How can you know the date when the living things existed on earth?

Answer 1

Fossils form in rocks when bones are buried by sediment (sand, soil, etc), and that become compressed by layers above until it turns into stone. Therefor, as sediment becomes rock, it forms in layers. All of a particular layer, thus, formed at the same time. So if dinosaur bones are found in a layer, and other animals and plants are also found in the same layer, then they all lived at the same time.

Answer 2

Well some scientists can tell based on stories that were passed down from generation to generation, cave paintings, fossilized items, some preserved items (clothes, baskets, tepees, pots and pans, etc.) , records kept from that civilization (hieroglyphs, statues, paintings, pictures, etc.). There are more ways but at the moment I cannot think of any.

Answer 3

What can be inferred from fossils is a picture of the world way back then. When? Throughout geological history. A colourful picture of past ecosystems come to light from fossils. We know that the Cretaceous was plodded over by tyrannosaurs and ceratopsians for example. By examining the teeth of the tyrannosaurs, we can guess reasonably that they were carnivorous. There were plenty of herbivores around for them to feed on. We can see that tyrannosaurs ate meat by their teeth, but what about the stunted arms? The tiny arms of Tyrannosaurus have been used to suggest that it ate carrion as the arms would have been useless in a hunt and a kill. Perhaps, I hypothesise now that I think of it, the tyrannosaurs were active hunters, but the legs were strong enough to bring a prey animal down (with help from the bite of the long-toothed jaws) and thus the arms (generation by generation, evolution gradual) began to diminish. The diminishing of the arms by Natural Selection was feasible as they were of no particular use in hunting. The arms could get smaller without getting in the way of hunting in the sense of making the bearer less good at hunting.

See, by looking at the anatomy (preserved as fossil bone) of ancient animals, we can see a tiny splinter of their lives and their ecosystem. And even hypothesise how Natural Selection may have brought about their anatomy.

Ceratopsians (like Triceratops) had great frills. We can admire these and infer from them that they might have been used for defence against dangerous meat-eaters. Or, another hypothesis, the frills were coloured and used as bright displays against rivals (see Walking with Dinosaurs).

Plants fossilise too. We know of equisetophyte forests of the Carboniferous and the beginnings of angiosperms in the Cretaceous. There have been many many hypotheses as to the origins of angiosperms and these must take into account the anatomical structures of the flowers. The transitional organismal forms between gymnosperm and angiosperm can be identified by examining the anatomy of such plants, their cones or flowers.

All of today's extant phyla of plants have their fossil representatives. It is the order of the appearance of these fossils that tell us how anatomy shapes evolution, how anatomy leads to success. In plants, we can trace (in fossil form and by looking at extant representatives) the path from bryophyte to vascular plant to gymnosperm to angiosperm.

Answer 4

By their frozen or fossilized remains we can determine their size, diet, habitat and range of movement or migratory habits.

Answer 5

Well fossils don't say but archeologist's say

Answer 6

By radio carbon dating one can find out the age of a fossil, may be with this principle one can predict the age of living things existed on earth but cant predict the exact time.

Answer 7

Through their fossil remains.

Answer 8

Carbon dating