How historical conditions for life were monitored in the past and how these methods have been developed over time

Question 1

Proxy data is…

Answer 1

Data which is collected on other things and used to estimate climate.

Question 2

Oxygen Isotope Ratio

Answer 2

Example of proxy data. There are 2 types of oxygen isotopes (o-16 and o-18) and both of these are stable so they do not go through radioactive decay. The shells of ocean creatures take in this oxygen as they grow (this is then retained in their fossilized shell). At the oceans surface, lighter isotopes evaporate more easily, so levels of o-16 are more effected.

Question 3

What does oxygen isotope ratio tell us?

Answer 3

Give us an idea of the average temperature of a past climate.
If it is warmer, o-16 levels will be similar to o-18, because o-16 will evaporate, condense, fall back as rain into ocean.
If it is colder, o-18 will be higher, because
o-16 will condense into snow and won’t end up back into the ocean.

Question 4

But how do we know how long ago this organism died?

Answer 4

We use Carbon Dating. Living organisms absorb carbon-14, but when they die, this slowly decays into other atoms at a predictable rate. This means that, by measuring how much carbon-14 remains, we can estimate how long a particular object has been dead.
THEN WE CAN USE THIS INFO TO PLACE IT INTO A SPECIFIC TIME AND USE ORGANISM TO PREDICT THE CLIMATE THEN.

Question 5

Air bubbles in ice cores

Answer 5

Ice cores are cylinders of ice which are drilled from ice sheets and glaciers, etc. These have trapped air bubbles within them, which give direct samples of past atmospheres so the composition of the atmosphere can be predicted.

Question 6

Limitations of early methods.

Answer 6

Lack of ancient historical data.
Limited reliability of proxy data for ancient conditions.
Limited coordination between researchers.
Lack of sophisticated equipment for accurate measurements.
Inability to measure many factors.
Lack of data collection in many areas.
Reliance on proxy data, eg dendrochronology, pollen analysis.

Question 7

Improved methods.

Answer 7

Collection of long-term data sets.
The use of electronic monitoring equipment.
Gas analysis of ice cores.
Isotope analysis of ice cores.
Improved carriers for monitoring equipment, eg helium balloons, aircraft, satellites.