Module 5 & 6 Flashcards
Earth was formed ____ billion years ago
4.55
The ‘big bang’ took place ___ bya.
4.6
How was Earth’s outer crust formed?
Earth cooling
How did oceans form on primitive Earth?
oceans accumulated from water vapour in depressions on Earth’s surface
True or false? Ancient Earth had minimal oxygen.
False. Ancient Earth has NO oxygen
What important changes took place in Earth’s second atmosphere?
CO2, nitrogen, probably methane and ammonia emitted from volcanic vents
What were the four major milestones in the formation of the building blocks of life?
(1) Formation of organic nucleotides and amino acids
(2) Monomers ^^ became polymers
(3) Polymers become enclosed in a membrane
(4) Membrane bound polymers acquire key cell properties (nucleus and organelles to function on its own)
Summarize the theory proposed independently by Oparin and Haldene.
Hint: soup
Organic molecules formed spontaneously from inorganic compounds in a primordial soup ( the aqueous solution of organic compounds that accumulated in primitive water bodies of the early Earth).
Describe the Reducing hypothesis and the Miller and Urey Experiment.
An apparatus was used to simulate the water cycle, boiling water to mimic evaporation. Water vapour combines with methane, hydrogen, and ammonia to imitate the atmosphere. A condensor cools the atmosphere and produces condensation to imitate rain. Sparks were added to stimulate lightning.
Amino acids and other compounds were produced.
What is the Extraterrestrial Hypothesis?
Theory for the origin of the first organic molecules stating they came on a meteorite
Describe Wachtershauser’s Deep Sea Vent Hypothesis for the origin of organic molecules.
Hot vents in the bottom of the ocean created perfect conditions for water, metals, methane gas, and hydrogen sulphide to spontaneously form organic compounds, using energy from the vents
What substrate did the transformation of monomers to polymers take place?
clay surfaces or tidal ephemeral pools
What is a protobiont?
First nonliving enclosed boundary structures (looks like a cell but does not have cellular properties, abiotic, contains cellular molecules)
_____ (lipid spheres) may have led to the development of true cells
Liposomes
What cellular properties did membrane bound polymers aquire?
Formation of RNA/DNA and metabolism
What was the first life on Earth like?
Sulfur bacteria living in an oxygen-less atmosphere and hot ocean with few small landmasses
Compare aerobic and anaerobic metabolism.
Aerobic (with oxygen) metabolism
Anaerobic (without oxygen) metabolism
When do we see a rise in oxygen levels and why?
2.5 bya; cyanobacteria with photosynthetic abilities began producing oxygen 3.5 bya
What is the reason for the delay in the rise of oxygen levels
Banded iron formations; oxidation of ferrous iron produced ferric iron and sediments that contained the oxygen and settled
When did the first Eukaryotic cells come into existence and what era was this?
2.0-2.5 bya; Archaean era
What ensures that cells are clones and do not compete with each other in a multicellular organism?
Zygotes
What is endosymbiosis theory?
The nucleus, chloroplasts, and mitochondria were consumed and later evolved into organelles
What are seven types of evidence for Endosymbiosis theory?
Mitochondria and chloroplasts…
Morphology similar to bacteria and archaea; functions similar to aerobic and photosynthetic bacteria; divide by binary fission; contain their own DNA; contain compete transcription and translational machinery (RNA); have electron transport chains; and RNA sequences belong on bacterial branch of tree of life
True or false?
Cyanobacteria occur as endosymbionts in the cells of modern organisms.
True
Endosymbiosis resulted in a _______ of eukaryotic life
diversity
What are the two possible origins of multicellular animals?
Individuals form a colony and single cell divides and stays stuck together
What are the three possible reasons for the diversification of eukaryotes?
Genetic changes and environmental changes or predation influencing evolution
When did multicellular eukaryotes arise?
1.5 bya in the Proterozoic Eon
Multicellularity is associated with the increase in what three things?
size, complexity, and specialization
What is the Cambrian explosion and its significance?
The biological big bang characterized by warm, wet climate and oxygen levels above key threshold that gave rise to the evolution of most major invertebrate body forms
What are three potential reasons for the large increase in animal diversity in the Cambrian period?
(1) Rising oxygen levels in the atmosphere
(2) evolutionary advances just prior that gave rise to subsequent animals
(3) Predators a key driver of evolutionary biodiversity
In what era and period did ancestral plants and arthropods invade land?
Paleozoic era; Ordovician period
What was the first terrestrial invertebrate?
myriapods (similar to centipedes) with spiracles for air breathing
What was the first land plant?
Bryophytes (liverworts, hornworts, and mosses)
What are the 5 key adaptations for living on land?
Obtaining water, preventing water loss, obtaining sufficient energy, coping with variable temperatures, and the ability to support their own weight
Plants have changed what four things in Earth’s history?
Atmospheric chemistry, climate, production of soils, and evolution of other consumer organisms
What seven major environmental changes drive evolution?
climate/temperature, atmosphere, flooding/weather events, volcanic eruptions, meteor impacts, shifting land masses, and glaciation
What is functional extinction?
only a small number of individuals are left and the population is no longer viable
What is the natural average extinction rate?
species typically survive 1-10 million years; 9% of species per million years
What was the impact of the meteor of the Alvarez Asteroid Theory?
180 km crater, volcanic activity and chemical reactions, tsunamis, rapid increase in temperature, fires, acid rain, dust in atmosphere, and reduced photosynthesis
