BIOL111 Lectures 1-2

• 1. Energy transformation - transform energy to synthesize new molecules
• 2. Reproduce - make nearly faithful copies of themselves
• 3. Maintain homeostasis - regulate internal environment in response to external changes

• 1. light
• 2. inorganic compounds (H₂, H₂S etc.)
• 3. organic compounds (starch, fats etc.)

• "self-feeding"
• can make organic molecules usig inorganic compounds and outside energy

use light energy and CO₂ to make glucose

use chemical energy and CO₂ to make glucose

"different feeding"

• consume organic molecules as both energy source and carbon source to transform into other organic molecules
• examples: animals and fungi and many bacteria

• Use light as energy source but obtain carbon from food
• example: certain bacteria

• "without sex"
• no union of gametes
• little to no genetic difference

• union of gametes
• genetic difference between parents and offspring

genetic and resulting phenotpic change (observable property) in populations of organisms from one generation to the next

• brachiopod
• ginkgo biloba
• horseshoe crab
• coelocanth

• DNA analyses indicate that Neanderthals and Humans interbred
• DNA extracted from leg bones, now 60% of Neanderthal genome has been sequenced
• Found Neanderthal DNA fragments are scattered through genome of non-African ancestry

• Process:
• 1. mimic earth's early atmosphere (CH₄, N₂, NH₃, H₂, H₂O, CO₂)
• 2. zap with electricity
• 3. condense and analyze for simple organic compounds
• Found:
• all 5 bases in DNA and RNA
• 17/20 amino acids used in protein synthesis
• 3- and 6-carbon sugars

• 1. take early (pre-O₂) atmosphere and zap with lightning - form monomers (amino acids, nucleotides, sugars)
• 2. place monomers in locations favorable to condensation reactions (clay shores, hydrothermal vents, hot pools) - polymers (proteins, carbs, RNA/DNA, lipids)
• 3. RNA before DNA - simpler, acts as a catalyst
• 4. lipids naturally form bilayer spheres - encapsulae RNA providing more stable environment
• 5. self-replicating structure - nucleic acid inside and nucleotides on outside

~4.5 bya

~3.8 bya

~2.5 bya

1.5 bya

700 mya

542 mya

420 mya

~200,000 ya

• movement of continents - continental drift
• volcanic activity, meteorite collisions
• rise and fall of sea levels
• changing temp
• increase in O₂

Produced an increase in O₂

• early atmosphere had no oxygen
• light energy splits water, organisms used free electrons to reduce carbon dioxide and build organic molecules
• oxygen is a waste product
• leads to aerobic respiration
• leads to more complex life (eukaryotic, multicellular)

Cyanobacteria - photosynthetic prokaryotes, formed stromatolites

• lasted from ~4.5bya to 542 mya
• largely unicellular, prokaryotes
• life confined to oceans

• "old life"
• lasted from 542mya to 251mya

• "middle life"
• lasted from 251mya to 65mya

• "new life"
• from 65mya-present

• (layered cyanobacterial concretions
• in the precambrian era

late precambrian (last 1/3 of era)

larger soft-bodied animals

late precambrian era (last 1/3)

begins with Cambrian explosion - relatively rapid diversification of multicellular life

• In British Columbia
• discovered in 1909
• best fossil site of cambrian animals
• excellent preservation of soft and hard parts

arthropods

• During paleozoic era
• 488-444mya
• radiation of marine organisms (like brachiopods and mollusks)
• ended with massive extinction (75% of species eliminated) because of sea level and ocean temperature drop

• during mid paleozoic era
• 444-416mya
• marine life rebounded
• animals swim and feed above ocean bottom, jawless fishes diversified
• colonization of land (simple plants, arthropods like millipedes and scorpions among firtst)

• during mid-paleozoic
• 416-359mya
• "age of the fishes"
• in oceans: fishes diversify - evolve jaws, loss of heavy armour, limbs & radiation of corals and shelled cephalopods
• on land: common are large club mosses, ferns and horsetails & first seed plants (gymnosperms) & spiders and insects
• ends with mass extinction (75% of marine life wiped out)

• during late paleozoic
• 359-297 mya
• "age of amphibians or coral"
• amphibians diversify and are abundant
• land dominated by giant swamp forests (ferns and horsetails)
• insects evolve flight
• crinoids abundant in oceans
• amniotic egg evolves

• a shelled egg with extra-embryonic membranes
• key adaptation that allowed organisms (like reptiles, birds, and mammals) to reproduce on land
• modifications exist across amniotic animals

• during late paleozoic era
• 297-251 mya
• reptiles diversify and begin to dominate over amphibians - many new lineages evolve
• largest mass extinction in earth's history (96% of life became extinct)
• oxygen concentrations dropped by 50%

• during mesozoic era
• 251-200 mya
• early dinosaurs
• first mammals
• diversification of invertebrates
• ends with mass extinction (~65% of species go extinct)

• during mesozoic era
• 200-145 mya
• large terrestrial herbivores and predators are dinosaurs
• flying reptiles appear (pterosaurs)
• first fossils of flowering plants
• radiation of ray-finned fishes

• during mesozoic era
• 145-65 mya
• dinosaur continue to diversify
• first snakes appear
• mammals radiate, but most small

• Probable cause - meteorite impact
• On land all animals >25kg became extinct, plus many insects
• Probably died because of lack of food

• 1. High concentrations of iridium (rare on earth, but abundant  in meteorites)
• 2. Crater loacated off Yucatan, 180km in diameter and based on this size, estimate meteorite collision released 100 megatonnes of high explosives

• 65mya - present
• "age of mammals"
• starts with the recovery from mass extinction
• radiation of birds
• radiation of flowering plants (angiosperms - evolve symbioses with nitrogen fixing bacteria, insects)
• radiation of mammals - hominids

About 200,000 years ago