Energy and Matter Exchange in the Biosphere Flashcards
1
Q
What is ecology?
A
The study of the relationships between living organisms and their environments
2
Q
What is biodiversity?
A
refers to the number of species in an ecosystem
3
Q
Is it more beneficial for an ecosystem to have higher or lower biodiversity?
A
Higher
4
Q
Can species exist in isolation?
A
No, they all depend on interaction in some way
5
Q
What is a system in biology?
A
an object or group of objects a scientist studies
6
Q
What are the three types of systems?
A
- open
- closed
- isolated
7
Q
What is an open system?
A
both energy and matter can enter or leave
8
Q
What is a closed system?
A
only energy can enter or leave
9
Q
What is an isolated system?
A
Neither energy or matter can enter or leave
10
Q
What kind of system is Earth?
A
A closed system
11
Q
What is the name of Earth’s system?
A
The biosphere
12
Q
What do all organisms need?
A
energy
13
Q
What do organisms use energy for?
A
They use it to grow, maintain body processes, and reproduce
14
Q
What are autotrophs?
A
Producers; self-feeders; organisms that are able to use energy to produce food for themselves
15
Q
What are the two processes autotrophs may use?
A
Photosynthesis and chemosynthesis
16
Q
What is the formua for photosynthesis?
A
6CO_2 + 6H_2O + light energy = c_6H_12O_6 + 6O_2
17
Q
What is the formula for Chemosynthesis?
A
CO_2 + O_2 + H_2S = CH_2O + 4S + 3H_2O
18
Q
What is photosynthesis?
A
Most autotrophs use it; uses light energy from the sun to create food
19
Q
How much of the sun energy can be used by organisms?
A
Of the sun energy that reaches Earth:
- 30% is reflected into space (depends on albedo)
- 19-20% is absorbed by gases
- 50% is absorbed by the surface
- less than 1% is absorbed by photosynthesizers
20
Q
What is chemosynthesis?
A
Autotrophs in light-free environments use chemosynthesis to produce organic molecules
21
Q
How does chemosynthesis work?
A
Ex. Methanopyrus chandler in deep-sea vents:
- split hydrogen sulfide molecules from the vents
- capture energy stores in the chemical bonds
- produces sulfuric acid
22
Q
What is a heterotroph?
A
Consumer; other-feeder; an organism that is incapaable of making its own food and gains energy by eating other oganisms.
23
Q
What is cellular respiration?
A
The process where organisms convert chemical energy in glucose to create ATP (organism’s main fuel source)
(producers also use it to break down the glucose they produce)
24
Q
What is the formula for cellular respiration?
A
C_6H_12O_6 + 6O_2 = 6CO_2 + 6H_2O + ATP
25
What are primary consumers?
Herbivores; primarily eaters of plants and other producers
26
What are secondary consumers?
omnivores or carnivores; mainly ear herbivores
27
What are tertiary consumers?
Usually true carnivores; organisms that eat secondary consumers
28
What are decomposers/detritivores?
Eat dead/decaying organisms (breaking them into simpler nutrients/matter); final group of consumers
29
What type of consumers are humans?
Tertiary
30
What is a food chain?
shows the linear pathways through which food/energy is transferred in an ecosystem
31
What is a food web?
Model of food/energy transfer in an ecosystem taht shows the connection among food chains (more accurate)
32
What are keystone species?
Have an especially large impact on their habitat/ecosystem
33
What is a trophic cascade?
an ecological phenomenon triggered by the addition or removal of a top predator in an ecosystem
34
What do trophic cascades cause?
Changes in populations (dramatic shifts in ecosystem structure and nutrient cycling)
35
What is a trophic level?
a level through which energy and matter are transferred
36
What is the first trophic level?
Always producers; provides all chemical energy needed to fuel other levels
37
What do the trophic levels above the first one consist of?
consumers
38
Which trophic level do decomposers belong in?
They may feed at any of the trophic levels
39
What is the first law of thermodynamics?
energy cannot be created nor destroyed, only changes forms (as energy is transferred through each trophic level some are lost, but not destroyed, just converted into an unusable form)
40
What is the second law of thermodynamics?
