in hunting fish, squid, and other prey. Toothed whales also include dolphins and porpoises. The other whale group, called the Mysticeti, or baleen whales, lack teeth. These whales use giant, flexible combs of a material called baleen to filter small fish and tiny crustaceans from the water.

Whales are found in all the world's oceans and even in a few rivers. One species of dolphin, the pink river dolphin, lives only in the Amazon River and its larger tributaries. Some whales, including the blue, fin, humpback, and gray, undertake some of the longest migrations in the animal kingdom, traveling between the tropics in winter and subpolar waters in summer. Other whales do not migrate long distances or, like the killer whales, wander without specific migratory routes.

Answer 6

Some fish produce live offspring and some mammals like the platypus lay eggs.

Answer 7

If a fish was born breach, could you imagine those scales ripping the cervix on the way out?

Answer 8

Whales used to be wolf like creatures...

Learn before you speak!

A Wiccan and Proud
-Why

Answer 9

Ummmm....because evolution works in mysterious ways =)

or...

Read your science textbook!!

Answer 10

evolution works in mysterious (natural selection) ways