BIOL 111 - Post Midterm 2 Flashcards

(114 cards)

1
Q

Why can bryophytes only transport over short distances?

A

They do not have lignin or vascular tissues

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2
Q

What limits the size of bryophytes?

A

Due to the lack of specialized exchange surfaces or transport systems, body size is limited by diffusion.

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3
Q

What are the three transport routes in plants?

A

Apoplastic route - Continuum of cell walls and extracellular spaces.

Symplastic route - Continuum of cytoplasm connected to plasmodesmata

Transmembrane route - Goes through the cytoskeleton as well as cell wall.

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4
Q

What does the plasmodesmata allow?

A

Cell-to-cell transport without crossing a permeability barrier.

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5
Q

What type of barrier is the plasma membrane? (Permeability)

A

Selectively permeable

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6
Q

Symplast vs apoplast

A

The apoplast is the continuum of cell walls and extra cellular spaces
Symplast is the continuum of cytosine connected by plasmodesmata

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7
Q

What facilitates water movement across membranes (osmosis)?

A

Aquaporins

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8
Q

What is bulk flow? What is dependent on bulk flow?

A

Movement in response to pressure gradients.

Long distance transport depends on bulk flow.

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9
Q

What does the bulk flow in xylem depend on?

A

Depends on transpiration.
As water is lost from leaves the pressure gradient is lower higher in the tree causing water to move up the xylem.

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10
Q

Cohesion-Tension hypothesis steps

A

Evaporation at leaf surface produces negative pressure
Cohesion and adhesion in xylem pull water upward to replace water lost by transpiration

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11
Q

What regulates water loss and how?

A

Stomata regulate water loss by opening in response to light and CO2 and closing in response to drought stress.

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12
Q

Proton pumps in relation to stomata

A

Proton pumps are active when stomata are open - Passive ion diffusion ,inward osmosis, cell turgor increases.
Inactive when stomata are closed - Indirect active ion pumping, outward osmosis, cell turgor decreases.

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13
Q

What relative atmospheric CO2 would indicate high stomata density?

A

Low atmospheric CO2

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14
Q

What relative atmospheric CO2 would indicate low stomata density?

A

High atmospheric CO2

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15
Q

What can be used as an indicator of past CO2 concentrations?

A

Stomatal density in fossilized leaves.

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16
Q

Symplastic vs apoplastic loading

A

Symplastic loading is passive - Relatively low sucrose concentration in phloem sap

Apoplastic loading is active. - High sucrose concentration in phloem sap

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17
Q

What is meant by source to sink?

A

Refers to bulk flow in phloem - sucrose moves from source to sink

At source there is a high sucrose concentration in phloem which causes water to diffuse in from the xylem.

At sink there is low sucrose concentration resulting in water being pulled back into the xylem.

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18
Q

Biome

A

Ecosystems with similar structure structure in a large region

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19
Q

Ecosystem

A

All of the biotic and abiotic factors in a specific area. Total biotic community and its abiotic environment.

Includes all of the living organisms and the physical environmental factors in an area.

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20
Q

Community

A

Individuals of multiple species in a single area.

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21
Q

Population

A

Individuals of a single species in a specific area.

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22
Q

What are the five trophic levels?

A

Producers -> Primary consumers -> Secondary consumers -> Tertiary consumers -> Detritivores

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23
Q

What do autotrophs do generally?

A

Producers that convert solar energy and inorganic nutrients into organic matter.

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24
Q

What is the role of detritivores?

A

Consume dead organic matter and release inorganic nutrients back into the environment.

