Another example that the present may hold clues to the past . (Catfish hunts on land)

One big question has alweays been why would sea creatures evolve into land animals. A recent Catfish study may offer some insight into what may have happened. {Fixed typo in topic title. - Adminnemooseus}
{Added the "(Catfish hunts on land" part to topic title. - Adminnemooseus}This message has been edited by Adminnemooseus, 04-14-2006 03:41 PMThis message has been edited by Adminnemooseus, 05-02-2006 04:50 PM

What I find is interesting is that comparing ancient fossils with living animals can give us clues on to what could have happened.

Exactly. The process never stops.

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Aslan is not a Tame Lion

So far, in three messages, we seem to have two words of content - "catfish study".Could you have done a worse job in starting this topic?Adminnemooseus

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Jar.The clue to answering to your question is within the article you cited.

quote:

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a new study reveals they slither around and adeptly catch insect meals

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Invertebrates preceded vertebrates on land by millions of years, and plants established on land even earlier.The payoff for a transition to terrestrial existence was the opportunity to feed on terrestrial plants and invertebrates that had escaped natural enemies in marine environments and were likely poorly defended, having never faced browsers or predators subsequent to their own transition on to land. The real payoff for the initial colonizers would have been a new resource base to exploit without any predators in situ.

Invertebrates? Is that like bugs and such? Why is that?

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Aslan is not a Tame Lion

Yes. Anything without a backbone. The kinds of things that make great food for larger things with backbones. Think about it. The first small plants to colonize land would have had a virgin environment to exploit, abesnt the competitors they surely would have faced in their marine environment. Same goes for the first small invertebrates. Assuming they were a little later, they would have found a bunch of plants to eat that had not been investing much in chemical defenses, being unbrowsed since their transition to land. Later still, larger vertebrate animals would have found huge, relatively unexploited, resources of food in the forms of both plants and invertebrates when they first made the transition to land.

In the report it says that the cat fish, because of the way they are built, climb up on land, bonk the bug, then drag it back into the water to eat.So if one slightly different catfish had a mutation that let him eat on land without the step of having to return to the water to eat on each bug bash trip, that cat fish would have an advantage?

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Aslan is not a Tame Lion

Yes, but it goes a lot deeper than simply being able to eat on land. The critical adaptations for terrestrial existence would be as follows.1. Ability to breathe air for indefinite periods (thorough modified gills, presumably).This would enable longer foraging bouts on land.2. Internal fertilization. (A whole host of consequences arise from this one). Without this adaptation, vertebrates would be still tied to the marine environment for reproduction (recall fish and amphibians fertilize externally).3. Eggs able to withstand desiccation in terrestrial habitats.
An alternative to this was adopted by most vertebrates - increased gestation periods with live birth of altricial young, followed later on by live birth of precocial young in some larger vertebrates.