Biology

• Charles Robert Darwin introduced the Theory of Natural Selection
• Jean-Baptiste Lamarck introduced "Theory of acquired characters"
• Lamarckism includes:-

  1. Use and Disuse of Organs
  2. Effect of Environment
  3. Acquired Characters
• The gradual change that occurs in a living being according to their needs, and environment is known as Evolution.
• There is Organic Evolution and Inorganic evolution.
• Organs:

  • Analogous Organs
  • Homologous Organs
  • Vestigial Oragans
• Homologous Organs: Organs having similar function but different structures
• Analogous Organs: Organs that have similar structure/origin but similar functions
• Vestigial Organs: Organs that are no longer functional but are still present in the body in a reduced size
• Morphology: the study of the external forms of things.
• Anatomy: The study of the internal structure of the body and its parts.
• Paleontology: Study of fossils
• Fossils are considered the strongest evidence of evolution because they show that organisms have changed over time, and you can easily know how old a fossil is, by determining the age of the sedimentary rocks
• Fossils are only found in Sedimentary rocks
• Embryology: the study of the development of an organism from fertilization to birth (embryo)
• Embryology suggests that many common vertebrae evolved from the same common ancestor as they looked similar in their early stage of embryo.
• Hugo De Vries introduced the Mutation Theory
• Mutation: A change in the DNA sequence of an organism that can lead to a change in the phenotype