Unit 13 Notes and Study Links

Unit 13 Evolutionary Theory CONCISE Notes - https://quizlet.com/_1ea5dh

1.      Evolution – gradual changes in organisms over time create new types of organisms

2.      Spontaneous Generation

a.      The idea that life is continually created from nonliving things

b.      Francesco Redi - 1668

                                                              i.      Disproved spontaneous generation of large organisms in 1668 with flies and raw meat

c.       John Needham - 1745

                                                              i.      Heated chicken broth in a flask and proved that spontaneous generation did occur; microorganisms appeared

d.      Lazzaro Spallanzani

                                                              i.      Repeated Needham’s experiment but removed air from flask, microorganisms did not appear

1.      Not convincing because some said air was necessary for spontaneous generation to occur

e.      Louis Pasteur - 1850

                                                              i.      Repeated Needham’s experiment but used a Swan-necked flask, organisms did not appear

1.      kept organisms from reaching the broth

2.      finally disproved spontaneous generation

3.      Biogenesis - The belief that living organisms come only from other living organisms – confirmed by Rudolf Virchow in 1858

4.      Theory of Evolution (Organic Evolution, Biologic Evolution) – the change of populations (species) over time

a.      An explanation of how living organisms came into existence and how they may have changed into more complex organisms.

b.      States that living organisms have changed gradually over time to form new organisms.

5.      Charles Darwin – 1809-1882

a.      Father of Evolution

b.      Book On the Origin of Species

                                                              i.      Studied on the Galapagos Islands (1831) – came on the boat The Beagle

1.      If birds migrated from the mainland to the islands, they should be the same – but they are different – but not completely different – they changed over time to be able to survive the conditions on the island

                                                            ii.      Species – group of organisms that can interbreed and produce fertile offspring

                                                          iii.      Population – organisms of the same species living in the same place at the same time

c.       Four Basic Thoughts – One Very Crazy Saying

                                                              i.      Overproduce offspring – species produce more than can survive

                                                            ii.      Variation – in any population individuals have variations (differences)

                                                          iii.      Competition – (struggle for survival) Individuals compete for a limited amount of resources – food, shelter, protection

                                                           iv.      Survival of the fittest – (natural selection) the individuals that survive pass on their genes, producing generations full of individuals with those helpful genes.

                                                             v.      Descent with modification - All living things have a common ancestor that evolved over time, branched into separate species

d.      The driving force behind evolution

                                                              i.      Natural selection – a process when nature favors organisms that are best adapted to their environment

                                                            ii.      The change is due to a mutation – can be good or bad

e.      Artificial Selection (selective breeding) – when humans purposely breed organisms for specific traits

6.      People that Influenced Darwin

a.      John-Baptiste de Lemarck – 1744-1829

                                                              i.      Had one of the first theories of evolution

                                                            ii.      Believed in spontaneous generation

                                                          iii.      First Law – an organism changed its behavior as its environment changed and acquired tratis

1.      Organism used a body part or organ to adapt to the environmental change, the body part or organ would grow or improve – Acquire the trait. Or if the organism didn’t use a body part or organ, it would shrink or lose function – Law of Disuse - “if you don’t use it you lose it”

                                                           iv.      Second Law – traits are passed to offspring

1.      Organisms would pass on their acquired characteristics to their offspring – heredity

                                                             v.      Ex. Giraffes acquired long necks by stretching them to get food from tall trees (wrong), then passed trait to offspring (right)

Lamarck vs. Darwin

b.      Thomas Malthus – 1776-1834

                                                              i.      struggle for existence and resources leads to survival of the fittest

                                                            ii.      human population growth would lead to poverty and famine

c.       Charles Lyell, a geologist – 1797-1875

                                                              i.      Uniformitarianism

1.      Earth is older than people think and has changed over time due to natural geological events

d.      Alfred Russell Wallace

                                                              i.      Worked with Darwin on natural selection – published a paper together

1.      Did not get any credit after Darwin published On the Origin of Species

7.      Neo-Darwinism

a.      Understanding genetics (DNA, genes, and heredity) has modified original theory of evolution

                                                              i.      Sources of genetic variation

1.      Mutations caused by mistakes in DNA – exposure to radiation, chemicals

2.      Gene shuffling during meiosis – crossing over and independent assortment

8.      Chemical Evolution - The formation of life came from non-living chemicals

a.      Alexander Oparin

                                                              i.      Earth’s early atmosphere contained water vapor, ammonia, hydrogen gas, and methane, but no free oxygen (O₂) because it would have reacted and destroyed the chemicals as they formed

                                                            ii.      Lightning and volcanic heat caused chemicals to combine to form organic molecules

b.      John Haldane – 1928

                                                              i.      energy from the sun could cause these same atmospheric gases to react and form organic (living) compounds

                                                            ii.      organic compounds in the oceans combined gradually over a long period of time into virus-like organisms, when then evolved into the first living cells

c.       Oparin-Haldane Hypothesis – the combined two hypotheses

                                                              i.      Life formed gradually from non-living chemicals over a long period of time

d.      Stanley Miller and Harold Urey  - tested the Oparin-Haldane Hypothesis in 1953

                                                              i.      Miller-Urey Experiment

1.      If the early atmosphere was made up of ammonia, methane, hydrogen, and water vapor, then natural processes could form some of the organic compounds found in living cells

                                                            ii.      Debate

1.      Today, some scientists think that the early atmosphere was mainly carbon dioxide, nitrogen, and water vapor.  Others believe it likely contained carbon dioxide and high levels of hydrogen.