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25
What is climate?
A long term average weather pattern including mean annual temp, mean annual precipitation and seasonality.
26
Where would you find arid climates?
Dry air returns to the surface near 30 degrees latitude, creating arid climates.
27
Where does the most solar heating occur?
Around the equator. Hot tropical air absorbs moisture and rises. Near the top of the troposphere water vapour condenses and falls back to the surface.
28
Where are "moist" climates found?
60 degrees latitude.
29
What are tropical air cells called?
Hadley cells
30
What creates alternating wet and dry climate zones?
Atmospheric cells.
31
Where do other air cells form?
Temperate and polar zones
32
What causes surface winds?
Earth's rotation
33
What direction do tropical trade winds blow?
Easterly - east to west
34
What direction do temperate winds blow?
Westerly - west to east
35
Where are coastal temperate rainforests found in relation to winds?
Found where westerly winds bring high rainfall to the west coast of a continent.
36
What causes seasonal variation?
The tilt of the earths axis.
37
What is the effect of the June solstice versus the December solstice for the northern hemisphere?
During the June solstice the Northern Hemisphere tilts towards the sun and the opposite for the December solstice.
38
What is the rain shadow effect?
Cool air flows inland from the water, as the air encounters the mountains and flows upward it cools at higher altitudes and releases water as rain and snow. Less moisture is left in the air after the mountain creating a drier environment on the other side. Coastal rain forest -> Subalpine meadow -> Grassland
39
What is the effect of altitude on temperature in the mountains?
Temp changes around 6 degrees for every 1000m of altitude. Similar to moving poleward about 1400km
40
What drives the earths water cycle
Solar energy?
41
What drives surface currents in the oceans?
Trade winds and westerlies.
42
Which way do gyres rotate?
Clockwise in northern hemisphere and counter in the southern hemisphere.
43
Photic zone and Aphotic zone
Vertical zones Photic zone is on the surface where there is enough light to support photosynthesis. Maximum depth of 150-200 metres. Aphotic zone is dark zone below the photic zone.
44
Pelagic and benthic zones
Benthic is the sea floor Pelagic zone is the water column above the sea floor.
45
Coastal and oceanic zone
Horizontal zones Coastal zone is the area above the continental shelf. Oceanic zone is everything is the ocean past the edge of the continental shelf.
46
Conifers
Cone bearing trees, most with needle-like leaves.
47
What type of trees produce flowers and fruits?
Broad-leaf trees are typically flowering
48
What differences can be seen between broadleaf trees in the tropics versus more season climates?
Broadleaf trees in the tropics are typically evergreen as opposed to deciduous.
49
Are most conifers evergreen or deciduous?
Evergreen with a few exceptions
50
What do forests require?
High precipitation and warm temps during growing season.
51
What limits tree growth?
Water availability and length of the growing season. Fire also suppresses tree growth and promotes the spread of grasses.
52
Attributes of tropical forests
Tropical rain forest - High temp and precipitation all year. Broad-leaved evergreens. Tropical dry forest - High temp, wet and dry seasons. Broad-leaved deciduous trees.
53
Attributes of tropical savannas
High temp, wet/dry seasons, frequent fires. Mixed trees and grasses.
54
Attributes of deserts
Low precipitation year round, hot or cold, sparse vegetation. Xerophytes (cactus)
55
Temperate shrubland
Warm temperate/subtropical climate. Winter rain/summer drought Frequent fires Hard-leaved shrubs Cold winters/warm summers
56
Temperate grasslands
Large temp range Semi-arid Frequent fires Grasses Cold winters/warm summers
57
Temperate broadleaf forests
Cool temperate High precipitation Broad-leaved evergreen or deciduous trees.
58
North American temperate rainforests
Cool temperate climate Very high precipitation Needle-leaved evergreen trees
59
Boreal forests
Cold winter Low precipitation Needle-leaved evergreen trees.
60
Polar ecosystems
Tundra - Cold and dry all year, shrubs and grasses. Polar ice - Very cold and dry, no vascular plants.
61
What accounts for most of the photosynthesis in aquatic ecosystems?
Single-celled phytoplankton. Large seaweed and aquatic plants have high productivity in some local environments.
62
What are the three clades of unicellular eukaryotic algae that are the most important ocean producers?
Dinoflagellate, Diatom, Haptophyte.
63
What clade of algae would you expect to find in high nutrient vs. low nutrient areas?
Mostly large diatoms in high nutrient areas. Cyanobacteria and small flagellates in low nutrient areas
64
What characterizes freshwater ecosystems?
Flow regimes - flowing water characterizes rivers and still water characterizes lakes and ponds.
65
What is included in freshwater wetlands?
Swamps, marshes, and seasonally flooded grasslands.
66
What are estuaries?
Environments where rivers flow into the sea.
67
Where are kelp forests found?
Temperate oceans
68
Where are some of the most productive and diverse marine ecosystems found?
Shallow coastal waters
69
Where are coral reefs found?
Tropical oceans
70
Are corals animals?
Yes! They have symbiotic algae living in their tissues.
71
Where does life in the aphotic zone get its nutrients?
Organic material that is transported down from the photic zone
72
