Unit 3: Ecosystems Flashcards
1
Q
3.1: Energy and Matter
A
2
Q
Metabolism (definition)
A
all of the chemical processes that build up or break down materials in an organism’s body
3
Q
Law of Conservation of Energy
A
energy cannot be created/destroyed
- form of energy may change, but amount doesn’t
4
Q
Is matter conserved in the same way
A
yes
5
Q
Ecosystem (definition)
A
complex web of interconnected biotic and abiotic components
6
Q
Are all species affected by a/biotic factors
A
yes
7
Q
Feeding relationships (definition)
A
major component of the structure/dynamics of an ecosystem
8
Q
What do food chains and food webs model
A
the complex structure of an ecosystem and to better understand how energy is transferred between organisms
9
Q
What is the simplest way to look at the transfer of food energy in an ecosytem
A
through a food chain
10
Q
Food chain (definition)
A
sequence that links species by their feeding relationships
11
Q
Herbivores (definition)
A
organisms that only eat plants
12
Q
Carnivores (definition)
A
only eat animals
13
Q
Omnivores (definition)
A
organisms that eat both plants and animals
14
Q
Detritivores (definition)
A
organisms that eat detritus
15
Q
Detritus
A
dead organic matter
16
Q
Decomposers (definition)
A
organisms that break down organic matter into simpler compounds
17
Q
Function of decomposers in an ecosystem
A
important to ecosystem stability - return vital nutrients back into environment for other organisms to use
18
Q
Trophic levels (definition)
A
levels of nourishment in a food chain
19
Q
What occupies the first trophic level
A
producer
20
Q
What occupies the second trophic level
A
usually a herbivore
21
Q
What occupies the third/fourth levels
A
secondary/tertiary consumers - omnivores/carnivores
22
Q
How does energy flow in a food chain
A
up, from bottom trophic level to top
23
Q
Why are food chains limited in length
A
because energy is lost as heat at each trophic level
24
Q
What do organisms use the remaining energy to do
A
carry out life functions - cellular respiration, growth
25
Can an organism be part of many different food chains
yes
26
Food web (definition)
models the complex network of feeding relationships between trophic levels within an ecosystem
27
What does the stability of any food web depend
the presence of producers - form the base of the food web
28
What does a food web show
how the different food chains within an ecosystem are related and how energy/matter are transferred between organisms/trophic levels
29
Where do most ecosystems get their energy from
the sun
30
Why do higher trophic levels receive less overall energy than the ones below them
because some energy is given off as heat that escapes into the environment
31
4 ways the energy an organism acquires is transformed
1. metabolic processes
2. new biomass
3. released as heat
3. excreted as waste
32
Metabolic processes (definition)
provide energy for movement/maintenance of the organisms
33
Biomass (definition)
growth of the organism
34
Pyramid models (definition)
show patterns of energy/matter distribution at the ecosystem level
35
What are pyramid models useful for showing
productivity of an ecosystem and can illustrate an ecosystem's distribution of:
1. energy
2. biomass
3. number of organisms
36
Productivity (definition)
percentage of energy entering the ecosystem that is incorporated into biomass at a particular trophic level
37
What do pyramid models allow scientists to compare
distribution of energy/biomass/number of organisms between trophic levels within the same ecosystem or a different one
38
Trophic efficiency (definition)
percentage of energy transferred from one trophic level to the next
39
Energy pyramid (definition)
models the transfer of energy beginning with producers and working up the food chain to the top-level consumer
40
Which trophic level has the largest base in a typical energy pyramid
the producers (first trophic level)
41
Does more trophic levels correspond to greater loss of energy from the ecosystem
yes
42
In an idealized energy pyramid, what percentage of energy is transferred to the next level
10%
43
What is the typical trophic efficiency range
5 - 20%
44
What percentage of sunlight do plants convert to usable energy
1%
45
Why do plants convert so little sunlight --> energy (3)
1. not all sunlight hits the leaves of a plant
2. not all wavelengths of light are absorbed
3. photosynthesis requires large quantities of energy
46
3 things consumed energy is used for in organisms
1. new cells
2. excreted
3. homeostasis + metabolism
47
Does energy efficiency vary between organisms
yes
48
