Biology Chapter on Spontaneous Generation

Spontaneous Generation

• Spallanzani: boiled broth in open and closed bottles. Microorganisms only appeared in the open bottle, proving they entered from the air, not spontaneously generating.
• Pasteur: Used swan-neck flasks to disprove spontaneous generation. Broth remained sterile despite open air, showing microorganisms only appeared when they could reach the mixture.

Theories of Life's Origin

• Divine Creation: Oldest belief, stating life originated from a divine being.
• Spontaneous Origin: Belief that simple molecules combined into complex ones, with energy sources like lightning, geothermal, electric sparks.
• Panspermia: Life originated outside Earth and transported to Earth through meteorites or cosmic dust.

Cell Structure and Function

• Cells: The basic unit of life, with all organisms composed and developing from cells.
• Unicellular: Single-celled organisms with a single cell often identical to the parent.
• Multicellular: Organisms composed of many cells, undergoing differentiation.
• Cells are Small: Cells are highly organized and contain specialized structures (organelle) that carry out cell processes.
• Cells contain DNA: Cells are surrounded by a plasma membrane and contain DNA, the genetic information.

Stability and Homeostasis

• Organisms must maintain stable internal conditions, known as homeostasis.
• Examples of internal conditions: temperature, water content, chemical content.

Reproduction and Inheritance

• All organisms reproduce and pass on their hereditary information to their offspring through inheritance.
• DNA: Contains instructions for traits, genes that make structures and complex chemicals, and is in every body cell (somatic cells).
• Sexual Reproduction: Combination of hereditary information from two different organisms of the same species.
• Asexual Reproduction: Hereditary information from one organism that divides, resulting in cells with identical information.

Evolution

• Populations of organisms change over generations, leading to different kinds of organisms coming into existence.
• Natural Selection: Organisms with favorable traits successfully reproduce, causing gradual changes in populations.

Interdependence of Organisms

• Organisms interact with each other and their environment, which is called ecology.
• Organisms rely on each other, such as insects and flowers for food and pollination.

Matter, Energy, and Organization

• Living things are highly organized and require energy to maintain their order.
• Energy: All energy originates from the sun.
• Photosynthesis: Organisms capture solar energy and convert it to chemical energy usable by living things.
• Autotrophs: Organisms that produce their own food.
• Heterotrophs: Organisms that must take in food for energy

Characteristics of Life

• Cells: All living things are built from cells.
• Organization: Organized at both the molecular and cellular levels.
• Energy Use: Energy is used in metabolism, the sum of all chemical processes.
• Homeostasis: Stable internal conditions are maintained.
• Growth: Growth occurs through cell division and cell enlargement.
• Development: The process by which an adult organism arises.
• Reproduction: Essential for the continuation of species.
• Responsiveness: React to stimuli in the environment.
• Evolve: Adapt to their environment through adaptations driven by natural selection.

Explore the fascinating theories of life's origin and the experiments that shaped our understanding of biology. This quiz covers key figures like Spallanzani and Pasteur, and concepts such as spontaneous generation and cell structure. Test your knowledge on the foundations of cellular biology.