DNA is a molecule that encodes all the properties of a species like the color of the eyes or the shape of the body. Like a program containing instructions for a computer, DNA contains instructions for the function of every cell. Its vocabulary only consists of 4 letters − A, C, G, and T − for the 4 elements that compose it: Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). DNA has the shape of a double helix.
Relative to human activity. Any element directly or indirectly caused by human action can be described as anthropogenic (soil erosion, water pollution, etc.). From the Greek anthropos (man).
RNA is very similar to DNA. It consists of 4 elements, one of which is different from DNA: Adenine (A), Cytosine (C), Guanine (G) and Uracile (U). Contrary to DNA, RNA has the shape of single branch helix.
Whereas DNA stores the genetic information of a cell, RNA is involved in the production of proteins and is itself produced by DNA.
The biota, in ecology, is the set of living organisms (animals, plants but also micro-organisms such as bacteria) of a particular region, habitat, or geological period.
- Stem cell
A stem cell is a cell which is not specialised and can therefore perform the functions of a specialised cell.
Stem cells can therefore be used to repair damaged organs. The placenta and the ombilical cord are rich in stem cells.
Bacteria living in regions without light at the bottom of the ocean are able to survive through chemosynthesis. They use energy from the oxidation of inorganic chemicals, such as sulfur released from deep hydrothermal vents, to produce their food.
Cloning consists in identically reproducing a living organism (that can be a cell in a lab). The new organism thus obtained is called a clone.
In biology, this term refers generally to all the processes by which living beings separate geographically from their population of origin and colonise a new territory.
An ecosystem includes all living things (plants, animals and organisms) in a given area. They interact with each other and with their non-living environment (weather, earth, sun, soil, climate, atmosphere). In an ecosystem, each organism has its own niche or role to play.
A gene is a component of DNA which encodes a protein. This is translated into a visible characteristic such as the color of the eyes.
Set of genes of a living organism. Human beings have between 19000 and 20000 genes.
Geophysics is a discipline of Earth Sciences that studies the physical characteristics of Earth (and other planets) such as volcanism, earthquakes, the Earth's magnetic field, etc ... The measurement techniques used are, for example, seismology, satellite mapping, heat flux measurements, petrology of rock samples, gravimetry, geomagnetism ...
From these measurements and field observations, experimental and/or numerical models are developed to try to reproduce and explain these terrestrial features.
Some of these models are used for the prediction of some very dangerous terrestrial phenomena such as earthquakes, volcanic eruptions and landslides.
Genetically Modified Organism. Living organism whose genome has been artificial modified by man. GMO plants like maize are currently cultivated (and commercialised) because they resist better to insects.
Measure and study of gravity.
- Greenhouse gases
These are gases capturing the sun's heat in the atmosphere. For example, carbon dioxide (CO2) and water vapour (H2O).
- Hydrothermal source
A hydrothermal source is like an "exhaust pipe". It is a vent that gases traverse which heats the water around it. There are many of these vents on Earth. If they are on land, they are usually hot springs, geysers or fumaroles (steam coming out of the ground).
Rock originating from a magma, which is emitted in a more or less fluid form (liquid or pasty) by erupting volcanoes
It is molten rock containing dissolved gases and crystals.
- Managed realignment
In the context of coastal erosion, managed realignment, also called managed retreat, consists in altering flood defences to allow flooding of a presently defended area. This is done when the costs of compensation are significantly less than the costs of building coastal defences and can also be beneficial to plants and animals by providing new habitat.
- Fluid dynamics
Study of the physical behaviour of fluids (liquids, gas and plasmas).
In physics, a model, whether experimental (made from experiments) or numerical (made with a program on a computer), is a simplified study of part of a physics phenomenon. Models do not represent the reality but they allow to describe real facts.
Study of rock formation.
The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
In biology, symbiosis is the sustainable and mutually beneficial association between two living organisms.