1. INTRODUCTION TO BIOLOGY

2. How does life begin? There were 2 theories: There were 2 theories: –Spontaneous generation –Biogenesis

3. Spontaneous Generation Process by which life begins when ethers enter nonliving things Process by which life begins when ethers enter nonliving things Francesco Redi conducted an experiment to disprove this theory Francesco Redi conducted an experiment to disprove this theory

4. Redi’s Experiment During Redi’s time maggots were thought to come from rotting meat During Redi’s time maggots were thought to come from rotting meat Redi placed meat in an open jar and maggots appeared on the meat Redi placed meat in an open jar and maggots appeared on the meat Redi placed meat in a closed jar and no maggots appeared Redi placed meat in a closed jar and no maggots appeared Critics of Redi suggested that the ethers could not enter the container which is why the maggots did not appear Critics of Redi suggested that the ethers could not enter the container which is why the maggots did not appear

5. Redi’s Revised Experiment Redi placed meat in a jar covered with a mesh cloth to allow ethers to enter but nothing else Redi placed meat in a jar covered with a mesh cloth to allow ethers to enter but nothing else Maggots did not appear on the meat Maggots did not appear on the meat

6. Biogenesis Principle that life comes only from life Principle that life comes only from life After Francesco Redi disproved the theory of spontaneous generation, Louis Pasteur conducted an experiment to prove biogenesis After Francesco Redi disproved the theory of spontaneous generation, Louis Pasteur conducted an experiment to prove biogenesis

7. Pasteur’s Experiment Broth is placed in a flask with a curved neck to prevent dust from entering the broth Broth is placed in a flask with a curved neck to prevent dust from entering the broth The broth is heated and after one year, the broth was still free of bacteria The broth is heated and after one year, the broth was still free of bacteria The curved neck is broken off so that dust can now enter the flask The curved neck is broken off so that dust can now enter the flask After one day, the broth was cloudy and filled with bacteria After one day, the broth was cloudy and filled with bacteria

8. Characteristics of Life Organization: living things are organized; the basic unit of organization is the cell Organization: living things are organized; the basic unit of organization is the cell Energy: living things use sound, light and chemical energy; all living things take in energy from the environment and use it for their life processes Energy: living things use sound, light and chemical energy; all living things take in energy from the environment and use it for their life processes Growth and Development: Growth and Development: –Growth is an increase in size –Development is a change in shape or form

9. Characteristics of Life (cont.) Reproduction: process by which new living things are formed Reproduction: process by which new living things are formed Response and Adaptation: Response and Adaptation: –Response includes migration, movement, color changes, etc. –Adaptation is a way for an entire population of organisms to respond to long-term changes in their surroundings; these are passed on from generation to generation

10. Levels of Organization AtomMoleculeCellTissueOrgan Organ System OrganismPopulationCommunityEcosystemBiosphere

11. Population, Community, Ecosystem & Biosphere Population: group of organisms of the same species that live together in a particular location Population: group of organisms of the same species that live together in a particular location Community: include all organism populations in a particular location Community: include all organism populations in a particular location Ecosystem: all the communities and the non-living parts in a particular location Ecosystem: all the communities and the non-living parts in a particular location Biosphere: thin layer of air, land and water on the surface of the earth Biosphere: thin layer of air, land and water on the surface of the earth