TOPIC 3
A BRIEF HISTORY OF LIFE
I. ORIGINS OF LIFE
A. MAJOR EVENTS IN THE EARTH’S HISTORY
B. 4 STAGES: FROM ABIOTIC PRECURSORS TO LIVING CELLS
II. PROKARYOTES & EUKARYOTES
A. CHARACTERISTICS OF EACH CELL TYPE
B. ORIGIN OF EUKARYOTIC CELL
III. DOMAINS & KINGDOMS: THE HIGHEST TAXONOMIC CATEGORIES
A. 5 KINGDOM SYSTEM
B. 3 DOMAIN SYSTEM
C. 8 KINGDOM SYSTEM
IV. KEY EVENTS IN EUKARYOTE EVOLUTION
A. OXYGENIC PHOTOSYNTHESIS & AEROBIC RESPIRATION
B. MULTICELLULARITY
C. CAMBRIAN EXPLOSION
D. COLONIZATION OF TERRESTRIAL HABITATS
E. ORIGIN OF MODERN ECOSYSTEMS
MAJOR EVENTS IN THE EARTH’S HISTORY
(BILLIONS OF YEARS BEFORE PRESENT = 10 9)
BYBP EVENT
4.5 EARTH FORMS
[4.0 EARTH SOLDIFIES]
3.8 1ST CHEMICAL EVIDENCE OF LIFE
3.5 1ST PROKARYOTE FOSSILS
[1ST FOSSIL EVIDENCE OF LIFE]]
2.5 ATMOSPHERIC OXYGEN ACCUMULATES
[PHOTOSYNTHESIS]
1.7 1ST EUKARYOTE FOSSILS
1.0 1ST MULTICELLULAR FOSSILS
[ALGAE]
0.7 1ST (MULTICELLULAR) ANIMAL FOSSILS
0.54 1ST FOSSILS OF MOST ANIMAL PHYLA
0.47 COLONIZATION OF LAND
[PLANTS, FUNGI & ANIMALS]
4 STAGES: FROM ABIOTIC PRECURSORS TO LIVING CELLS
STAGE 1.: ABIOTIC SYNTHESIS OF CARBON MONOMERS
STAGE 2: MONOMERS FORM CHAINS = POLYMERS
STAGE 3. PROTOBIONTS FORM
[AGGREGATES OF ABIOTICALLY PRODUCED ORGANIC MOLECULES THAT EXHIBIT
SOME PROPERTIES OF LIFE]
STAGE 4. MECHANISMS OF HEREDITY EVOLVE
[= MOLECULAR MEMORY]
CONDITIONS ON EARLY EARTH
WATERY
LOWER TOTAL SOLAR RADIATION
BUT MORE ULTRAVIOLET LIGHT
DIFFERENT ATMOSPHERIC COMPOSITION
CARBON DIOXIDE = HIGH
FREE OXYGEN = ABSENT
HIGH SURFACE TEMPERATURES
3 TYPES OF PROTOBIONTS
LIPOSOME
MICROSPHERE
COACERVATE
MOLECULAR MEMORY
MODERN LIFE
DNA => RNA => PROTEINS [ENZYMES & STRUCTURE]
PROTOLIFE
RNA => PROTEINS
CHARACTERISTICS OF PROKARYOTIC & EUKARYOTIC CELLS
PROKARYOTES / EUKARYOTES
SMALL / LARGE
(1 - 10 m m) / (10 - 100 m m)
NO MEMBRANE-BOUND NUCLEUS / MEMBRANE-BOUND NUCLEUS
SIMPLE DNA IN RING / COMPLEX DNA IN MULTIPLE CHROMOSOMES
LITTLE INTERNAL STRUCTURE / COMPLEX INTERNALLY
NO MEBRANE-BOUND ORGANELLES / MEMBRANE-BOUND ORGANELLES
CELLULAR STRUCTURES OF EUKARYOTES
ENDOMEMBRANE SYSTEM
ENDOPLASMIC RETICULUM
GOLGI APPARATUS
LYSOSOMES
MITOCHONDRIA
PLASTIDS
(CHLOROPLAST)
CYTOSKELETON
ORIGIN OF EUKARYOTIC CELL
1. INVAGINATION OF PLASMA MEMBRANE = ORIGIN OF ENDOMEMBRANE SYSTEM
2. ENDOSYMBIOSIS = ORIGIN OF MITOCHONDRIA & PLASTIDS
ENDOSYMBIOSIS = AN ECOLOGICAL RELATIONSHIP BETWEEN ORGANISMS OF 2
DIFFERENT SPECIES THAT LIVE TOGETHER IN DIRECT CONTACT; THE SYMBIONT
ACTUALLY LIVING INSIDE THE HOST
REQUIRES HOST & SYMBIONT
ENDOSYMBIOSIS: ORIGIN OF MITOCHONDRIA
HOST: LARGE (PROKARYOTIC) CELL WITH ANAEROBIC METABOLISM
plus
SYMBIONT: SMALL PROKARYOTIC CELL WITH AEROBIC RESPIRATION (EUBACTERIUM)
ENDOSYMBIOSIS: ORIGIN OF CHLOROPLASTS
HOST: LARGE EUKARYOTIC CELL
plus
SYMBIONT: SMALL PROKARYOTIC CELL CAPABLE OF OXYGENIC PHOTOSYNTHESIS (CYANOBACTERIUM)
ORIGINS OF MUTUALISM
[A SYMBIOTIC RELATIONSHIP IN WHICH BOTH HOST & SYMBIONT BENEFIT]
PROPOSED ROUTE 1
LARGE HETEROTROPHIC HOST CELL CONSUMES SMALL PROKARYOTE
[HETEROTROPH = ORGANISM THAT OBTAINS ORGANIC COMPOUNDS BY EATING OTHER ORGANISMS OR THEIR BY-PRODUCTS]