Any energy change results in waste energy (During energy transfer through the trophic levels, there is always waste energy through things such as heat and animal waste)
41
Why must organisms at the top of the chain consume more?
Energy is lost at each transfer, so less is available to higher levels
42
What is the Rule of 10?
ecologists assume that only 10% of the energy at one trophic level is transferred to the next
43
What does the Rule of 10 limit?
The number of trophic levels and the number of organisms at each level (less available energy as you go up)
44
What is are ecological pyramids?
They provide a visual representation of the relationships among trophic levels in a given ecosystem
45
What are the three types of ecological pyramids?
- pyramid of numbers
- pyramid of biomass
- pyramid of energy
46
What is a Pyramid of Numbers?
Shows the total number of organisms (doesn't take an upright shape)
47
What is a Pyramid of Biomass?
Shows the dry mass of living/once living organisms per unit area (in g/m^2)
Is always pyramid shaped/upright
48
What is a Pyramid of Energy?
Shows the energy contained at each tropic level (in J or KJ)
Is always pyramid shaped/upright
49
What are biochemical cycles?
The route that chemical nutrients take through the biotic and abiotic components of the Earth's biosphere
50
What are the different types of biochemical cycles?
- water/ hydrological cycle
- carbon and oxygen cycle
- nitrogen cycle
- phosphorus cycle
- sulfur cycle
51
What makes water special as a solvent?
- made up of two hydrogen and one oxygen
- since hydrogen end is positive and oxygen is negative it is polar
- hydrogen molecules of one water moecule has attraction to oxygen of another (hydrogen bonding)
- hydrogen bonds and polarity allows water to dissolve many substances (making it a universal solvent)
52
What makes water special with it melting/boiling point?
- has relatively high melting and boiling point
- also the only substance on planet found naturally in gas, liquid, solid states
- expands when frozen due to hydrogen bonds holding water in an open crystal structure, which breaks down as it melts so loosened molecules pack more closely and increase density
- it is most dense at 4 degrees celsius
53
What makes water special with its heat capacity?
- water has a high heat capacity (measure of amount of heat a substance can absorb/release for a given change in temp; requires mor eneergy to change temp)
- heat capacity of water allows surface currents to distribute heat from warmer regions to higher lattitudes
- since water vapour is a green house gas, it traps and transfers heat in a similar way
54
What makes water special with cohesion/adhesion?
- its hydrogen and polarity also allows it to have both high cohesion (attraction of water molecules to each other) and adhesion (attraction of water molecules to molecules of another substance)
- cohesion allows organic debris to stay on surface water to provide nutrients to aquatic organisms
- adhesion allows upward pull of water from the ground against gravity
55
What is the hydrological cycle?
- water cycle; connects ecosystems even seperated by distance
- 97% of water in biosphere is liquid and 86% of evaporation occurs over oceans
56
What steps do the hydrological cycle consist of?
- precipitation
- infiltration
- snow melt and run off
- evaporation
- evaptranspiration
- condensation
57
What is the carbon cycle?
Shows the interrelation between cellular respiration and photosynthesis
58
What are nutrient reservoirs?
- places where substances are temporarily stored in at each step in a biogeochemical cycle
59
What is rapid cycling?
Substances cycle quickly through nutrient reservirs (ex. carbon moving from producer to consumer to decomposer back to atmosphere)
60
What is slow cycling?
Substances accumulate and are stored for long periods of time in nutrient reservoirs (ex. carbon in fossil fuel deposits)
61
How are the carbon and water cycle related?
- oceans are an effective carbon sink (about 1/4 of the excess CO2 from humans absorbed)
- when CO2 and water combine they produce carbonic acid
- oceans are acidifying slowly
62
Why is nitrogen important?
- key chemical in ecosystems (component of amino acids/proteins found in organisms and the genetic material DNA found in cells)
- 78% of atmosphere is nitrogen but it must be put through a series of transformations to be available to plants (way into food web)
63
What is nitrogen fixation?
Process in which atmospheric nitrogen is converted into ammonium and nitrates, thus making it available to be used by living organisms
64
What are the two ways Nitrogen fixation can occur?
- legumes
- lightning
65
How can nitrogen fixation occur by legumes?
