Biosphere 1 Flashcards
What is homeostasis?
Boundaries. The inside is different from what is outside
internal conditions have to be maintained
What is the structure like in life?
highly organised (not necessarily complex)
What is reproduction?
Makes copies. Some sort of information storage (e.g. DNA/RNA)
What stimuli does life respond to?
Growth
Metabolism
Adapt/evolve
What does growth do with materials?
uses outside materials which are incorporated into the organism
What is polymerisation?
Joining together of smaller molecules to larger chain-like molecules (organic matter)
What is crystallisation?
Packing of atoms or molecules in repeated patterns (inorganic matter)
What can organisms contain which is crystalline?
crystalline structures - bones and shells
What does polymerisation and crystallisation do with energy?
Polymerisation absorbs energy
Crystallisation releases energy
What is metabolism?
Chemical reaction(s) which an organism gets energy from
What is aerobic metabolism?
with oxygen
What is anaerobic metabolism?
oxygen free
What do autotrophs do with carbon?
fix it (store)
What are 2 examples of autotrophs?
Photoautotrophs (photosynthesis)
Chemoautotrophs (Chemosynthesis)
What do heterotrophs do with carbon?
respire pre existing organic carbon
What do primary producers do?
convert energy and inorganic compounds into biomass
What are the 3 steps of primary production?
1- autotroph produces organic matter
2- Some OM used as fuel for meta and resp
3- store OM carbon compound for future
What is the by-product of step 1 of primary production? (OM produced)
gross production
What is the name for the biomass leftover from step 3 of primary production?
Net production
What is thermodynamics? (metabolism in earth system)
energy taken from the environment
Why cant the biosphere sustain itself indefinelty?
There are losses down the food chain as energy is lost via processes like heating and respiration
What is the first law of thermodynamics?
energy is not created or destroyed, it only changes forms
What is the second law of thermodynamics?
he sum of the entropies of a system
and its surroundings must always increase (disorder always increasing)
What is entropy?
measure of randomness
What is Gibbs free energy?
the amount of energy left over after a chemical reaction has taken place
Why is Gibbs free energy used?
how energy of system changes from one state to another
How can life inhabit rocks?
being on, under or in
What are some examples of how life make rocks (minerals)?
Carbonates (calcite)
Sulfides (pyrite)
Metal oxides (magnetite)
Silicates (diatoms)
Phosphates (teeth, bones)
What are the 3 domains for the hierarchy of life?
Bacteria
Archaea
Eukarya
What are the characteristics of prokaryotes?
No nucleus
What are the characteristics of eukaryotes?
membrane bound to nucleus (many organelles)
May be multicellular
What are some examples of Eukarya?
plants
animals
fungi
protists
What are some examples of prokaryotes?
Bacteria
Archaea
What is the Linnaean system of taxonomic classification?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What multiple species concepts are there?
Biological
Phylogenetic
Morphological
What is the biological multiple species concept?
reproductive isolation/ no successful breeding
What are the cons of biological multiple species concept?
Only really makes sense for sexual reproduction
Anthropogenic disturbance
What is the phylogenetic concept of multiple species?
accruing enough genetic distance
What is the morphological multiple species concept?
Apperance
What are the cons of the morphological multiple species concept?
Cryptic species (genetic and behavioural
differences
What is abiogenesis?
making living organisms from non-living matter
What does abiogenesis require?
Requires lots of steps, each increasing the organisation/complexity of the system, but with countless failures
What did organic molecules originally have to be synthesised from?
earths earths chemical ingredients
What are some of the most vital elements found in abundance on earths surface?
H, C, O, N, P, S
What formed from the vital elements for life?
monomers- i.e. amino acids
What are amino acids the building block for?
Polymers- more complex organic molecules
Who did the primordial soup experiment?
Miller-Urey
What was the point of the primordial soup experiment?
to produce amino acids from the vital life elements using gas and an energy spark
What will happens to amino acids monomers at high concentrations?
polymerise (form DNA and RNA)
How can polymerised amino acids be formed in the lab?
heating, evaporating, and concentrating an amino-acid-bearing solution
What happens to artificial polymers if left in water?
will dilute as need a cell
What happens when you agitate the artificial polymers?
will clump and make microspheres
What are microspheres like?
crude delicate cell membrane
not robust
What is the black smoker hypothesis?
Hydrothermal fluids have vital elements
Hydrothermal vent provide heat
Make monomers
Evapo not possible for polymers but maybe on clay mineral surface
What is Panspermia?
organic molecules may have arrived from some part of the solar system or even the galaxy beyond the solar system
What is LUCA?
Last Universal Common Ancestor
What was first life more likely to be prokaryotic or eukaryotic?
Prokaryotic - archaea
Why is archaea likely to have been first life?
most are extremophiles (tolerate temp, salinity and acid)
Why is it hard to show archaea as early life?
no direct archaea fossils from Precambrian
How can stromatolites be used for evidence of early earth life?
3.5 Ga
layered, domed
Macrofossil constructed by photosynthetic cyanobacteria
How can graphite in Isua greenstone be evidence of early earth life?
graphite layers in 3.8 Ga isua greenstone enriched in C12
Potentially biogenic
When did eukaryotes form from prokaryotes?
1.4 Ga
What do eukaryotes require?
oxygen
What was the reason for eukaryote rise?
sufficient molecular oxygen (toxic by product of photosynthesis)
What is the first animal on earth thought to be?
sponge (evidence= sponge biomarkers)
Why are sponges thought to be one of first animals?
can build up from cell level due to adhesive joining due to collagen
What are some earth biosphere milestones?
Life origin
Photosynthesis origin
Multicellularity
Base Cambrian - Treptichnus pedum (burrow trace fossil)
Life on land - Devonian
Mineralising plankton- Mesozoic
What was needed by first plant life on land which formed in the Devonian?
Structural support
Internal aquatic environment plus plumbing
Gas exchange mechanism
Moist reproductive environment
What does evolution by natural selection act on?
individuals
What does adaptation act on?
only on a population over generations not individuals
What is the end result of evolution/ adaptation?
Speciation
What are the 2 types of speciation?
Allopatric
Sympatric
What is sympatric speciation?
reproductive isolation without geographic barrier
What is allopatric speciation?
results from geographic barrier
What is epigenetics?
How DNA interacts with multitude smaller molecules in cells activate and deactivate genes
What can epigenetics do to transcription of specific genes?
Boost or interfere
How do epigenetics interfere with gene transcription?
DNA coiled tighter making it inaccessible essentially muting it
