Biology, 29.06.2019 01:00 zmoore8015

About when did the first limbs evolve in tetrapods (land-dwelling vertebrates)?

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Answer from: do1213

365 million years ago

Explanation:

The tetrapods are a super-family which includes all living and extinct vertebrates that have walked and are still walking the Earth, including the mammals, reptilians, dinosaurs, sinapsids, pterodactyls, amphibians, birds. They have evolved from fish-like creatures that were living in the shallows, and over the course of millions of years they were slowly changing and adapting to amphibian life, thus partially aquatic, partially terrestrial. The first proper limbs, at least what is know so far from the fossil records, have emerged with the ichthyostega and acoantostega around 365 million years ago. These two species were able to lift their body above the ground with their limbs, support its weight, and walk on them without dragging their body on the ground. The first transitional limbs can be seen in a species that has been dated to around 375 million years ago, the Tiktaalik, which had had limbs, but still not well developed, and it was only able to stand on them while in shallow water, but on on land.

Answer from: Quest

Can you be more specific

Answer from: Quest

The scientific method is a series of steps followed by scientific investigators to answer specific questions about the natural world. it involves making observations, formulating a hypothesis, and conducting scientific experiments.the steps of the scientific method are •observation-the first step of the scientific method involves making an observation about something that interests you•question-once you've made your observation, you must formulate a question about what you have observed. •hypothesis-once you've made your observation, you must formulate a question about what you have observed. •experiment-once you've developed a hypothesis, you must design and conduct an experiment that will test it.•results-the results are where you report what happened in the experiment. •conclusion-the final step of the scientific method is developing a conclusion.i hope that this you : )

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