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ecology Flashcards

1
Q

what is ecology?

A

the study of how organisms interact with their environment

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2
Q

what is an environment?

A

all of the living and non-living features of a particular location

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3
Q

what are the types of ecology?

A
  • organismal
  • population
  • community
  • ecosystem
  • global
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4
Q

what is organismal ecology?

A

interaction of an organism with its biotic and abiotic environment

morphological, physiological, and behavioural adaptations that allow individuals to live in a particular area

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5
Q

what is a population?

A

a group of individuals of the same species that live in the same area at the same time

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6
Q

what is population ecology?

A

how and why does population size change over time?

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7
Q

what is a community?

A

consists of populations of different species that interact with each other in a particular area

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8
Q

what is community ecology?

A

how do species interact in a community and what are the consequences?
- predation, parasitism, competition, and mutualism

a community’s response to disturbances

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9
Q

what is an ecosystem?

A

consists of all the organisms in a particular area along with nonliving components

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10
Q

what is ecosystem ecology?

A

how does energy flow and how do nutrients cycle through the local environment

considers both abiotic factors and biotic factors

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11
Q

what is the biosphere?

A

a thin zone surrounding the Earth and where all life exists - the sum of all terrestrial and aquatic ecosystems

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12
Q

what is global ecology?

A

how is the biosphere affected by global changes in nutrient cycling and climate?

human impacts on the biosphere

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13
Q

what is conservation biology?

A

the effort to study, preserve, and restore threatened genetic diversity in populations, species diversity in communities, and ecosystem function

all five levels of ecology are applied in conversation biology

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14
Q

what is biogeography?

A

the study of how organisms are distributed geographically

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15
Q

what determine the distribution and abundance of organisms?

A

the range of every species on Earth is limited by a combination of abiotic and biotic factors that occurred in the past, and occur in the present

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16
Q

what is range?

A

geographic distribution

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17
Q

what abiotic factors determine distribution of organisms, and how?

A

temperature
- organisms are limited in their ability to regulate their own temperatures
- enzymes only optimally work in one type of temperature otherwise denatures

climate
humidity and precipitation
geographical barriers (barriers to dispersal)
light quantity/ quality/ length
length of growing season
water availability
moisture
salinity

organisms tend to be adapted to a limited set of abiotic conditions

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18
Q

what is a niche?

A

the range of conditions that a species can tolerate and the range of resources it can use

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19
Q

what does a niche determine?

A

where an organism can live

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20
Q

what biotic factors determine distribution of organisms, and how?

A

the ability of a species to persist in a given area is often limited by biotic factors

presence of plants and animals consumed
distribution of predators/ parasites
adaptations
history of extinction (local)

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21
Q

what 2 major events have an impact on the organism dispersal?

A

1) theory of plate tectonics: the landforms and oceans that appear static now have been in constant flux for the entire history of life
2) climate change

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22
Q

what is organism dispersal?

A

the movement of individuals from their place of origin to the location where they live and breed as adults

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23
Q

how do humans influence organism distribution?

A

by hunting, clearing forests, and physically moving organisms around

moving species around could create an invasive species. the introduction of microorganisms can also affect distribution as it could cause disease

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24
Q

what is an invasive species?

A

if an exotic species (not native to the land) is introduced to a new area, spreads rapidly, and competes successfully with native species

