TOPIC3
BRIEF HISTORY OF LIFE:
KINGDOMS & LANDMARKS
5 KINGDOM SYSTEM
(WHITTAKER 1959)
KINGDOMS
MONERA
PROTISTA
PLANTAE
FUNGI
ANIMALIA
BASED ON
CELL ORGANIZATION: PROKARYTOTES VS. EUKARYOTES
CELL WALL STRUCTURE: YES VS. NO; COMPOSITION
NUTRITION: AUTOTROPHS VS. HETEROTROPHS
[TABLE 27.1]
MODE OF NUTRITION = ENERGY SOURCE + CARBON SOURCE
AUTOTROPH
PHOTOAUTOTROPH = LIGHT+ CO2
CHEMOAUTOTROPH = INORGANIC CHEMICALS + CO2
HETEROTROPH
PHOTOHETEROTROPH = LIGHT + ORGANIC CHEMICALS
CHEMOHETEROTROPHS = ORGANIC CHEMICALS + ORGANIC CHEMICALS
3 DOMAIN SYSTEM
(WOESE 1978)
DOMAIN ( = TAXON ABOVE KINGDOM)
BACTERIA (= EUBACTERIA)
ARCHAEA (= ARCHAEBACTERIA)
EUKARYA (= ALL EUKARYOTES)
BASIS FOR 3 DOMAIN SYSTEM
[TABLE 27.2]
SOME SHARED FEATURES OF ARCAHEA & EUKARYA
SHARED SIGNATURE SEQUENCES IN RIBOSOMAL RNA
INTRONS (NON-CODING PARTS OF GENES)
LACK PEPTIDOGLYCAN IN CELL WALLS
UNIVERSAL ANCESTOR
DNA (MOLECULAR MEMORY)
RIBOSOMES WHERE mRNA => PROTEINS
MEMBRANES OF LIPIDS & PROTEINS
ATP (ENERGY PROCESSING)
GLYCOLYSIS
ANAEROBIC METABOLISM
CHEMOAUTOTROPH
HYPERTHERMOPHILIC & HALOPHILIC
8 KINGDOM SYSTEM
KINGDOMS
BACTERIA
ARCHAEA
ARCHAEZOA
PROTISTA (PROTOZOA)
CHROMISTA
PLANTAE
FUNGI
ANIMALIA
3 DOMAINS PLUS 8 EUKARYOTE KINGDOMS
DOMAIN
BACTERIA
ARCHAEA
EUKARYA
KINGDOM
ARCHAEZOA
EUGLENOZOA
ALVEOLATA
STRAMENOPILA
RHODOPHYTA
PLANTAE
FUNGI
ANIMALIA
MAJOR METABOLIC ADVANCES
OXYGENIC PHOTOSYNTHESIS
CO2 + 12 H2O + LIGHT => C6H12O6 + 6 O2 + 6 H2O
ELECTRON TRANSPORT CHAIN & CHEMIOSMOSIS
(= PRODUCTION ON ATP USING ENERGY OF HYDROGEN GRADIENTS
ACROSS MEMBRANES)
AEROBIC RESPIRATION
C6H12O6 + 6 O2 => 6 CO2 + 6 H2O + ENERGY (ATP + HEAT)
ELECTRON TRANSPORT CHAIN & CHEMIOSMOSIS
OXYGEN = TERMINAL ELECTRON ACCEPTOR
HIGHLY EFFICIENT
MULTICELLULARITY: ADVANTAGES & DISADVANTAGES
a. CELLULAR SPECIALIZATION
BENEFITS: DIVISION OF LABOR
COSTS: CO-ORDINATION
b. GREATER SIZE
BENEFITS: MORE RESITANT & STABLE
NEW RESOURCES & LIFESTYLES
COSTS: PROCESSES RELATED TO SURFACE AREA AFFECTED REQUIRE TRANSPORT MECHANISMS
c. LONGER GENERATION TIME
BENEFITS: POSTPONE OR REPEAT REPRODUCTION
COSTS: EXINCTION PRONE
ORIGINS OF MULTICELLUARITY: 2 MODELS
a. SYNCYTIAL MODEL
PRECURSOR = LARGE SINGLE CELL WITH MULTIPLE NUCLEI
EXAMPLES =CILIATE PROTOZOANS
PLASMODIAL SLIME MOLD
"PERFECTION" = MEMBRANES FORM TO COMPARTMENTALIZE FUNCTIONS
b. COLONIAL MODEL
PRECURSOR = AGGREGATES OF GENETICALLY IDENTICAL CELLS SPECIALIZED FOR DIFFERENT FUNCTIONS
EXAMPLES = COLONIAL PROTISITS
AUTOTROPHS & HETEROTROPHS
ALGAE
CHOANOFLAGELLATES
CELLULAR SLIME MOLD
"PERFECTION" = CELLS BECOME HIGHLY SPECIALIZED & TOTALLY INTER-DEPENDENT
Cambrian Explosion: WHY?
545 - 525 mybp (0.54 - 0.52 Bybp)
SUDDEN APPEARANCE OF MODERN ANIMAL PHYLA
REPLACE EDIACARAN FAUNA
CRITICAL OXYGEN LEVELS
IMPROVED ENVIRONMENTAL CONDITIONS VS. "SNOWBALL EARTH"
CHALLENGING ENVIRONMENTAL CONDITIONS
NEW GENE COMPLEXES CONTROLLING DEVELOPMENT
EVOLUTION OF HARD BODY PARTS
GREATER GENETIC FLEXIBILITY THAN PRESENT
GREATER ECOLOGICAL OPPORTUNITIES THAN PRESENT
MAJOR EVENTS IN TERRESTRIAL HABITATS
(MILLIONS OF YEARS BEFORE PRESENT = 10 6)
MYBP EVENT
475 1ST LAND PLANTS
425 FUNGI TEAM WITH PLANTS
425 TERRESTRIAL ARTHROPODS
360 1ST TERRESTRIAL VERTEBRATES [TETRAPODS]
360 1ST VASCULAR PLANTS WITH SEEDS
310 1ST AMNIOTES [VERTEBRATES WITH TERRESTRIAL EGGS]
245 PERMIAN EXTINCTION
220 1ST MAMMALS
130 1ST FLOWERING PLANTS [ANGIOSPERMS]
65 CRETACEOUS EXTINCTION => MODERN ECOSYSTEMS
FIGURES (KINGDOMS & LANDMARKS)
1.10; 5.26; 6.6; 7.4; 7.5; 7.7; 7.8; 7.18; 7.28; 7.29; 7.30; 9.16; 10.14; 12.11; 25.4; 25.5 25.6; 26.3; 26.9; 26.10; 27.1; 27.8; 27.11; 28.1; 28.3; 28.8; 28.9; 28.12; 28.14; 28.20; 28.25; 28.26; 29.3; 29.10; 30.10; 31.2; 32.7; 33.2; 33.33; 34.14; 34.19; 35.4; 42.2; 52.3
TABLES: 25.1 & 27.2; Page 505