(the first 3 A.S. on radioisotope dating are covered in this section)

Online study guide for IB-Biology Evolution section

Lecture notes for evolution here and here


2/3/12
  • evolution reassessment
  • read pg. 208-210 in book

HW:

  • study for human evolution test
  • read pg. 208-210


2/6/12

Human Evolution test, not including information on radioisotope dating


The vast amount of time that has passed since the formation of the earth is difficult for most people to grasp. The following link and image illustrate the stages in the developmental stages of the earth itself and the evolution of life from unicellular prokaryotes to complex multicellular organisms.

Geologic Time
Virtual Dating (14C)
K/ Ar dating tutorial
625px-Geologic_Clock_with_events_and_periods.svg.png
Image Legend: Ma (million years); Ga (billion years)

Exploring the Origins of life
Readings on Early Earth History (Website from O.S.U. Mansfield)

2/7/12

Radioisotope dating cont.,

C-14-carbon-dating-process_full_size.jpg

During radioisotopic decay, 1 half-life = the time necessary for 1/2 of the original radioactive parent compound to decay to its daughter compound. In this example, Carbon-14 decays into Nitrogen-14 via beta-decay.
Radioactive-decay.jpg
K-Ar_decay_curve.jpg


K-Ar dating:
Khan Academy

C-14 dating:
Khan Academy video 1
Khan Academy video 2

2/8/12
Senior Capstone Release Day.


2/9/12
Conditions on Earth
Four processes needed for the spontaneous origin of life on Earth
What is life? How did life begin?
recipe_for_life_image.jpg

1. Assembly of simple organic molecules
prebiotic_earth_conditions_image.jpg

Miller and Urey Experiment
miller-urey_expt_image.jpg

Site of possible organic beginnings
Hydrothermal_vent_biotic_zones_image.gif

Murchison meteorite
Murchison_meteorite_image.jpg

Some of the compound classes detected in the Murchison carbonaceous chondrite. The specific examples are amino acids (l-alanine), carboxylic acids (propionic acid), hydroxyacids (lactic acid), sugar-related compounds (dihydroxyacetone), amines (propylamine), amides (pyroglutamic acid), nitrogen heterocycles (uracil), sulphur heterocycles (benzothiophene), aromatic hydrocarbons (2-methylnaphthalene), aliphatic hydrocarbons (pentane), terpenes (camphor). Note that by far the majority of organic matter in carbonaceous chondrites is present as a macromolecular material which contains some of these structures linked together, but is mostly made up of aromatic hydrocarbons.
Organic_comoounds_isolated_from_Murchison_meteorite.gif

Microfossils from the Murchison meteorite
microfossils_from_the_murchison_meteorite.jpg

HW: Go to the Miller and Urey Experiment website and conduct experiments to test the components necessary to form simple organic monomers.
Reading: Chapter 4 from Raven, Johnson Text (Pages 62-63; 65-69).


2/10/12
Origin of self-replicating molecules
Scientists develop self-replicating molecule in lab

RNA as the original hereditary molecule?
651px-Ribosome_mRNA_translation_en_svg.png
220px-RNA_chemical_structure.GIF

Protobionts (Coacervates and microspheres)
coacervates_image.jpg
Coacervates: lipid droplet enclosing organic molecules

microsphere_image.jpg
microspheres: protein spheres surrounding organic moleculess

early-prebionts_in_coacervates.jpg
Diagram of a protobiont


HW: Read Chapter 4 (pages 70-76) from Raven, Johnson text.

2/13/12
Review? Radioisotope dating/origins of organic molecules/protobionts.
RNA and the development of protobionts (for review, read the sections "Understanding the RNA World" and ""Building a Protocell".

Evolution of prokaryotes:
From protobionts to prokaryotes

This paper gives a good, if technical, description of the evolution of prokaryotes including archaebacteria and eubacteria during the early periods of Earth's development.

Archaebacteria vs. Eubacteria
(Differences between archaebacteria and eubacteria)

Archaebacteria (video)

Definition
noun, singular: archaebacterium
Unicellular microorganisms in the domain Archaea, which is genetically distinct from bacteria and eukaryotes, and often inhabiting extreme environmental conditions. Examples of archaebacteria include halophiles (microorganisms that may inhabit extremely salty environments), methanogens (microorganisms that produce methane), and thermophiles (microorganisms that can thrive extremely hot environments).
They evolved separately from eubacteria and eukaryotes. They are similar to eubacteria in being prokaryotes and lacking distinct cell nuclei. They differ in terms of ribosomal structure, the possession of introns and in membrane structure or composition. They are similar to eukaryotes such that archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes: notably the enzymes involved in transcription and translation. (© Biology-Online.org.)

Eubacteria
Definition
noun, singular: eubacterium
Literally means true bacteria, which includes all bacteria except for archaebacteria. These bacteria form the domain Bacteria, previously called domain Eubacteria. It is one of the three domain systems, the other two being domain Archaeabacteria (now Archaea) and domain Eukarya (the eukaryotes). Eubacteria are prokaryotic organisms, as characterized by the lack of a membrane-enclosed nucleus, predominantly unicellular, with DNA in single circular chromosome, and have peptidoglycan on cell wall when present. They include most of the familiar bacteria of medical and economic importance such as E. coli, Staphylococcus , Salmonella, Lactobacillus, Nitrosomonas, Streptomyces, etc.(© Biology-Online.org.)

archaebacteria_vs_eubacteria.png

2/14/12
origin of cyanobacteria and evolution of photosynthesis
development of an oxygen rich atmosphere
cyanobacteria_image.jpg
Images of a variety of cyanobacteria

cyanobacteria_em_image.jpg
EM image of cyanobacteria structure


origin of eukaryotes - development of organelles and nucleus from primitive infolding of bacterial membranes
organelles and endosymbiosys video
origins_of_organelles_Page_02.jpg
origins_of_organelles_Page_01_Page_04.jpg
Mitochondria_image.jpg
chloroplasts_image.jpg


HW: Read the paper on evolution of prokaryotes. Bring questions to class tomorrow.

2/15/12: Test on radioisotopic dating and origins of life.
Online study guide for IB-Biology Evolution section