A LEVEL ENVIRONMENTAL SCIENCE: Conditions for Life on Earth
Terms in this set (20)
age of earth
earth is approximately 4.5 billion years old, yet life has only existed on it for 3.9 billion years.
the first recorded fossils are 600 million years old.
- the first organisms that started to develop.
- were single-celled organisms.
- can survive in extreme conditions e.g. extreme heat or cold.
role of extremophiles
helped to improve the conditions of the earth by photosynthesis as oxygen is a by-product.
where the earth is situated in the solar system; not too hot or too cold.
importance of earth's magnetic field
- spinning of earth's core maintains field.
- shield protects atmosphere from being blown away by solar winds.
- without an atmosphere, our oceans would boil away.
conditions for life on earth; availability of water
- essential for organisms to carry out physiological processes.
- important for environment.
- physiological solvent.
- temperature control.
- high specific heat capacity.
- provision of aquatic habitats.
conditions for life on earth; the atmosphere
- greenhouse effect traps heat in lower atmosphere. controls temperature so that it permits life.
- temperature also ensures that gases such as O2 and CO2 remain in a gaseous state.
5 branches of life
- marine organism living in darkness at the bottom of the ocean.
- dated to 560 million years ago.
- 600,000 million years ago.
- ice 1km thick.
- destroyed all living organisms and evolution except for extremophiles.
- melting lead to huge development in life on earth.
- an extremophile that produces O2 and removes CO2.
- algae is a form of cyanobacteria.
- clump of cells.
- one of most primitive organisms.
- cells are held together by collagen, which needs oxygen to form.
earth's environment developed independently of life and living organisms and evolved to take advantage of it.
theory proposes that living organisms and their environment evolved as a single system. biota have made earth fit for life.
concentrations of atmospheric gases WITHOUT life on earth
CO2 = 98%
nitrogen = 1.9%
O2 = 0%
argon = 0.1%
methane = 0%
involves the interaction of life with the lithosphere, atmosphere, and hydrosphere.
a community of plants and animals in the environment in which they live.
a global ecosystem characterised by climatic factors giving rise to similar environmental conditions, e.g. tropical rainforests.
- damaged by frost.
- large leaves.
- live through most conditions.
- sharp needles.