Unit 8: Ecology Flashcards
(124 cards)
1
Q
Biotic
A
= living (organisms – behaviors & interactions between organisms)
2
Q
Abiotic
A
nonliving (temp, water, salinity, sunlight, soil)
3
Q
Climate
A
long-term prevailing weather conditions in a particular area, (temperature + precipitation + sunlight + wind)
4
Q
Macroclimate
A
work at seasonal, regional or local level
5
Q
Microclimate
A
small-scale environmental variation (eg. under
a log)
6
Q
Climate change effect on species
A
some species may not survive
shifting ranges
7
Q
Biomes
A
major types of ecosystems that occupy very broad geographic regions
8
Q
What abiotic factors determine biomes?
A
climate, temperature, salinity, soil type, amount of sunlight, and amount of water that is available
9
Q
Role of Abiotic factors in the formation of biomes
A
The create suitable or ill suitable conditions for various life forms to live in
- climate influences the distribution of plants - temperature & perception help to determine what type of biome it is
- pH & composition of rocks limits the distribution, helping certain dominate plants to thrive
10
Q
How do biotic factors help biomes?
A
The primary producers and autotrophs (biotic factors) support the rest of the biome.
11
Q
Population:
A
group of individuals of same species living in a particular geographic area
12
Q
Community
A
group of populations of diff species in an area
13
Q
Ecosystem
A
community of organisms + physical factors
14
Q
Landscape
A
mosaic of connected ecosystems
15
Q
biosphere
A
global ecosystem
16
Q
Global climate patterns
A
Sunlight intensity, Air Circulation & Precipitation Patterns, Ocean Currents, Mountains affect rainfall
17
Q
Climograph
A
plot of annual mean temperature & precipitation in a particular region
18
Q
Tropical Rain Forest
A
A terrestrial biome characterized by relatively high precipitation & temperatures year-round.
19
Q
Desert
A
A terrestrial biome characterized by very low precipitation
20
Q
Savana
A
A tropical grassland biome w/ scattered individual trees, large herbivores & maintained by occasional fires/drought
21
Q
Chaparral
A
Biome characterized by mild, rainy winters & long, hot, dry summers; dominated by dense, spiny evergreen shrubs
22
Q
Temperate Grassland
A
A terrestrial biome that exists at midlatitude regions & is dominated by grasses & forbs.
23
Q
Northern Coniferous Forest
A
A terrestrial biome characterized by long, cold winters and dominated by cone-bearing trees.
24
Q
Temperate Broadleaf Forest
A
A biome located throughout midlatitude regions where there is sufficient moisture to support the growth of large, broadleaf deciduous trees
25
Tundra
A terrestrial biome at the extreme limits of plant growth. At the northernmost limits, it is called arctic tundra, and at high altitudes, where plant forms are limited to low shrubby or matlike vegetation, it is called alpine tundra.
- long, cold winters w/ high winds & cold temperatures, less precipitation, low biotic diversity
26
Lakes
bigger & deeper than ponds. Some of the water in lakes is in the aphotic zone, where there is too little sunlight for photosynthesis. Plankton and plants = producers
27
Wetlands
saturated soil, very little water present at some times, but deeper amounts of water at other times. They are also home to specialized plants called hydrophytes, which are able to grow in super wet areas.
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Streams & RIvers
continuously moving bodies of water that carry large amounts of water from the source, or headwater, to a lake or ocean.
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Estuaries
brackish water, a mix of freshwater & salt water. Estuaries are unique ecosystems, providing animals w/ food, shelter, and a place for breeding and nesting, as well as a place for resting during migrations.
30
Intertidal zones
submerged w/ water during high tide & exposed to the air during low tide. The zone can take many forms, from sandy beaches to rocky cliffs.
31
Oceanic Pelagic Zone (Open Water)
organisms inhabiting the zone do not come in contact w/ the bottom or the shore throughout their lives. The pelagic zone is nutrient-poor. The large fish find their food by swimming long distances or drifting w/ currents and feeding on nutrient-deficient organisms.