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25
what is a biome?
regions characterized by distinct characteristics and dominant types of vegetation
26
what is the set of abiotic conditions for each terrestrial biome? and how are they determined?
they are determined largely by climate 1) temperature - enzymes work at optimal efficiency only in a few narrow range of temperatures - affects availability of moisture 2) moisture - terrestrial organisms constantly lose water to the environment through evaporation or transpiration - water loss must be reduced and lost water must be replaced 3) sunlight - photosynthesis 4) wind - exacerbates the effects of temperature and moisture - pushes flying organisms and plants around
27
what are the two most important factors in determining plant distribution?
temperature and moisture
28
what is NPP?
Net primary product (NPP) is the total amount of biomass generated by the fixation of carbon through photosynthesis per year minus the amount that is oxidized during cellular respiration. much higher on land than in oceans
29
what is biomass?
the total mass of organisms - dry weight of an organism
30
what mainly affects NPP?
temperature and moisture
31
why is NPP crucial?
represents organic matter that is available as food for organisms
32
how are photosynthesis, plant growth, and NPP maximized?
when the temperature is warm and conditions are wet because the enzymes will work efficiently
33
what are primary producers?
autotrophs - organisms that can synthesize their own food from inorganic sources typically they use solar energy to manufacture food via photosynthesis
34
what is GPP?
gross primary product: the total amount of chemical energy produced in a given area and time period
35
how do primary producers use the chemical energy?
1) cellular respiration: chemical energy is used to fuel cellular respiration to produce ATP, which is used to fuel more metabolic processes 2) growth and reproduction: the remaining chemical energy is used for growth and reproduction. energy is invested by primary producers in building new tissue or offspring is called NPP
36
are autotrophs efficient at capturing solar energy?
they are not efficient, only a fraction of sunlight is converted to chemical energy and only a fraction of this GPP is used to build biomass because only a fraction of light can be absorbed by the photosynthetic pigments.
37
what is the energy flow model?
energy flows from autotrophs through to other organisms in the form of biomass
38
describe the flow of energy?
primary consumers eat primary producers. secondary consumers eat primary consumers. tertiary consumers eat secondary consumers and so on. energy dissipates as it flows through ecosystems and is ultimately lost as heat, where as nutrients continue to cycle
39
what are decomposers?
they obtain energy by feeding on the remains of other organisms or waste products. all trophic levels contribute to the decomposer/ detritivore food web
40
what is detritus?
dead animals and dead plant tissues
41
what is a food chain?
one possible pathway of energy flow among trophic levels in an ecosystem. they are embedded in food webs
42
what is a food web?
includes all the organisms interacting in the ecosystem, and estimates the amount of energy transferred at each link.
43
what is the difference between detritivores and decomposers?
detritivores: consume (internally digest) dead organisms/ waste decomposers: break down dead organic matter externally
44
why does productivity decline at higher trophic levels?
- not all biomass is consumed/ digested - organic molecules are oxidized to produce ATP for metabolic processes (catabolism) - much of NPP is unavailable to herbivores - biomass material eaten by herbivores is used to power cellular processes - only a portion of biomass is converted to biomass of consumers via growth and reproduction
45
how does efficiency vary?
large mammals are more efficient at producing biomass than smaller animals because they have a smaller SA-V ration and lose less heat ectotherms are more efficient at producing biomass
46
what is biomagnification?
molecules that do not break down quickly in the environment can undergo biomagnification. increases in concentration at higher levels in the food chain
47
what is a biogeochemical cycle?
the path an element takes as it moves from abiotic systems through producers, consumers, and decomposers, and back again
48
how is decomposition rate influenced?
1) abiotic conditions 2) the quality of detritus as a nutrient source for the fungi, and archaea that accomplish decomposition 3) the abundance and diversity of detritivores present
49
what are the four major mechanisms to replace nutrients?
1) ions that act as nutrients are released when rocks weather 2) nutrients can blow in on soil particles or arrive dissolved in streams 3) carbon is added when primary producers fix carbon via photosynthesis 4) nitrogen is added when nitrogen-fixing bacteria convert molecular nitrogen (N2) int he atmosphere to usable nitrogen in ammonium or nitrate ions
50
describe the nitrogen cycle
- plants can take up nitrogen in the form of ammonium (NH4+) and nitrate (NO3-) - plants cannot directly use atmospheric nitrogen (N2) - nitrogen is used for many organic molecules - nitrogen-fixing bacteria form mutualistic associations with the roots of plants and convert nitrogen gas to ammonium ions
51
describe the carbon cycle
- CO2 is removed from the atmosphere by photosynthesis and chemical processes - CO2 is added to the atmosphere through respiration - much is released through deforestation as trees are carbon sinks - held in the ocean - fossil fuels
52
what is biofuel?
a fuel derived directly from living matter - a good biofuel should provide a net energy gain over energy sources use to produce the biofuel
53
what are the four most common types of species interaction?
1. commensalism (+/0) 2. competition (-/-) 3. consumption (+/-) 4. mutualism (+/+)
54
what is competition?
occurs when individuals use the same resources - resulting in lower fitness for both
55
what are the two types of competition?
1) intraspecific competition: competition that occurs between members of the same species. the competition for space, sunlight, food, and other resources intensifies as the population density increases - major cause of density-dependent growth 2) interspecific competition: competition between individuals from different species that use the same same limiting resource - ties in with the concept of niche - occurs when two niches overlap - because of this there is either symmetric (both species experience a similar decrease in fitness due to the overlap of their niches) competition or asymmetric competition ( when one species suffers a greater decline in fitness than the other species - the stronger competitor drives out the weaker competitor)
