Biosphere: (Biosphere Intro)

Question 1

Stromatolites:

Answer 1

•(scientists think) in the past, the atmosphere lacked free oxygen (anoxic) and bacteria grew, forming thick mounds in the shallow seas, lagoons, and lakes.
•Cyanobacteria use sunlight, H2O, and CO2 and produce O2 as a byproduct.
•as the micro-organisms died, the cells piled up, trapping or precipitating sediments and eventually forming sedimentary rocks = stromatolites.

Question 2

Biosphere:

Answer 2

•biosphere: all of the areas on Earth that are inhabited by and that support life. Made up of 3 continuously interacting main components:
-1. Hydrosphere: the water portion of Earth.
-2. Atmosphere: the gaseous part of Earth. Concentrated mainly within 10km above the Earths surface, but also extending hundreds of kilometres higher.
-3. Geosphere: the solid, mainly rocky part of Earth (also called the lithosphere).

Question 3

Energy flows:

Answer 3

•enters from the sun or chemicals.
•stored via photosynthesis/chemosynthesis.
•used via cellular respiration.
•lost as heat.

Question 4

Chemosynthesis:

Answer 4

•deep sea vent ecosystems.
•no light present for photosynthetic producers.
•bacteria provide nutrients for the tube worms through chemosynthesis.
•microbes split H2S from the sea vent and capture the energy from splitting molecules (energy comes from chemicals not the sun).

Question 5

Populations:

Answer 5

A group of individuals of the same species occupying the same area at a given time.

Question 6

Community:

Answer 6

More than one populations of organisms living in a given area.

Question 7

Ecosystem:

Answer 7

-A community and its abiotic and biotic components and interactions.
-organism—>populations—>community—>ecosystem.

Question 8

Biodiversity:

Answer 8

•biological diversity: the number of species in an ecosystem.
•each organism in an ecosystem is connected to all the other organisms.
•if there is a reduction/removal in one part of the ecosystem it can cause a “domino effect”.

Question 9

Predators and prey:

Answer 9

•food chain: a step-by-step sequence linking organisms that feed on each other, starting with a food source such as plants (procucers) and continuing with animals and other living things that feed on the plants and on each other (consumers).
•when a species acts as a predator, it keeps the population of its prey in check.
•when a species acts as a prey, it provides an important food source.

Question 10

Factors that influence an ecosystem:

Answer 10

•biotic factors: living components of the biosphere.
-ex) plants, animals, microbes, parasites, etc.
•abiotic factors: non-living components of the biosphere.
-ex) rocks, minerals, and physical factors (sunlight, temperature, weather, etc).

Question 11

Biosphere in balance:

Answer 11

•to live, an organism must maintain its internal conditions within certain limits in spite of changing external conditions.
•maintaining a state of balance = equilibrium = homeostasis.
•dynamic equilibrium: a system in a steady state where the rate of loss is equal to the rate of gain.

Question 12

Gaia hypothesis:

Answer 12

•Gaia hypothesis: “biosphere acts like an organism that regulates itself, maintaining environmental conditions within certain limits”.
•interaction between living and non-living to form a synergistic self-regulating system.
•the biosphere needs a constant input of energy, and the cycling of nutrients to maintain its internal balance.