foss-, fossili-, fossil-, fossor- +
(Latin: to dig, digging; dug out, dug up from beneath the surface; ditch, trench)
2. A little hollow; hence, a dimple. 3. A small, deep-centered ulcer of the transparent cornea.
The word fossil comes from Latin follilium, which means "dug up from beneath the surface or the ground"; for example, a mole is spoken of as having a fossorial way of life.
As originally used by medieval writers, a fossil was any stone, ore, mineral, or gem that came from an underground source.
Some of the earliest books on mineralogy are called books of fossils. This broad meaning gradually was restricted in the 18th century to objects in rocks that are parts of once living organisms; such as, bones, shells, leaves, wood, etc.
For many years, there was heated debate about the reality of fossils. Some believed that all fossils resulted from a single Noachian flood (relating to Noah or his time) as presented in Genesis (first book of the Bible).
Others thought that fossils grew in place in the rock or had been placed there by Satan to betray humans. Fossils were found that clearly had been parts of plants or animals that were no longer living on earth.
This raised a debate concerning the perfection of organic creation if some species had become extinct. Gradually fossils became generally accepted as records of ancient life.
Fossils demonstrate two truths about the planet on which we live.
- First, many species have existed and later became extinct.
- Second, there has been a succession of plants and animals through time so that the communities of life that have existed on earth have gradually changed through time both on land and in the oceans.
The main systems are the Steam (Rankine) Cycle and the Gas Turbine (Brayton Cycle).
- Steam (Rankine) Cycle is an ideal thermodynamic cycle that consists of four processes:
- Heat transfer to the system at constant pressure.
- An expansion at constant entropy.
- A constant-pressure heat transfer from the system.
- A compression at constant entropy; used as a standard of efficiency.
- Gas Turbine (Brayton) Cycle, an ideal gas cycle used as a standard for the actual performance of a simple gas turbine, consisting of four processes:
- A reversible adiabatic (no heat transfer) compression at constant entropy.
- A heat transfer at constant pressure up to the maximum temperature.
- An adiabatic expansion at constant entropy back to the original pressure.
- A heat transfer at constant pressure back to the original volume and entropy.
- Entropy in thermodynamics is a measure of the disorder or randomness of a closed system; more entropy means less energy is available for doing work.
The total entropy of an isolated system cannot decrease when the system undergoes a change; it can remain constant for reversible processes, and will increase for irreversible ones.
Oil, natural gas, and coal are examples of fossil fuels.
2. Bearing or containing fossils; such as, rocks or strata.
The totality of fossils and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record.
2. The process of being turned to stone.
3. Becoming inflexible or out of date.
Fossilization is considered a rare occurrence because most components of formerly-living things tend to decompose relatively quickly following death.
In order for an organism to be fossilized, the remains normally need to be covered by sediment as soon as possible; however, there are exceptions as to when an organism becomes frozen, desiccated, or comes to rest in an anoxic (oxygen-free) environment; such as, at the bottom of a lake.
2. To replace organic with mineral substances in the remains of an organism.
3. To make outmoded or inflexible with time; an antiquate.
4. To change as if into mere lifeless remains or traces of the past.
They excavate cells in the earth, where they deposit their eggs, with the bodies of other insects to serve as food of their young after they hatch.
2. A reference to the parts of an animal body used for this purpose.
3. Adapted for or used in burrowing or digging; such as, the fossorial forefeet of a mole.