True or False?
1. A fossil usually contains only the hard parts of an organism.
2. The chemical makeup of an organism does not change when it fossilizes.
3.Most layers fossilizes in older layers of sedimentry rock are more complex in body structure than those fossilized in younger layers.
4.The fossil record does not show every step in the evolution of life forms.
5.Layers of rock can often be dated by the types of fossils they contain.
plz give some expalanations why you choose true or false.
Comments
1. False. While most fossils are regarded as animal bones, a total definition of a fossil would also include leaf imprints. When leaves fall on the ground and are preserved on mud for many years, that is considered a fossil. The leaf deteriorates and what is left is just the imprint. Other examples of "non-hard part" fossils are footprints and fish imprints (some ancient fish had cartillage for their skeleton, much like sharks or did not have bones at all).
2. False. While organisms are alive, they are largely made up of Carbon-14 and exchanges this with the environment (CO2 release or glucose consumption- C6 H12 O6). However, this isotope of Carbon (I dont know how much chem you have learned) breaks down into Nitrogen when it dies because there is no more exchange with the environment.
3. Sort of. From what I understand, you are saying "the older the layers of rock fossils are found, the more complex they are." This isnt 100% true. There have been several extinctions over Earths geological history and many complex organisms have died out. These organisms could be more complex than the organisms that came afterward However, if you compare a fossil that is very old such as a prehistoric fish with a fish that was more recently fossilized (recent meaning a few ten-thousand years ago) then the older fossils would actually be simpler in body structure. Oh and quick note, complex doesnt mean big, more times than often smaller things are complex as well (i.e. flowers and their 4 parts).
4. True. The fossil record is incomplete, but this is because there are many specific steps needed to be taken before something becomes a fossil. (See wikipedia link) Given the rareness of these occurences, the fossil record is amazingly adequate and showing patterns of evolution (i.e. evolution of a short - under a foot tall-, five toed horse to the modern tall, one toed horse.
5. True. Certain organisms are widespread throughout the world and are used as a basis for figuring out how old the surrounding organisms/rock layer is (index fossils). These index fossils are used for something called relative dating where scientists can get a general idea of how old something is by looking at the organisms around it. Say we found a fossil whose age we didnt know, but the organisms around it included a shell from a mollusk that lived between 405 million years ago to 400 million years ago, and a shell from another animal that was alive from 402 million years ago to 390 million years ago. With this knowledge, we could estimate that the fossil found would be between 402 million years old to 400 million years old. This is a very large range, but it still gives a good general idea of age.
Edit: b/c misread 2nd question
1 T because its usually not always
2 T it no longer deteriorates
3 I cannot agree because of certain discoveries around the world.
4 T only the present organism was protected
5 T thats the theory we base evolution on
This was a freeby, next question will cost you. If you dont want to pay then take the time to do your homework as you took the to time all that. Its for your own good.
1. True, the cartilage would have decayed
2. True, it is still carbon
3. Choppy wording, sorry, I can't understand.
4. True, it's "frozen" in rock, ony one stage.
5. False, it's the other way around I think.
I haven't studied this in a while. It may be in your best interest to not take my answers for granted.
1-3 false
4&5 true
Its false
True cuz it cant b false
its all true cuz im learning this in class
true. because the statements are right.
STOP ASKING PEOPLE TO HELP YOU IN YOUR HOMEWORK. CAN'T YOU DO IT YOURSELF????
false!!