Deep sea hydrothermal vent producers?
Chemosynthetic bacteria
73
What is an ecological niche?
The range of environmental resources and conditions a species requires Describes the role an organism plays in a community. Example: The range of water temp a species of salmon can tolerate.
74
Habitat
The place where a species is found
75
There is a population of 10 lizards, 2 lizards are born and 1 dies, what is the populations growth rate
r = b - d b = 2/10 = 0.2 d = 1/10 = 0.1 r = 0.2 - 0.1 = 0.1 r = 10%
76
When might a population grow exponentially?
When it first colonizes a new area or a change in environmental factors. Example: Elephant population grew exponentially after protection from hunting.
77
What is a carrying capacity?
The maximum number that a population can be sustained at. Depends on the habitats resources.
78
What are some examples of density dependent population limiters?
Limited resources, predators, disease.
79
What are some examples of density independent population limiters?
Fires, floods, extreme weather.
80
Which factors; independent or dependent regulate a population?
Dependent factors.
81
What is an example of a density dependent population cycle?
Large numbers of moose leads to large number of wolves. Large amount of wolves leads to a decrease in moose population leading to a decrease in wolf population.
82
Effect of competition between species?
Negative effect on both species - typically species on the same trophic level.
83
Example of competition between two different trophic levels occur?
Two animals competing for a water hole.
84
What are the two main outcomes of competition between species?
Coexistence through resource partitioning - each species specializes on using a part of the resource. Competitive exclusion - One species excludes the other species from a community.
85
What is an example of coexistence?
Savanna herbivores migrate at different times of the year.
86
Effect of predation, parasitism, and herbivory?
One species benefits the other is negatively effected. One species uses the the other as a resource.
87
Predation
Predators kill and eat prey.
88
Herbivory
Herbivores consume all or part of a plant or alga. Not usually immediately lethal but causes strong selection for defensive adaptations.
89
Parasitism
Feed on host without killing normally.
90
Mutualism
Interaction that increases the fitness of both species.
91
What are some examples of mutualism in plants?
Mycorrhizae - fungi colonize the root system of a host plant, providing increased water and nutrient absorption capabilities due to high SA. Plant provides the fungus with carbohydrates formed from photosynthesis. Angiosperms and pollinators Reef corals have symbiotic algae in their tissues.
92
What is a dominant species?
Species with the most biomass in a community. Often primary producers
93
Keystone species
Species with large effects on other species. Often predators that regulate prey populations.
94
Example of bottom-up control
More grass introduced = more deer = more wolves
95
Example of top-down control
Wolves introduced = less deer = more grass
96
What are disturbances?
Removal of living producer biomass
97
What are examples of disturbances?
Fire, wind-throw, natural disasters.
98
Primary succesion
No soil - lichen - soil - grasses
99
Secondary succesion
Soil - grasses - herbs
100
What is ecological succesion
A process of community development
101
Pioneer vs mature communities post-fire succession.
Pioneer community is fast growing herbaceous plants with high dispersal ability that require a lot of light. Mature community are slow growing conifers with lower seed dispersal ability and can grow in shade. Shades out the pioneer community.
102
Stem exclusion stage
Phase in forest development where intense competition among trees for light, space, and resources results in the suppression and eventual death of less competitive individuals, leading to a thinning of the forest and dominance by a few species or individuals.
103
Flow of energy
Flows in one direction - enters as light from the sun and leaves in the form of heat. Can not be recycled.
104
Net primary production (NPP)
= Gross primary production - respiration by autotrophs The rate at which energy and fixed carbon become available to other trophic levels.
105
What limits terrestrial NPP? Aquatic?
Water and temperature. Nutrients
106
How much of the organic matter that plants produce do they respire?
About 50%
107
Where is a large amount of carbon stored?
Living plants store a large amount of carbon as biomass
108
What is the difference between the actual living biomass and the potential?
450 GtC vs 900 GtC Largely reduced due to forestry and agriculture.
109
Where is the most carbon stored?
Stored in soil. Most soil carbon is in northern forests and tundras.
110
What is trophic efficiency?
The percentage of energy fixed at one trophic level that is passed to the next trophic level. Typically about 10%
111
Why does soil hold so much carbon?
In forests herbivore consumption is low and most plant biomass goes into the soil.
112
Chemical cycle
CO2 available to producers is converted into CH20 which is consumed and then decomposers eventually return the CO2 back into the soil.
113
Preindustrial carbon cycle
Same amount of carbon enters and leaves the atmosphere each year. Photosynthesis = -100 Plant respiration + soil respiration = +100
114
Carbon cycle today
The amount of carbon in atmosphere has increased by 50%. Increased from 280ppm to 420. Combustion of fossil fuels and land use increasing carbon. Ocean is up-taking more carbon