Autotroph : It is defined as an organism that can make organic molecules from inorganic nutrients.
Continent Drift : The drift of continents with respect to one another over the plates in the earth’s interior.
Extinction : Disappearence of species from the earth is called extinction, e.g. Dodo became extinct from Mauritius.
Fossil : The remains of ancient organisms (plants and animals) in sediments and rocks are called fossils.
Lineage : A line evolutionary descent from a common ancestor.
Mass Extinction : An episode of large scale extinction in which large number of species disappear in a few million years or less.
Microsphere : Formed from proteinoids exposure to water; has properties similar to today’s cells.
Ocean Ridge : The ridge on the ocean floor where oceanic crust forms and from which it moves laterally in each direction.
Ozone Shield : Formed from oxygen in the upper atmosphere. It protects the earth from ultraviolet radiation of the sun.
Palaeontology : Study of fossils that results in the knowledge of the history of life.
Phyletic Gradualism : An evolutionary model that proposes evolutionary change resulting in a new species which can occur gradually in an unbranched lineage.
Plate Tectionic : The study of the behaviour of the earth’s crust in terms of moving plates is known as plate tectionic.
Proteinold : Abiotically polymerized amino acids that are joined in a preferred manner; possibly an early step in cell evolution.
Protocell : A cell forerunner developed from cell-like microspheres.
Punctuated Equilibrium : An evolutionary model that proposes that there are periods of rapid change dependent on speciation followed by long periods of stasis.
Sedimentation : The process by which particulate material accumulates and forms a stratum.
Abiogenesis : Origin of life from non-living materials.
Aminocentesis : A technique by which the sex, as well as chromosomal and bio-chemical abnormalities in the developing foetus can be diagnosed.
Analogy : Structurally different but functionally alike organs.
Atavism : Reappearance or refunctioning of vestigial organs.
Autoecology : Study in interactions of individuals with their environment.
Chemoheterotrophs : Organisms depending on organic molecules in the broth for getting energy.
Coacervate : Large colloidal cell like aggregates of complex organic compounds.
Connecting Link : A living organism with characters of two different groups and shown path of evolution.
Degradation : Lowering or wear and tear.
Diastrophism : Vertical uplifting of the large tracts of the earth’s crust through a number of geological forces.
Eobiont : Cell-like bodies with division powers.
Evolution : A slow, continuous and irreversible process of change.
Food Chain : A series of trophic levels showing repeated ‘eating and eaten by’ interactions.
Food-web : A net formed by interlinking of many food chains.
Genetic Engineering : Science which involves the manipulation of genetic material by insertion or elimination of DNA into a cell.
Homology : Structurally alike but functionally different organs.
Hydrosphere : Hydro means water, the water in oceans, lakes, rivers and on land forms hydrosphere.
Lithosphere : Solid physical portion of biosphere, i.e. rocky part of the earth.
Nebula : The condensed mass of dust and gas.
Photoautotrophic : Ability of synthesizing the carbohydrates in the presence of sunlight.
Synecology : Study of interactions between different populations of a community of a specific geographical area.
Adaptation : An organism’s modification in structure, function, or behaviour which increases the likelihood of continued existence.
Biogeography : The study of the geographical distribution of organisms.
Catastrophism : The belief exposed by Cuvier that periods of catastrophic extinctions occured after which repopulation of surviving species took place giving the appearance of change through time.
Evolution : The descent of organisms from common ancestors with the development of genetic and phenotypic changes over time that make them more suited to the local environment.
Fitness : The ability of an organism to survive and reproduce in its environment.
Homologous Structure : In evolution, a structre that is similar in different organisms because these organisms are derived from a common ancestor.
Inheritance of Acquired Characteristics : According to Lamarck the organisms become adapted to their environment during their lifetime and pass on these adaptations to their offsprings.
Natural Selection : The guiding force of evolution caused by environmental selection of organisms most fit to reproduce, resulting in adaptation.
Vestigial Structure : The remains of a structure that was functional in some ancestor but now not functional in the organism in question.
Adaptive Radiation : The formation of a large number of species from a common ancestor.
Allopatric Speciation : The origin of new species in populations that are separated geographically.
Directional Selection : An outcome of natural selection in which an extreme phenotype is favoured, usually in a changing environment.
Disruptive Selection : An outcome of natural selection in which extreme phenotypes are favoured over the average phenotype and can lead to more than one distinct form.
Fitness : Fitness is the ability of an organism to survive and reproduce in its environment.
Gene Flow : The sharing of genes between two populations through interbreeding.
Gene Pool : The total of all the genes of all the individuals in a population.
Genetic Drift : A change in the genetic make up of a population due to random events; important in small populations or when only a few individuals mate.
Hardy-Weinberg Law : A law stating that the frequency of an allele in a population remains stable under certain assumptions, such as random mating; therefore, no change or evolution occurs.
Population : A group of organisms of the same species occupying a certain area and sharing a common gene pool.
Postmating isolating Mechanism : An anatomical or phy-siological difference between two species that prevents successful reproduction after mating has taken place.
Premating Isolating Mechanism: An anatomical difference between two species that prevents the possibility of mating.
Speciation : The process whereby a new species originates or is produced.
Species : A taxonomic category whose members can only breed successfully with each other.
Stabilizing Selection: An outcome of natural selection in which extreme phenotypes are eliminated and the average phenotype is conserved.
Sympatric Speciation : The origin of new species in populations that overlap geographically.
Organic Evolution : The process of gradual and orderly change, which has led to the development of present day complex forms of life from pre-existing simple ones, is called organic evolution.
Intraspecific Struggle : This is the struggle between the members of the same species is called intraspecific struggle.
Interspecifc Struggle : This is the struggle between the members of two different species is called interspecific struggle.
Environmental Struggle : The struggle of living organisms against the environmental odds such as extremes of temperature, light and water is called environmental struggle.
Variations : The differences which occur in closely related organisms are called variations.
Morphological Variations : Morphological variations are in size and shape of the body.
Physiological Variations : Variations in body functions, which differ from one individual to another, are called physiological variations.
Behavioural Variations : Variations seen in the behaviour of animals are called behavioural variations.
Differential Reproduction : The tendency of individuals to reproduce at different rates is called differential reproduction.
Archeozoic : The oldest geological era of earth on geological time scale.
Aneuploidy : When one or two chromosomes increase or decrease in the diploid number of chromosomes of an organism.
Anthropology : It is the branch of science which deals with physical, social and cultural development of human beings.
Analogous Organs : Organs which are developmentally dissimilar but functionally similar. They are analogous organs. They represent convergent evolution, e.g. wing of a bird and wing of an insect.
Phylogeny : The ancestral history of an organism or race.
Ontogeny : It is defined as life history of an individual.
Genetic Drift (Wright Effect) : The theory of genetic drift was developed by Sewall Wright in 1930. It refers to the random fluctuations in the gene frequencies in a small population from generation to generation.
Igneous Rock : The rock solidified from lava or molten rock is called magma.
Micro Fossil : A fossil which is microscopic in size.
Palaeo-ecology : The study of ancient ecology.
Missense Mutation : Missense mutation is one that results in the replacement of one amino acid by another.
Nonsense Mutation : A kind of mutation which brings terminating codon, hence the polypeptide chain elongation will stop.
Silence Mutation : A point mutation brings a change in the third base of the triplet code which is not noticed in the transplation. It is called silent mutation.
Sympatric Specification : Origin of new species from population of a single species which has been genetically isolated because of physiological or behavioural incompatibility.
Phenetics : It is taxonomic method. It classifies the organisms based on the number of characters they have in common.
Allopatric Specification : When two related populations live in different areas.
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