<< Chapter < Page Chapter >> Page >

3.The modern coelacanth-finding throws doubt on an assumption palaeontologists use when reasoning about what the fossil record says about extinctions.

  • What is the assumption the modern coelacanth-finding throws doubt on?
  • How does the modern coelacanth-finding throw doubt on this assumption?

4.Look at these premises:

  • A cadborosaurus was found in the stomach of a whale in 1993 .
  • A pterodactyl was killed at Culment, France, in 1856 .
  • Blood vessels, red blood cells, osteocytes and proteins have been found in unfossilized dinosaur bones .
  • Undamaged DNA pieces have been found in insects fossilised in amber (a sticky plant resin).
  • Unfossilised bones, blood vessels, blood cells and DNA break down quickly .
  • The extinction of the dinosaurs is assumed at more than 60 million years ago.

Give a conclusion which follows from these premises

5.A rock is found to have a K:Ar ratio of 1:10. Its age is calculated as 4,37 x109 years.

  1. K (potassium) is the parent element. Ar (argon) is the _________________ element.
  2. What data is used to do this calculation?
  3. What conclusion/inference is made from this data?
  4. Name two assumptions used when making this conclusion from this data:
  5. Give a counterargument, showing how this same data could fit with a young age.

Activity: Fossils: Suggested Answers

1.Name / give the term for:

  1. Turning to stone Petrifaction
  2. A fossil in which the surroundings became stone, leaving a cavity where the body had been Mould
  3. The time period and era, according to the geological column, when dinosaurs first appeared Triassic period; Mesozoic era
  4. The time period and era, according to the geological column, when dinosaurs became extinct Cretaceous period; Mesozoic era
  5. A person who studies fossils Palaeontologist
  6. A person who studies rocks Geologist
  7. Layers of deposited material Sediments / Strata
  8. No members of that organism exist anymore Extinct
  9. The time era, according to the geological column, when mankind evolved Cenozoic

2.For each of the following sentences, say whether the information is: (Circle i / ii / iii)

  1. Accepted by definition if people have defined this to be so, or
  2. Known by observation if people have observed this to be so, or
  3. Deduced if people have come to this knowledge by reasoning.
  1. During petrifaction, minerals enter, harden, and turn a body to stone.[ i / ii / iii]Observed and Defined
  2. The Triassic Period is more recent than the Permian Period. [ i / ii / iii]
  3. Defined
  4. The oldest fossils are 650 million years old. [ i / ii / iii]Deduced
  5. A film fossil is a carbon mark left on rock e.g. by leaves. [ i / ii / iii]Defined
  6. The deepest rocks with reptile fossils are classed as Carboniforous. [ i / ii / iii]Defined
  7. Reptiles first evolved 350 million years ago, at the start of the Carboniforous period. [ i / ii / iii]Deduced
  8. Only 2/3 of all types of organisms which have ever lived have left any fossils.
    1. [ i / ii / iii]Deduced

3.The modern coelacanth-finding throws doubt on an assumption palaeontologists use when reasoning about what the fossil record says about extinctions.

  1. What is the assumption the modern coelacanth-finding throws doubt on? An extinction event can be recognised by fossils of that type not being found in higher (i.e. younger) rock.
  2. How does the modern coelacanth-finding throw doubt on this assumption? Although no coelacanth fossils are found in rock younger than that assumed to be 100 million years old, coelacanths are not extinct: they are alive today(extant).

4.Look at these premises:

  • A cadborosaurus was found in the stomach of a whale in 1993.
  • A pterodactyl was killed at Culment, France, in 1856.
  • Blood vessels, red blood cells, osteocytes and proteins have been found in unfossilized dinosaur bones.
  • Undamaged DNA pieces have been found in insects fossilised in amber (a sticky plant resin).
  • Unfossilised bones, blood vessels, blood cells and DNA are known to break down quickly.
  • The extinction of the dinosaurs is assumed at more than 60 million years ago.

Give a conclusion which follows from these premises: Either the assumption that dinosaurs became extinct 60 million years ago is faulty or cadborosauruses and pterodactyls are not dinosaurs.

5.A rock is found to have a K:Ar ratio of 1:10. Its age is calculated as 4,37 x109 years.
a) K (potassium) is the parent element. Ar (argon) is the daughter element.
b) What data is used to do this calculation? The K:Ar ratio .
c) What conclusion/inference is made from this data? The rock is 4,37 x109 years old .
d) Name two assumptions used when making this conclusion from this data:
All the Ar in the rock came from radioactive decay of the K. This radioactive decay happened at the same rate as it had in the past.
e) Give a counterargument, showing how this same data could fit with a young age.
The rock might have started with a lot of Ar in it. The conditions in the past might have caused K to decay into Ar at a higher rate than today. Further,Argon is known to move easily through rocks, so the Ar might not all have come from radioactivity.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
why and for what was five kingdom of classification of organisms introduced
SUBHIKSHA Reply
give the ans as fast as possible
SUBHIKSHA
Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Siyavula: life sciences grade 10' conversation and receive update notifications?

Ask