Points To Remember -Class 10 -Science-Biology-Chapter 8 :Heredity and Evolution

Class 10 -Science- Points To Remember -Biology-Chapter 8 :Heredity and Evolution

Introduction:

•         Heredity involves the transmission of traits from one generation to the next, while evolution describes the gradual development of complex organisms over multiple generations.

Heredity:

•         Genes, functional units of heredity, pass on characteristics from parents to offspring through DNA.

•         Genetics, a branch of biology, studies genes, heredity, and variations.

Sexual Reproduction:

•         Involves the fusion of gametes from two individuals to create offspring.

Genes:

•         Functional units of heredity, each controlling specific characteristics in organisms.

Mendel’s Work:

•         Gregor Mendel’s experiments with pea plants laid the foundation for modern genetics.

•         Established three laws of inheritance: Dominance, Segregation, and Independent Assortment.

Inheritance:

•         Transfer of traits from one generation to another, governed by Mendel’s laws.

Sex Determination:

•         Determining an individual’s sex based on genetic composition, such as XX for females and XY for males.

Traits:

•         Characteristics of an organism, either acquired or inherited.

•         Acquired traits result from environmental influences, while inherited traits are passed down genetically.

Variation:

•         Differences among individuals of the same species, caused by recombination and mutation.

•         Genetic variations result from diverse DNA sequences.

Natural Selection:

•         Process by which advantageous traits are favored in a population due to environmental pressures.

Speciation:

•         Formation of new species from existing ones, driven by evolutionary forces like genetic drift, isolation, and natural selection.

Gene Flow:

•         Transfer of genes between populations through migration, affecting gene frequencies.

Evolution:

•         Tangible change in heritable characteristics of a population over generations, leading to species diversity.

Fossils:

•         Preserved remains of ancient organisms, providing evidence for evolution and species development.

Evolutionary Relationships:

•         Deduced through the study of homologous and analogous structures in organisms.

Evolution by Stage:

•         Gradual process where complexities evolve bit by bit over time.

Artificial Selection:

•         Human-driven process leading to the evolution of different species from a single ancestor, demonstrated in the cabbage family.

Molecular Phylogeny:

•         Study of evolutionary relationships at the molecular level using DNA sequences.

Human Evolution:

•         Humans belong to the primate family, with close genetic connections to other primates.

•         Ancestors include Dryopithecus, Australopithecus, and various Homo species leading to Homo sapiens.