32
Coral Reefs
structures that provide habitat for the fish and invertebrate species that make up the ecosystem. Hard corals create the reef itself. They typically consist of a layer of colonial polyps that live on the surface of a calcium carbonate skeleton that is secreted by the coral polyps
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Marine Benthic Zone
begins at the shore and extends to the bottom of a waterbody. It is found all over the world. Only a small amount of sunlight reaches this zone. characterized by low temperature & high pressure.
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Biogeography
geographic distribution of
species
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Biogeography Factors
Dispersal, Behavior, Biotic & Abiotic
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Dispersal that affect biogeography
movement away from area of origin
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Behavior that affect biogeography
Habitat Selection
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Biotic factors that affect biogeography
other species, food resources,
competition, pollinators, predators
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Abiotic Factors that affect biogeography
temp, water, oxygen, salinity,
sunlight, rocks & soil
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Density
individuals / area
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Dispersion
pattern of spacing between
individuals
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Determining population size and density
Count every individual, Random sampling, Mark-recapture method
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Patterns of Dispersal
Clumped, Uniform, Random
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Clumped Dispersal
most common; near required resource
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Uniform Dispersal
usually antagonistic interactions
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Random Dispersal
unpredictable spacing, not common in nature
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Demography count
Additions: birth & immigration,
& subtractions: death &
emigration
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Survivorship Curve
represent # individuals alive at
each age
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Type I
low death rate early in life (humans)
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Type II
constant death rate over lifespan (squirrels)
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Type III
high death rate early in life (oysters)
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Change in Pop Size calculation
birth-death
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Zero Pop Growth
Birth = Death
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Exponential population growth
ideal conditions,
population grows rapidly (just goes up in like u-shape)
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Exponential Growth Equation
dN/dt = change in population = r*N
r = growth rate of pop.
N = population size
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Logistic Model & Carrying capacity
Unlimited resources are rare! incorporates carrying capacity (K) K = maximum stable population which can be
sustained by environment
(looks like s)
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Logistic Growth Equation
dN/dt = change in population
= rN (K-N/K)
r = growth rate of pop.
N = population size
K = carrying capacity
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Life History
traits that affect an organism’s
schedule of reproduction & survival
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3 Variables of Life History
# offspring produced per reproductive episode
Age of sexual maturation
How often organism reproduces
# offspring produced per reproductive episode
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Semelparity
Big-bang reproduction
Many offspring produced at once
Individual often dies afterwards
Less stable environments
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Iteroparity
Repeated reproduction, Few, but large offspring, More stable environments
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Critical factors:
survival rate of offspring and repeated reproduction when resources are limited
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K-selection
pop closed to carrying capacity, Live around K, High prenatal care, Low birth numbers, Good survival of young, Density-dependent, humans
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r-selection
maximize reproductive success, Exponential growth, Little or no care, High birth numbers, Poor survival of young, Density independent, ex: cockroaches
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Factors that limit population growth
Density Dependent & Density Independent
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Density-Dependent factors:
population matters
i.e. Predation, disease, competition, territoriality,
toxic wastes, physiological factors
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Density-Independent factors
population not a factor
i.e. Natural disasters: fire, flood, weather
If there is a drought and plants wither -> certain animals cant eat and that affects everyone else
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Interspecific competition
Can be positive (+), negative (-) or neutral (0)
resources are in short supply
Species interaction is -/-
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Competitive exclusion principle
2 species cannot coexist in a community if their niches are
identical
The one w/ the slight reproductive advantage will eliminate the other
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Resource partitioning
differences in niches that
enable similar species to coexist
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Ecological niche
the sum total of an organism’s use of abiotic/biotic resources in the environment
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Fundamental niche
niche potentially
occupied by the species (entire set of conditions to reproduce/survive)
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Realized niche
portion of fundamental niche the species actually occupies after interactions with other species (predation and especially competition) have been taken into account.
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competitive exclusion in interspecific competition.
2 species can't coexist if they occupy exactly the same niche (competing for identical resources). Two species whose niches overlap may evolve by natural selection to have more distinct niches, resulting in resource partitioning.
