Fossils - the remains of organisms that lived while the sediments were accumulating

Radioactive isotopes - incorporated into rocks and fossils in proportion to their presence in the environment when the rock solidified. Each decays at its own rate and becomes stable

-used to calculate absolute ages of rocks from the proportions of radioactive and stable isotopes they contain

-earth 4 billions yrs old

-fossils 3.8 billion yrs old

Life arose from nonlife

Life began with interactions among molecules that stored information in easy-to-copy sequences.

-chemical information became more complex when the information stored in these simple sequences resulted in the synthesis of larger molecules with complex but relatively stable shapes. They were complex and stable so they could participate in increasing numbers and kinds of chemical reactions.

• Organic molecules - carbohydrates, lipids, proteins, and nucleic acids (large molecules) are formed by living systems
• found in all living systems
• 3.8 billion yrs ago interacting systems of molecules were enclosed in membranes = CELLS
• control over entrance/exit of molecules, chemical reactions in cell
• effective energy captures and replicators

• 1^st to observe cells (cork, wood, etc…empty)

The first organisms were single cells -

• cells must obtain raw materials and energy from enviro to survive
• metabolism - raw materials - digested chemicals (products used to synthesize large carbon-based molecules)
• a major theme in the evolution of life is the development of increasingly diverse ways of capturing external energy and using it to drive biologically useful reactions.

• sexual recombination - combining of genes from two cells in one cell = variable offspring. Reproduction with variation is a major characteristic of life
• Adaptation to environmental change is one of life's most distinctive features.
• Adapted - able to survive and reproduce
• Sex - exchange of genetic material, reproduction - cell splitting

• Predators - small cells usu destroyed, but sometimes became part of larger cells
• Eukaryotic - complex membrane enclosed internal compartments (organelles)
• Genes and chromosomes - became complex and contained in nucleus
• Prokaryotes - 1 cell membrane

• #1 ability of a cell to change it's structure and functioning to meet the challenges of a changing environment. (spores)
• #2 allowed cells to stick together after they divided, forming a multicellular organism

The cells of an organism are constantly changing

Evolution quickened - multicellular life & changing atmosphere (plants grew)

Homeostasis - maintenance of relatively stable internal condition - (by adjusting metabolism in response to external and internal signals indicating temp, presence/a of sunlight, presence/a of chemicals, need for food & water, presence of a foreign body

• metamorphosis - in response to internal chemical signals, caterpillar changes into a pupa and butterfly
• A major theme in the evolution of life is the development of increasingly complicated systems for responding to signals and maintaining homeostasis.

• A vial characteristic of living organisms is regulated growth (cancer, unregulated growth, destroys life) - cannot achieve adult shapes or function without it

• evolution accompanied by storage of larger and larger quantities of information and increasingly complex mechanisms for using it.
• Species - genetically independent group
• New species may be created if a population is divided and reproduces within group

Biological Diversity: domains and kingdoms -

• 3 domains (Archaea, Bacteria, Eukarya) and six kingdoms -

• Archea (Archaebacteria) Bacteria (Eubacteria)

- Eukarya - eukaryotic cells with nuclei and complex cellular compartments (organelles)

- four kingdoms (protista, plantae, fungi, animalia)

• Kingdom Protista - single-celled organisms. Remaining 3 kindoms (almost all multicellular) - arose from ansestral protists
• Kingdom Plantae (plants) - convert light e^- by photosynthesis.
• biological molecules plants & some protists synthesize are primary food for others
• Kingdom Fungi - molds, mushrooms, yeasts - heterotrophs - require a food source of energy-rich molecules synthesized by other organisms.
• Absorb food substances from their surroundings and digest them within their cells.
• Important decomposers of dead organisms
• Kingom Animalia (animals) - heterotrophs that ingest food source, digest, and absorb products, eat other life

The world Into Which Darwin Led Us -

- Count Leclerc de Buffon - Natural History of Animals (book) - possibility of evolution

• believed species were divinely created for different ways of life, but found arm anatomy to be the same, noticed pigs have toes that never touch the ground and are of no use. Hard to explain if everything was divinely created for a special purpose.
• Suggested limb bones of mammals might have been inherited and pigs have functionless toes b/c they were inherited from ancestors with functional toes descent with modification

• suggested lineages of organisms may change gradually over many generations as offspring inherit structures that have become larger and more highly developed as a result of continued use or have become smaller and less developed with disuse

1. Earth is very old, and organisms have been changing steadily throughout the history of life.
2. All organisms are descendants of a single common ancestor
3. Species multiply by splitting into daughter species; such speciation has resulted in the great diversity of life found on Earth
4. Evolution proceeds via gradual changes in populations, not by the sudden production of individuals of dramatically different types.
5. natural selection = major agent of evolutionary change

Darwin states his case for natural selection -

Natural selection - is the primary agent that adapts organisms to their environments.

Asking the Questions "How?" and "Why?"

• how does it work (deals with molecular mechanisms underlying muscular contraction)
• why has it evolved to work in that way? (deals with why it is adaptive, improves survival)

1. make observations
2. ask questions
3. hypotheses - tentative answers to questions
4. predictions based on hypotheses
5. test predictions bye making additional observations or conducting experiments.

1. colored not attacked by birds
2. hypothesis - colors mean they are distasteful

null hypothesis - exists for each hypothesis - asserts that the proposed effect is absent

3. testing - blue jay ate a monarch caterpillar and vomited

1. emergent of sys = interactions among their parts
2. aggregations have collective properties that individual units lack (i.e. individuals are born and die, but populations have birth and death rates) also age distribution and density