Comprehensive study guide explaining how characters are transferred from parents to offspring and how living organisms change over generations. Heredity ensures continuity of life, while evolution brings diversity among organisms.
Heredity and evolution are fundamental concepts in biology that explain how characters are transferred from parents to offspring and how living organisms change over generations. Heredity ensures continuity of life, while evolution brings diversity among organisms.
Heredity is the transmission of genetic characters from one generation to the next.
Variation refers to differences among individuals of the same species.
Gregor Mendel, known as the "Father of Genetics," studied inheritance using pea plants.
Study of inheritance of one pair of contrasting characters.
Example: Crossing pure tall pea plant with pure dwarf pea plant
Conclusion:
Genotype: The genetic makeup of an organism (e.g., TT, Tt, tt)
Phenotype: The physical appearance or observable characteristics of an organism (e.g., tall, dwarf)
Humans have 23 pairs of chromosomes (46 total).
Key Fact: The sex of the child is determined by the male parent since females contribute only X chromosomes, while males contribute either X or Y chromosomes.
Evolution is the gradual change in organisms over long periods, leading to formation of new species.
Acquired characters: Develop during an organism's lifetime; not inherited (e.g., muscle built through exercise)
Inherited characters: Controlled by genes; passed from parents to offspring (e.g., eye color, blood type)
Speciation is the formation of new and distinct species in the course of evolution.
Speciation occurs due to:
Organisms with common ancestors show similarities in structure, development, and genetic makeup.
Evolutionary Tree: A diagram that shows the evolutionary relationships between different organisms based on their evolution from common ancestors.