Evolution

Thales- Everything stemmed ultimately from Water. Idea of descent with modification? Aristotle- Everything has a desire to move from lower to higher forms.

How did life develop such a diversity of forms on Earth? The prevailing perception in the Dark and Middle Ages in Europe was that all things on Earth had existed in basically their same forms since they were created.

Pierre Louis Maupertuis-1750 Small Changes between generations could accumulate into large changes given enough time.

Early 1800 ’ s: Mammoths were distinct from Elephants

Fossils

Example: Trilobite From 550 Million Years Ago! Water protects organism for decomposition Bacteria eat soft parts and leave exoskeleton

An organism that is deposited in sediments after death is covered by additional sediments that protect it from predation and decay.

Over time, the weight of additional sediments squeeze out the fluids from the organism and the sediments that surround it, causing lithification (sedimentary rock formation).

Charles Lyell Advocated Uniformitarianism. Believed in an old Earth. The time frame given by an old Earth would allow for Evolution

Evolution

Voyage of the Beagle

Finches

Origin of the Species “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

Tree of Life

Cells

Thermodynamics First Law-The amount of energy in the Universe remains constant Second Law-The Universe tends towards a state of disorder.

Basic Metabolic Needs 1.A source of raw materials with which to build new products. For a cell- key raw materials are molecules that provide the cell with carbon and other basic elements for life

Basic Metabolic Needs 2. A source of energy This fuels the metabolic processes that break down old molecules and manufacture new ones.

Metabolic Classifications Carbon Sources- Heterotroph- ‘ others ’ and ‘ feed ’. Autotrophes- ‘ self ’ and ‘ feed ’ Energy Sources- photo- ‘ from light ’ chemo- from chemicals ’

Photoautotrophs - Chemoautotrophs - Photoheterotrophs – Chemoheterotrophs - Metabolic Classifications

ATP and ADP

Biochemical Processes

Earth Life is Carbon-Based

CARBON- What is the big deal?

Organic Molecules

Silicon-Alternative to Carbon? Although can also bond with 4 atoms at a time- the chemical bonds formed are weaker than those for Carbon

Molecular Components of Cells Carbohydrates- – make important cellular structures –Store energy Lipids- –Can form barriers that make it possible for cells to exist (Cell Membrane!) –Store energy

Proteins Enzymes-serve as catalysts for biochemical reactions.

Evidence for a Common Ancestor Evidence of Single Common Ancestor: 1. All Life uses the Left Handed Version of Amino Acids 2. All Life uses only 20 amino acids 3. All Life uses ATP

Nucleic Acids RNA- Ribonucleic DNA- Deoxyribonucleic

DNA->Genes->Chromosomes

Amino Acids- building Blocks of Proteins

AMINO ACIDS Handedness(Chirality)

Tree of Life

Mutations The Molecular Basis of Evolution 1. Mistake in Replication 2. Exposure to Radiation 3. Exposure to Carcinogens