Chapter 11 Flashcards
biosphere
the part of the planet that contains all of it’s living organisms
geobiology
the study of the interactions between the biosphere and Earth’s physical environment
ecosystems
the organizational units of biological communities and their environments
autotrophs
organisms that make their own food
heterotrophs
feed directly or indirectly on producers
metabolism
all the processes organisms use to convert inputs into outputs
cyanobacteria
use photosynthesis to make carbohydrates
respiration
organisms release the energy stored in carbohydrates
biogeochemical cycle
the cycle where a chemical element or compound moves between the biological and environmental components of a system
microorganisms
single-celled organisms
wherever there is water, these are present
Three domains of life
bacteria
archaea
eukarya
what is the youngest domain of life?
eukarya
extremophiles
microorganisms that live in environments that would kill other organisms
acidophiles
microorganisms that live in acidic environments
thermophiles
microorganisms that live in extremely hot environments
what temperature range do thermophiles thrive in?
50 - 70 degrees celsius
examples of thermophile environments
hot springs
compost piles or landfills
halophiles
microorganisms that live in highly saline environments
anaerobes
microorganisms that live in environments completely devoid of oxygen
example of biogeochemical cycle
phosphorous
- cycle between water and microorganisms
- cycle between rocks in mountains to sediments in the ocean
mineral precipitation
indirectly - influencing the composition of the water around them
directly - in their cells as a result of their metabolism
mineral dissolution
elements like sulfur and nitrogen can be readily available from natural waters in dissolved form
chemoautotrophs
autotrophs that derive their energy from the chemicals produced when minerals dissolve
biogeochemical cycle of pyrite
- iron and sulfur precipitate as pyrite
- when layers of sediments are deposited, pyrite is buried
- returns to the surface through plate tectonics
- rocks start to weather and the iron and sulfur are dissolved back into the water
microbial mats
layered microbial communities
microbial mat structure
top - oxygen-producing cyanobacteria that uses photosynthesis - aerobic
second - anaerobic heterotrophs that derive their food from the organic matter produced in the above layer
stromatolites
rocks with distinctive thin layers
what forms stromatolites?
many microbial mats
how old is the Earth?
4.5 billion years old
what does evolution say about microorganisms?
they evolved from a universal ancestor with genetic information
prebiotic soup hypothesis
- early planetary materials might contain amino acids
- amino acids could have formed on a planet without oxygen
when do most geobiologists think life on Earth began?
3.5 million years ago
chemofossils
chemical remains of organic compounds made by ancient microorganisms
when did photosynthesis become an important metabolic process?
2.7 billion years ago
evolutionary radiation
rapid development of new types of organisms from a common ancestor
Cambrian explosion
- 542 million years ago a radiation of animals during the Cambrian era
- every major animal group that exists on Earth today appeared in less than 10 million years
hypotheses for the cause of the Cambrian explosion
- multicellularity opened up new evolutionary possibilities
- development of shells and skeletons triggered diversification
when did dinosaurs go extinct?
65 million years ago
when did the Paleocene-Eocene mass extinction occur?
55 million years ago
what was the Paleocene-Eocene mass extinction?
the oceans released an enormous amount of methane (greenhouse gas) into the atmosphere
how did the Paleocene-Eocene mass extinction occur?
the temperatures on Earth were rising which cause the frozen methane on the sea floor to turn into a gas and bubbled at the surface of the ocean
what was the mother of all extinctions?
the mass extinction at the end of the Permian Period and the Paleozoic era
what are the essential ingredients for life?
water and carbon
where are we looking for life and why?
we are looking on Mars because water is present in ice form
habitable zone
the distance from a star at which water is stable as a liquid
