Bio Quiz 2 Flashcards Preview

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Flashcards in Bio Quiz 2 Deck (45)
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1
Q

What is a fossil?

A

Any evidence of a once-living organism.

2
Q

Give some examples of things that are considered fossils.

A

casts, molds, footprints, track ways and feeding traces.

3
Q

Ordinarily, which parts of the organisms are preserved?

A

The hard parts (shells, bones, teeth)

4
Q

What is one of the keys of preservation?

A

The absence of oxygen and the presence of water.

5
Q

Can you date dirt?

A

No

6
Q

Can you date volcanic ash?

A

Yes, using potassium/argon

7
Q

Can you date fossils?

A

Seldom

8
Q

What is unaltered remain?

A

RARE fossils with little or no change in structure and composition.

9
Q

Why are unaltered remains rare?

A

Because the conditions to form seldom occur.

10
Q

What are the 3 types of unaltered remains?

A

Encrustations, amber entombment, refrigeration

11
Q

What are the 2 versions of body fossils?

A

Unaltered, altered.

12
Q

What are encrustations?

A

When dissolved minerals in water form a thin crust on whatever it lies on.

13
Q

What do you get when you dissolve away the encrustation?

A

Original material (usually bones/shells)

14
Q

What can encrustations tell us?

A

How organisms grew when alive.

15
Q

What is amber entombment?

A

When insects are trapped in resin, which hardens into amber.

16
Q

What do you get from amber entombment?

A

Original cellular material, at least partial DNA.

17
Q

When would you be able to get blood or DNA from a dinosaur in an amber entombment?

A

If the insect had bitten a dinosaur.

18
Q

What is refrigeration?

A

When animals are trapped in ice from the ice age.

19
Q

What can we retrieve from refrigeration?

A

Lots of cellular materials, at least partial DNA samples.

20
Q

What are altered remains?

A

Sediments compressed by overlying sediments and undergo lithification.

21
Q

What is lithification?

A

The process of turning to stone

22
Q

What are the 4 types of altered remains?

A

permineralization, replacement, recrystallization, carbonization

23
Q

What is permineralization?

A

When the pores in bones/shells/plantstems are filled with mineral deposits.

24
Q

What can you see from permineralization?

A

The general structure (especially bones and hand tissue), no original material, no DNA, bad detail.

25
Q

What is replacement?

A

When acidic groundwater dissolves a hard structure in an organism that is trapped in sediments. A mineral is deposited in its place.

26
Q

What can we find from replacement?

A

Lots of detail (even their last meal, feathers).

27
Q

What is recrystallization?

A

The conversion of the fossil to new mineral (coarser crystals of the original material).

28
Q

What can we get from recrystallization?

A

No DNA, bad detail.

29
Q

Where do the crystals often form?

A

Inside shells and hollow bones.

30
Q

What is carbonization?

A

When the liquid/gaseous components are forced out leaving only a film of carbon.

31
Q

When does carbonization occur?

A

When the volatile is under pressure.

32
Q

What can we get from carbonization?

A

No cell fragments, outside surface details..

33
Q

What organisms are these fossils usually of? (carbonization)

A

Plants

34
Q

What are the 3 types of trace fossils?

A

Animal tracks, gastroliths, coprolites.

35
Q

What can animal tracks show?

A

The stride, how the animal moves, speed.

36
Q

What can gastroliths show?

A

The type of plant matter eaten.

37
Q

What are gastroliths?

A

smooth, polished stones that helped herbivore dinosaurs break down vegetable matter in their stomachs.

38
Q

What part of the gastrolith shows the type of plant matter eaten?

A

The surface scratches.

39
Q

What are coprolites?

A

Fossilized excrement.

40
Q

What can you find in carnivore coprolites?

A

Bones of its prey.

41
Q

What can you find in herbivore coprolites?

A

Seed and plant fibres.

42
Q

Older things are buried…

A

Deeper.

43
Q

Why are older things buried deeper?

A

Sediments are deposited over time by erosion.

44
Q

What are radio isotopes?

A

Atoms that decay with a set halflife.

45
Q

What is a halflife?

A

The time required for 1/2 of the parental isotope to decay to a daughter isotope.