2.      If true, this makes the Oparin-Haldane Hypothesis incorrect

e.      Alternative Theories

                                                              i.      Chemical reactions needed to form basic organic compounds occurred in deep sea vents where hot volcanic gases are released.

1.       Scientists have formed amino acids in experiments that simulate this environment. 

2.      It is highly unlikely that sea vents could form a meaningful amount of organic molecules.  The heat would destroy the molecules

                                                            ii.      Panspermia is a belief that life originated in outer space

1.      In 2008, organic compounds were found in a meteorite that landed in Australia

9.      The Evolution of Cells

a.      Protocells

                                                              i.      Sydney Fox created them in a lab

                                                            ii.      The first cell-like structures, contained amino acids that organized into spherical semi-permeable membranes that could grow and divide

                                                          iii.      Much more simpler than cells today

b.      First Cell – Bacteria  that was anaerobic heterotrophic prokaryote

                                                              i.      Anaerobic – no oxygen needed to get energy

                                                            ii.      Heterotrophic – must consume other organic compounds

                                                          iii.      Prokaryote – no nucleus or other organelles

c.       Some of the first cells evolved to create their own food (autotrophic)

                                                              i.      Produced much of the oxygen in the atmosphere today

                                                            ii.      Free oxygen is destructive (oxidation)

d.      Some of these cells evolved to use oxygen to create energy (aerobic) to protect themselves against destruction (oxidation)

e.      Anaerobic heterotrophic bacteria → aerobic bacteria → photosynthetic bacteria

110.  Endosymbiotic Theory

a.      The origin of mitochondria and chloroplasts

b.      A large anaerobic cell engulfed an aerobic prokaryote and formed a symbiotic relationship with it

                                                              i.      This engulfed cell became a mitochondria, making the new cell an aerobic eukaryote

c.       The new aerobic eukaryote evolved into animal and fungi cells

d.      An aerobic eukaryote engulfed a photosynthetic prokaryote which formed another symbiotic relationship becoming a chloroplast

                                                              i.      This new aerobic eukaryote that makes its own food became the first plant cells

11.   Taxonomy

a.      Classifying organisms into group

                                                              i.      Taxa (taxon-singular) – name of a group

b.      Carl Linnaeus

                                                              i.      Father of taxonomy created the taxa and organized living organisms according to their similarities

c.       Taxa order from most diverse to least diverse

                                                              i.      Kingdom, Phylum (Division in Plants), Class, Order, Family, Genus, Species

                                                            ii.      Kingdom has the most organisms; species has the fewest

                                                          iii.      Species – group of organisms that can interbreed and produce fertile offspring; fewest members; least inclusive

                                                           iv.      Genus – group of similar species

                                                             v.      Family – group of similar Genus

                                                           vi.      Order – group of similar Families

                                                         vii.      Class – group of similar Orders

                                                       viii.      Phylum – group of similar Classes

                                                           ix.      Kingdom – group of similar Phylums; has the most organisms; most inclusive

d.      If two organisms belong to the same Genus, then they also belong to the same taxa above Genus –Family, Order, Class, Phylum, and Kingdom.

e.      Binomial Nomenclature – a system of naming organisms

                                                              i.      Genus species

1.      Genus is capitalized; written first

2.      species is lowercase; written last

3.      Both are written in italics or underlined if handwritten

                                                            ii.      Acer rubrum is the Red Maple Tree

1.     
Acer is the Genus

2.      rubrum is the species

12.  Evolutionary Relationships

a.      Scientific names should indicate how closely related the organisms are

                                                              i.      If the organism has the same word for their Genus, then they are very closely related

13.  DNA Classification

a.      Carl Linnaeus used physical appearance and structure to classify organisms

b.      Using Gel electrophoresis, we now can look at organisms DNA to see how similar their DNA sequences are in order to determine how closely related they are

14.  Dichotomous Key -  a list of questions used to decide where organisms should be classified

15.  Viruses

a.      Not considered living because

                                                              i.      Cannot grow or develop carry out respiration

                                                            ii.      Can only reproduce inside a host cell

b.      Examples: Mumps, Measles, Chicken Pox, the Flu, a Cold, HIV (virus that causes AIDS)

c.       Cannot be treated by antibiotics because it is not living