CONSUMPTION VIA PHAGOCYTOSIS
= CELLULAR UPTAKE OF PARTICLES BY LOCALIZED REGIONS OF THE PLASMA MEMBRANE THAT SURROUND THE PARTICLE & PINCH OFF IN FORM AN INTRACELLULAR VESICLE
SYMBIONT SURVIVES INTERNALLY
PROPOSED ROUTE 2
LARGE HOST CELL PARASITIZED INTERNALLY BY SMALL PROKARYOTE
PARASITISM EVOLVES INTO MUTUALISM
ORIGINS OF MUTUALISM
SYMBIONT BENEFITS
SAFE, STABLE ENVIRONMENT
METABOLIC PRODUCTS FROM HOST
HOST BENEFITS
NOVEL METABOLIC PATHWAYS OF SYMBIONT
METABOLIC PRODUCTS OF SYMBIONT
FACULTATIVE RELATIONSHIP BECAME OBLIGATE RELATIONSHIP
DNA CONTROLLING STRUCTURE & FUNCTION OF MITOCHONDRIA &
CHLOROPLASTS NOW PART OF NUCLEAR DNA
EVIDENCE FOR ENDOSYMBIOSIS MODEL
1. OTHER ENDOSYMBIOTIC RELATIONSHIPS EXIST TODAY
2. MITOCHONDRIA & CHLOROPLASTS RESEMBLE BACTERIA
3. PRIMITIVE EUKARYOTES LACK MITOCHONDRIA
SHARED FEATURES: MITOCHONDRIA & CHLOROPLASTS WITH BACTERIA
SIZE
DNA IN RING
REPLICATE VIA BINARY FISSION
INFOLDING OF OUTER MEMBRANE
CRISTAE IN MITOCHONDRIA
THYLAKOID MEMBRANE IN CHLOROPLASTS
RIBOSOME STRUCTURE & RIBOSOMAL RNA SEQUENCES
FEATURES OF EUKARYOTIC CELL NOT EXPLAINED BY CURRENT MODEL
MICROTUBULES
FLAGELLA & CILIA
ENLARGED GENOME & MITOSIS
SEXUAL REPRODUCTION & MEIOSIS
TOPIC 3
BRIEF HISTORY OF LIFE
TEXT (Pages, entire topic):
466 - 473 (events in geologic time)
490 - 500 (origin of life & major lineages)
502 - 503 (prokaryote evolution)
509 - 513 (metabolism & prokaryote phylogeny)
522 - 526 (origin of eukaryotes)
542 - 543 (origin of multicellularity)
548 - 549 (plant phylogeny)
571 (global impact of plants)
595 - 596 (Cambrian explosion)
TOPIC 3
BRIEF HISTORY OF LIFE : ORIGINS
FIGURES (for first 1/2 of topic):
FIG. 5.2; 5.7; 5.13; 5.26; 5.27; 7.1; 7.4; 7.7; 7.8; 7.9; 7.16; 7.11; 7.12; 7.13; 7.14; 7.17; 7.18; 7.20; 7.22; 7.24; 9.16; 12.10; 12.11; 26.2, 26.3; 26.4; 26.5; 26.6; 26.7; 26.9; 27.1; 28.2; 28.7
TABLE 25.1
TOPIC 3 - GLOSSARY (entire topic)
adaptive radiation, agnathan, aerobic metabolism, amino acid, amniote, anaerobe, Animalia, Archaea, Archezoa, autotroph, Bacteria, Burgess Shale, Cambrian Period, Carboniferous Period, Cenozoic, chemoautotroph, chemoheterotroph, chloroplast, choanoflagellate, Chromista, coacervate, colonial hypothesis, Cretaceous Period, cyanobacteria, cytoskeleton, Devonian, Domain, electron transport chain, Eight Kingdom system, endomembrane system, endoparasite, endoplasmic reticulum, endosymbiosis, Eukarya, eukaryotes, Five Kingdom System, Fungi, glycolysis, Golgi complex, greenhouse effect, halophilic, heterotroph, hyperthermophilic, Kingdom, liposome, lycopod, lysosome, Mesozoic Era, methanogen, microsphere, microtubule, Miller-Urey apparatus, mitochondrion, Monera, monomer, multicellularity, mutualism, mycorhizae, nucleic acid, Ordovician Period, oxygenic photosynthesis, ozone layer, Paleozoic Era, peptidoglycan, Permian Period, photoautotroph, photoheterotroph, Plantae, plastids, polymer, primary producer, prokaryotes, Protista, protobiont, reducing atmosphere, Silurian, slime mold, Snowball Earth Theory, stromatolite, syncytial hypothesis, Tertiary Era, Three Domain system, universal ancestor, Whittaker, Woese.