What percentage of energy is used to maintain metabolism in warm blooded animals
98 percent
49
What do cold blooded animals use their excess energy for (2)
fuel other activities like growth/reproduction
50
Biomass pyramid (definition)
compares the biomass at different trophic levels within an ecosystem
51
Biomass (definition)
total dry mass / unit of area
52
Does biomass include dead organic matter
yes
53
How are dead bodies cycled back into the biomass pyramid
by decomposers such as fungi and earthworms
54
Does the amount of biomass decrease in a biomass pyramid as you move up the trophic levels
yes
55
What does the percentage of biomass transferred to the next trophic level depend on
1) types of organisms present in the ecosystem
2) level of consumption
56
Pyramid of numbers (definition)
shows how many individual organisms are present at each trophic level in an ecosystem
57
Does a pyramid of numbers always have a larger base
no
58
Biomagnification
process through which chemicals enter the food chain and build up in the bodies of organisms
59
3.2: Cycling of Matter
60
Is the Earth an open or closed system in terms of energy
open system
61
Is the Earth an open or closed system in terms of matter
closed a system - small amount of matter is lost into space from atmosphere
62
What drives the cycling of matter in Earth's spheres
energy from the sun
63
Study water, oxygen, nitrogen, phosphorus, and carbon cycles
64
Which sphere is the longest-term carbon reservoir
geosphere - carbon moves between hydro-, atmo-, and biosphere in few hundred years
65
What 3 processes cycle carbon between systems in the biosphere
1. photosynthesis
2. cellular respiration
3. decomposition
66
What gases do the ocean and atmosphere exchange
carbon dioxide
67
Where does carbon move on land
towards longer term reservoirs (e.g. wood) bc respiration + photosynthesis balance each other out
68
Where does human activity move carbon
into the atmosphere from long-term storage in bio/geosphere
69
How does human activity disrupt the cycling of carbon, phosphorus, and nitrogen
by adding synthetic chemicals and materials to Earth which cannot be integrated into normal ecosystem functions
70
Where does air pollution come from
waste products produced by burning fossil fuels
71
Examples of fossil fuels (2) and what do they contain (3)
Gasoline and oil that contain carbon, nitrogen, and phosphorus
72
What does the burning of fossil fuels release (3)
carbon dioxide, methane, nitrous oxide, etc
73
Smog (definition)
type of air pollution caused by interaction of sunlight with pollutants produced by fossil fuel emissions
74
How is ozone (O3) produced
by the reaction of nitrogen dioxide in smog with oxygen
75
Where does ozone produced by smog tend to stay and why is that harmful
stays close to the ground, is harmful to human health + ecosystem functions
76
Where does natural ozone exist and what are its benefits
exists naturally in the upper atmosphere, acts as a shield protecting Earth's biosphere against harmful UV rays found in sunlight
77
What do carbon dioxide emissions lead to
increase in atmosphere CO2 - rate at which it enters is faster than the rate at which it is removed
78
2 examples of human activity leading to increased CO2 levels
1. combusting fossil fuels
2. clear cutting forests
79
Is CO2 a greenhouse gas
yes
80
Greenhouse gas (definition)
allows sunlight to pass through and provide energy for producers, ut keep infrared radiation (heat) from escaping
81
What is increasing atmospheric carbon dioxide linked to
increasing global temperature
82
2 examples of environmental effects of increased global temperature
1. species moving into new areas
2. shrinking polar ice caps
83
What type of fertilization production has increased over the last few decades
production through nitrogen fixation + phosphate mining
84
Fertilizers (definition)
used to enrich the soil and stimulate plant growth
85
What occurs when crops are overfertilized
rain causes excess nitrogen and phosphorus to run off --> nearby water bodies
86
What occurs if there is fertilizer runoff (2)
1. alters nutrient balance in water
2. algae bloom
87
Algae bloom (definition)
when aquatic producer (e.g. algae) growth is stimulated
88
Erosion (definition)
movement of rock, soil, and sand by wind and water
89
Where does eroded soil wash into
nearby waterways
90
How do humans contribute to soil erosion
most farming methods remove plants that hold soil in place (ex: plowing which loosens soil and removes plants holding it in place)
91
92
What does mining expose rock to
air and water to obtain minerals
