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Organisms and populations (BOTANY PART 1)

Ecology:The branch of biology that deals with the study of relationships of living organisms with the abiotic and biotic components of their environment.
Ecosystem ecology:The branch of ecology which deals with the study of ecosystems.
Global ecology:The study of climatic change,biodiversity conservation and ecological sustainability.
Species ecology:The study of an individual organism in relation to its environment.
Community ecology:The study of a group of organisms in relation to their environment.
Population:A group of individuals of a plant or animal species,inhabiting a given area.
Community:An assemblage of the populations of organisms that live under a given area and interact with one another.
Biome:A large regional unit characterized by a major vegetative type and associated fauna found in a specific climatic zone.
Biosphere:All terrestrial biomes and aquatic systems of the earth on the global level.
Habitat:The specific place where an organism lives.
Niche:The habitat together with the functions.
Euryhaline:Organisms which can tolerate wide ranges in salinity.
Stenohaline:Organisms which can live within a narrow ranges of salinity.
Auroral:Animals which are active at dawn only.
Vesporal:Animals which are active at dusk only.
Edaphic factors:The factors which relate to the structure and composition of the soil.
Conformers:The organisms which cannot maintain a constant internal environment.
Ephemerals:Plants which complete their life cycle within a short period.
Succulents:Xerophytes which have the capacity to absorb and store water.
Acclimatization:The gradual physiological adjustment to slowly changing new environment conditions.


Human genome project was a mega project which was a project which lasted for almost 13 years coordinated by the US Department of Energy and the National Institute of Health.
The goals of the Human Genome Project are map all the 50,000 to100,000 human genes . construct a physical map of the entire human genome, determine the nucleotide sequences of all 24 human chromosomes.
James Watson was the first director of this project which was expected to take two decades to complete and to cost in excess of $3 billion.Then an international organization can Human Genome Organisation (HUGO) was organized to coordinate the efforts of human geneticists around the world.

Radioactive dating(Uranium)

Uranium is a radioactive element so it decays into an isotope of another element at a fixed rate. Uranium 238 is an isotope of uranium and it has a half life time of about 4.5 billion years.In the case of Uranium ,it finally forms lead 206.Scientists know the rate of transformation of uranium 238 to lead 206,they can determine the age of the rock containing lead 206.
Scientists calculate radioactive dating of rocks by taking the ratio of uranium 238 to lead 206.

Image courtesy: Wikispaces

Principles of inheritance and variation (NOTES PART 1)

Genetics: Study of heredity and variation.

Heredity: Inheritance of characters transmitted from parents to offsprings.

Variation: Degree by which progeny differ from their parents.

Father of genetics- Gregor Johann Mendel.
He conducted experiments in garden pea(Pisum sativam)

Reasons for selecting garden pea,
1.Bisexual flower.
2.Self and cross pollination takes place.
3.Contrasting pairs of characters.
4.Short life span.

There is a particular gene for a particular character.
For indicating a gene ,there are two alleles.


1.True breeding
(Producing same character from same plants by producing them for 3-4 generation,made them pure for that specific character)
By self pollination,he created two pure breeding Tall and a pure breeding dwarf.
A character has two forms a dominant and a recessive form.
For example Height has two forms one is Tall and the other is dwarf.
2.A pure breeding Tall is crossed with a pure breeding dwarf.
At the time of gamete formation,the two factors separate or segregate.
The next generation is known as F1 generation or first filial generation.
In F1 generation, Dominant character T is expressed.
And T is completely dominant over t -- complete dominance.
Thus it expresses tallness.
This observable character is called phenotype.The genetic constitution is called genotype.

3.Then the F1 generation is self polinated.
At gamete formation,both alleles segregate,
TT Tt Tt tt are formed
Phenotype - 3 tall and 1 short is formed.

Genotype - 3genotype TT Tt tt

Phenotypic ratio-3:1
Genotypic ratio-1:2:1
Monohybrid cross-The character of one is crossed.

Reginald C Punnett brought a square called Punnett square or check board for easily finding the phenotype and genotype.