Title: Chapter 14 Diagram BookletDraw, label, and color:

• Fig. 14.2 p. 372

• Fig. 14.3 p. 373

• Fig. 14.9 p. 379

• Fig. 14.11 p. 381

• Fig. 14.12 p. 382

• Fig. 14.15 p. 385

Origins: The Early Ideas

• Spontaneous Generation: the idea that nonliving material can produce life.

Disproving Spontaneous Generation

• Francesco Redi: completed an experiment that disproved spontaneous generation in large organisms

• Louis Pasteur: completed an experiment that disproved spontaneous generation in microorganisms

Redi’s Experiment

• He placed raw meat in jars. • He left some jars uncovered and

he covered some jars with cloth.• Flies could not get to the meat

in covered jars• Only the jars left uncovered

grew maggots• Proving the maggots did not

grow from meat.

Redi’s Experiment

Maggots

No Maggots

Pasteur’s Experiment

• Set up an experiment in which air could reach the broth, but not microorganisms

• Nothing grew in the broth• He tipped the jar allow

microorganisms to enter, and they grew in the broth.

Pasteur’s Experiment

Nothing Grew

Something Grew

Origins: The Modern Ideas

• Biogenesis: the idea that living organisms come only from other living organisms

• No one has yet proven scientifically how life on Earth began.

• However, there are many theories about the beginning of life.

Simple Organic Molecules

• For life to have begun:1. Simple organic molecules

with carbon must have formed

2. Molecules organized into complex organic molecules, such as proteins and nucleic acids

Important Scientists

• Alexander Oparin: Hypothesized that life began in the oceans

• Miller & Urey: tested Oparin’s hypothesis, were able to make simple organic molecules.

Formation of Protocells

• Protocell: a large, ordered structure, enclosed by a membrane that carriers out some life functions.

• Sidney Fox: completed an experiment in which he made protocells

The first true cells

• Anaerobic, heterotrophic prokaryotes: did not use oxygen, did not make food, no membrane bound organelles

• Once the food supply was diminished, autotrophs evolved.

• Archaebacteria: first autotrophs, live in harsh environments

• Photosynthesizing prokaryotes then evolved and supplied the atmosphere with oxygen.

• Also lead to the ozone layer being made.

• Allowing more complex eukaryotes to evolve

Endosymbiont Theory

• Proposed by Lynn Margulis• States that eukaryotic cells

evolved from a symbiotic relationship between two prokaryotes

Evidence for Theory

1. Cyanobacteria resemble chloroplast found in eukaryotic cells

2. Chloroplast and Mitochondria have their own DNA

3. Chloroplast and Mitochondria have their own ribosomes

Endosymbiont Theory