- lumpy nodules of legume plants (ex. clover, peanuts, beans,etc) have bacteria that do nitrogen fixation
- mutually beneficial relationship provides plants with ammonium and bacteria with sugars produced by photosynthesis
66
How can nitrogen fixation occur by lightning?
When lightning strikes nitrogen gas is combined with water to form ammonium and nitrates
67
What is ammonification?
Process where atmospheric nitrogen is converted to ammonium by decomposers breaking down organic matter (nitrifying bacteria convert this ammonium into nitrite, then into nitrate which plants can use)
68
What is denitrification?
Denitrifying bacteria complete the cycle by converitng nitrite/nitrate back into nitrogen gas
69
what are agricultural effects on the environment?
- natural vegetation decomposes and returns nutrients to the soil so uncultivated/virgin soil has lots of accumulated nutrients
- once vegetation is cleareed crops can grow on the nutrient reserves for about 1-10 years as nutrient levels are depleted with every harvest
- leachate of nutrients also increases
- nutrients must be replaced by fertilizer or crop rotations (today there is more added nitrogen than all nitrogen-fixing bacteria combined)
70
Why is sulfur important?
- all organisms need sulfur as a part of proteins and vitamins
71
What different ways are sulfur used in the environment/
- plants and alge use sulfur as sulfate, which dissolves in water
- sulfur is released into the air as sulfur dioxide through volcanic acitivity, geologic uplift, burning/mining of fossil fuels
- sulfates returned to Earth through acid precipitation
72
How do bacteria help plants use sulfur?
- sulfate reducers convert sulfates to sulfides
- sulfur oxidizers convert sulfides into elemental sulfur and sulfate
73
How is acid deposition produced?
- burning of fossil fuels releases sulfur and nitrogen into the atmosphere as sulfur dioxide and nitrous oxides
- these react with water vapour and form sulfuric and nitrous acids
- acidifies lakes, rivers, soils through precipiatation/deposition
74
Why is phosphorus important?
- key component of DNA, ATP, phospholipids, bones and teeth
- autotrophs uses it as phosphate, which dissolve in water
- special from other elements as it doesn't cycle through the atmosphere
75
What effects algal blooms?
- growth of algae in lakes limited by amount of nutrients
- more nutrients introduced (sewage, industrial waste, fertilizers) cause algae numbers to swell
76
What are the effects of algal blooms?
- decomposers break down algae, use up oxygen, kill fish and other aquatic life
- organic material accumulates on bottom, increases aquatic plants
77
What is sustainability?
The ability to continue indefinitely
78
What are the three aspects for an ecosystem to be sustainable?
- sufficient sunlight falls on the ecosystem
- nutrients are recycled
- toxic waste products don't accumulate
79
What is homeostasis?
The aspects are balanced, creating sustainability
80
What gives ecosystems the potential to be sustainable for long periods of time?
The complementary nature of photosynthesis and cellular respiration
81
What is dynamic equilibrium?
Condition in which small fluctuations/changes are continuously occurring but balance is still maintained
82
What is the Gaia Hypothesis?
- James Lovelock proposed it based on the idea of dynamic equilibrium
- states that Earth is a loving body and all organisms and their inorganic surroundings on earth form a single, self evolving, self regulating, self sustaining complex system
83
What does evolving, regulating, and sustaining mean according to the Gaia Hypothesis?
Evolve- change and become more efficient
Regulate- Able to monitor, control, and adjust itself
Sustain- maintain current life indefinitely
84
What is global warming?
A gradual increase in the average temperature of Earth's atmosphere and oceans
85
What are the different levels of a lake?:
- Littoral
- Limnetic Zone
- Profundal Zone
86
What does the Littoral Zone have?
an upper zone of a lake that connects with the land; organisms that need to be rooted and organisms that consume them are present in this layer
- have phytoplankton
87
What does the Limnetic Zone have?
this is the upper layer of the water which is open to solar radiation which allows photosynthesis and also warms the water; organisms that photosynthesize and
absorb nutrients from the water (ex.algae) live here, as well as the organisms which consume them
- have phytoplankon
88
What does the Profundal Zone have?
this is the deepest layer of the lake which has little access to radiant energy, making it low in nutrients and temperature; bottom dwellers reside here
89
What is the Bethnic Zone?
Bottom of the Lake
