Life in the Precambrian Prelude to Us
Life A Short Summary Slime Mold Tardigrade
What is Life? Composed of organic compounds Resistance to entropy (disorder) –Requires energy (must be able to gather and process (metabolize) energy) Ability to maintain a controlled environment –Requires ability to be isolated from environment Information storage Self replication –Including ability to pass on information Ability to adapt to its environment –Undergoes biological evolution
Life on Earth: Organic Compounds Human AlfalfaBacteria Oxygen(O)62.8%77.9%73.7% Carbon (C)19.4%11.3%12.1% Hydrogen (H)9.3%8.7%9.9% Nitrogen (N)5.1%0.8%3.0% Phosphorous (P)0.6%0.7%0.6% Sulfur (S)0.6%0.1%0.3% Carbon is found in all organic compounds Important Elements
Life on Earth: Organic Compounds Types of Organic Compounds 1. Lipids - (H,C (hydrocarbons)) Fats and Oils cell membranes & energy storage 2. Carbohydrates - (C, H, O) Sugars, Starches and Cellulose energy storage & structure
Life on Earth: Organic Compounds Types of Organic Compounds 3.Amino Acids Proteins - (C, H, O, N, S) Enzymes - catalysts for chemical reactions also Hair, silk, fingernails, etc. 4. Nucleic Acids - (C, H, O, N, P) DNA (Deoxyribonucleic Acid) RNA (Ribonucleic Acid) store & transfer genetic information
Organic Compounds Cells Organisms Not Alive Alive
Life on Earth: Controlled Environment Cell
Eukaryote Prokaryote
Prokaryote - E. coli Small (<5 m) No nucleus Unicellular
Eukaryote - Frog & Ameba Larger (> 10 m) Nucleus Organelles Cytoskeleton Uni- and multi-cellular
Life on Earth: Controlling Entropy Gathering Energy Photosynthesis Carbon Dioxide + Water + Sunlight --> Sugar + Oxygen Chemosynthesis Hydrogen Sulfide + Carbon Dioxide + Water + Oxygen + Geothermal Heat --> Sugar + Sulfuric Acid
Chloroplasts
Life on Earth: Controlling Entropy Releasing Energy Respiration Sugar + Oxygen --> Carbon Dioxide + Water + Energy
Mitochondria
Life on Earth: Information Storage DNA - Deoxyribonucleic Acid RNA - Ribonucleic Acid
Chromosomes
Human Chromosomes
Chromosome Numbers
Life on Earth: Information Storage DNA - Deoxyribonucleic Acid RNA - Ribonucleic Acid
DNA RNA Protein Replication Transcription Translation
The Universal Genetic Code AUG - UGC - CAU - AAA - UGA Start - Cysteine - Histidine - Lysine - Stop
DNA Translation Instructions: How to make proteins from amino acids
Genetics Produce Variety
Life on Earth: Self Replication
Cloning (Mitosis)
Life on Earth: Self Replication Sexual Reproduction (Meiosis) Sperm & Egg Fertilization (Combination of genes from 2 parents) Complete Organism
Life (as we know it) Made of organic compounds Organized into cells (controlled environment) Cells interacts with environment to collect nutrients/energy and remove waste Has a mechanism (DNA) to store information Can replicate itself & pass on information Can evolve and adapt to changing environment
Causes of Diversity and Evolution of Life on Earth Charles Darwin Alfred Russell Wallace
Causes for Diversity of Life 1.All populations have the potential to increase in size 2.Many populations retain a constant size Many individuals die young 3. Individuals in a population differ in their abilities Some of these abilities affect survival 4.Best adapted individuals are most likely to survive and produce offspring (Natural Selection) “Abilities” are passed on to offspring (Genetics) 5.Over time the “abilities” of the population shift to include advantageous traits (Evolution)
Note: Natural Selection Affects Individuals Evolution Affects Populations
Net Result: Populations change with time to become better adapted to their environment (Evolution)
Example: Microbe Resistance Apply Antibiotic Survivor’s with Resistance Reproduce
How does it Work? Variation in the Gene Pool of a Population
How does it Work? Variation is a result of (1) Mutations and (2) Sex Errors occur in DNA Replication On average 1:10, ,000 genes per individual per generation Increased by exposure to radiation, etc. Most Mutations are bad or at least neutral What is “good” depends on environmental conditions
Evidence for Evolution
Evidence for Evolution: Fossils & Faunal Succession
Evidence for Evolution: Analogous Structures
Evidence for Evolution: Homologous Structures
Evidence for Evolution: Embryology
Evidence for Evolution: Biochemistry of Life
Evidence for Evolution: Gene Sequencing
Evidence for Evolution: Artificial Selection
Evidence for Evolution: Modern Examples
Some Interesting Effects of Evolution
Evolution & Psuedoextinction Species A Species B Through time Species A evolves into Species B In effect, Species A goes extinct
Extinction Species A Sometimes a species cannot adapt fast enough to environmental change or competition
Moa No moa, no moa, In old Ao-tea-roa. Can’t get ‘em. They’ve et ‘em. They’ve gone and there ain’t no moa!
Extinctions through time
Evolution & Speciation Species A Species B Species C Species A is separated into 2 isolated populations, each affected by different environmental conditions In effect, Species A goes Extinct
Speciation of Hawaiian Honeycreepers
Diversity Increases
Convergent Evolution
Coevolution: Plants and Pollinators
Coevolution: Predator/Prey
Life (as we know it) Made of organic compounds Organized into cells (controlled environment) Cells interacts with environment to collect nutrients/energy and remove waste Has a mechanism (DNA) to store information Can replicate itself & pass on information Can evolve and adapt to changing environment
Origins? Where did organic compounds come from? How did they form? How did cells form? What formed the first membrane? How did the machinery of cells (ability to perform respiration and photosynthesis) come about? Where did DNA come from? Was it the first form of information storage? How were the first cells able to replicate? How did they adapt to changing environment?
Major Steps in the Precambrian Evolution of Life 1.Origin of Life ( Gyrs) 2.Photosynthesis (3.5 Gyrs) 3.Aerobic (Oxygen-based) Respiration (3-2 Gyrs) 4.Eukaryotes / Endosymbiosis ( Gyrs) 5.Sex / Death (1 Gyrs) 6.Multicellular Life (800 Myrs) 7.Skeletons & Shells (600 Myrs) * All dates are approximate
Evolvovision Evolvovision (Ray Troll)