56
what is the competitive exclusion principle?
two species that occupy the exact same niche cannot coexist
57
what happens when the two niches don't completely overlap?
we get two different types of niches 1) fundamental niche - the total theoretical range of environmental conditions that a species can tolerate as well as required resources - only abiotic factors (neglect species interaction) 2) realized niche - portion of the fundamental niche that a species actually occupies, given limiting factors such as competition with other species - generally smaller than the fundamental niche - both abiotic and biotic factors considered strong competitors can exclude the species from parts of its fundamental niche strong predators can remove individuals from parts of the fundamental niche weak predators/ competitors can reduce the quality of parts of the niche
58
what is a fitness trade off?
inevitable compromises in adaptation the ability to compete for a particular resource can require time and energy that can no longer be invested in other traits or activities that contribute to fitness
59
what is niche differentiation?
an evolutionary change in resource use, caused by competition over generations
60
what is character displacement?
the evolutionary change that occurs in species traits, and that enables species to exploit different resources - makes niche differentiation possible
61
what is consumption?
occurs when one organism eats or absorbs nutrients from another. the interaction increases the consumers fitness but decreases the victims fitness 1) herbivory: takes place when herbivores consume plants and algal tissues 2) predation: occurs when a predator kills and consumers all or most of another individual. the consumed individual is called the prey 3) parasitism: occurs when a parasite consumes relatively small amounts of tissue or nutrients from another individual, called the host. usually takes place over a long period and is not necessarily fatal. parasites are usually small relative to their host - endoparasites: live inside - ectoparasites: live on the outside -parasitoidism: when an organism is free living as an adult but endoparasitic as a larva (fatal for host)
62
what are constitutive and inducible defences?
constitutive: traits that allow individuals to avoid being eaten (mimicry) - effective but energetically expensive inducible defences: physical, chemical, and behavioural defensive traits that are induced in the prey in response to the presence of a consumer - efficient but slow - favoured by natural selection
63
what is bottom-up control?
driven by the presence or absence of the producers in the ecosystem productivity in an ecosystem is limited by growth of primary producers
64
what is top-down control?
the presence of certain consumers can significantly change the number of species present in a community and the abundance of each remove the top predators from a community and seeing what happens
65
what is a keystone species?
much greater impact on distribution and abundance of the surrounding species than its abundance and total biomass
66
what is a climax community?
stable community - does not change over time
67
what is a disturbance?
any strong, short-lived disruption to a community that changes the distribution of living and/ or nonliving resources. can be short term or long term or human created
68
what is a short-term disturbance?
wave action, floods, fire, volcanic eruption, invasive species
69
what is a long-term disturbance?
climate shifts, evolutionary innovations, extinction of prey or mutualist, change in river channels
70
what is a disturbance regime?
the frequency and severity of a disturbance
71
what is succession?
the recovery following a disturbance
72
what is primary succession?
- occurs when a disturbance removes the soil and its organisms as well - colonization of a new habitat
73
what is secondary succession?
occurs when a disturbance removes some or all of the organisms but leaves the soil intact, including the seeds and microorganisms within
74
what is a successional pathway?
the specific sequence of species that appears over time
75
what are pioneering species?
weed - plant that is adapted for growth in disturbed soils because soil is often disturbed when biomass is removed, weeds tend to thrive at the start of secondary succession
76
what are the characteristics of pioneering species?
- rapid growth - relatively fast reproduction - R selected; lots of small seeds - short life span - tolerant of harsh abiotic conditions/ broad niche - generalists - sometimes self-fertile - weak competitors - good at dispersal
77
what are characteristics of species in a climax community?
- strong competitors - large - longer life span - takes longer to reach reproductive maturity - lower tolerance of harsh abiotic conditions - K-selected (more investment in offspring, less offspring) - biotic interactions are more important
78
what is the role of existing species on subsequent species during succession?
1) facilitation: takes place when the presence of an early-arriving species makes conditions more favourable for the arrival of certain later species. but the facilitation is not purposeful or altruistic; it is just a byproduct of the way of life of the early-arriving species 2) tolerance: existing species do not affect the probability that subsequent species will become established. once again, tolerance is not purposeful, just an absence of influence of early-arriving species on late-arriving species 3) inhibition: occurs when the presence of one species inhibits the establishment or regrowth of another
79
what four factors affect the population growth rate?
1) birth 2) death 3) immigration 4) emigration
80
population growth
- represented by r max - the per capita rate of increase of each population is likely lower than r max - r depends on life history and varies among species and populations
81
exponential growth
occurs when r does not change over time r is density independent does not continue indefinitely
82
logistic growth
population growth is density dependent r declines populations growth rate (K-N)/K dependent on population size
83
what is carrying capacity (K)
the max number of individuals in a population that can be supported in a particular habitat over a sustained period of time changes depending on the conditions - optimal conditions = higher K - marginal conditions = lower K

bio 121 (2 decks)

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