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Interspecific interactions
Competition (-/-), Predation (+/-), Herbivory (+/-), Symbiosis – parasitism, mutualism, commensalism
Facilitation (+/+ or 0/+)
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Cryptic coloration
camouflaged by coloring
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Aposematic or warning coloration
bright color of poisonous
animals
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Batesian mimicry
harmless species mimic color of harmful species
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Mullerian mimicry
2 bad-tasting species resemble each other; both to be avoided
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Herbivory
plants avoid this by chemical toxins, spines, & thorns
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Symbiosis:
2+ species live in direct contact with one
another: Parasitism (+/-), mutualism (+/+), commensalism (+/0)
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Species diversity
= species richness (# of
different species) + relative abundance of each
species.
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Simpson Diversity Index:
Calculate diversity
based on species richness & relative abundance
Highly diverse communities more resistant to invasive species
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Simpson’s Diversity Index EQ
1- Sum of (n/N)^2 n=total # organisms in a species, N=total organisms in all species
High D(close to 1) = high biodiversity, Low D(close to 1)=less biodiversity
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Invasive species
Organisms that become established outside
native range
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Characteristics of Invasive species
Tolerates a wide range of conditions, long growing season, short generation
time. few natural controls such as predators, disease, or insects, Disperses itself with ease, Produces lots of seeds or eggs, New location has climate and environmental
conditions similar to native habitat
87
Trophic Structures
determined by the feeding relationships between
organisms.
Trophic levels = links in the trophic structure
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food chain.
The transfer of food energy from plants -> herbivores -> carnivores -> decomposers
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What limits the length of a
food chain?
Inefficiency of energy transfer along chain, Long food chains less stable than short chains
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food webs.
Two or more food chains
linked together
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Dominant species:
has the highest biomass or is the most abundant in the community
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Keystone species:
exert control on community structure by their important ecological niches
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Ecological succession:
transitions in species
composition in a certain area over ecological time (comes in after something dies)
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Disturbance
changes a community by
removing organisms or changing resource availability (fire, drought, flood, storm, human activity)
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Primary Succession
Plants & animals invade where soil has not yet formed
Ex. colonization of volcanic island orglacier (plants growing on volcano)
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Secondary Succession
Occurs when existing community is cleared by a
disturbance that leaves soil intact Ex. abandoned farm, forest fire
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Biogeographic Factors
Latitude: species more diverse in tropics than poles
Area: larger areas more diverse
98
Biogeographic Islands
Influenced by size & distance
Larger islands: greater immigration, lower extinction
Far from mainland: immigration falls, extinction rates increase
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Ecosystem
*** IMPORTANT: sum of all populations living in a specific area (biotic community) + abiotic
factors with which they interact
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Where is energy supplied from?
the sun
101
can energy be recycled?
no
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autotrophs
(“self feeders”) = primary producers, & are usually photosynthetic (plants
or algae).
use light energy to synthesize sugars & other organic compounds.
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Heterotrophs
(“other feeders”) – can’t make own
food
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primary consumers
Herbivores that eat primary producers
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secondary consumers
Carnivores that eat herbivores are called
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tertiary consumers
Carnivores that eat secondary consumers
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detritivores/decomposers
group of heterotrophs, get energy from detritus, nonliving organic material, & play an important role in material cycling
108
Primary production
amount of light energy -> converted to chemical energy
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Gross primary production (GPP)
total primary production in an ecosystem
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Net primary production (NPP)
gross primary production minus the energy used by the primary producers for respiration (R): storage of chemical energy available to consumers in an ecosystem
NPP = GPP – R
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Energy Transfer between Trophic Levels
Only 10% efficient
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Biogeochemical cycles
cycles: nutrient cycles that contain both biotic & abiotic components
organic -> inorganic parts of an ecosystem
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Carbon Cycle
CO2 removed by photosynthesis,
added by burning fossil fuels
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Nitrogen Cycle
Nitrogen fixation: N2 -> plants by bacteria
Nitrification: ammonium -> nitrite -> nitrate, Absorbed by plants Denitrification: Release N to atmosphere
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Why is biodiversity important?
1) More diverse ecosystems = more stable & able to resist threats
2) Many drugs have been derived from plant, fungi & bacterial species.
3) More likely for species to escape extinction if new pathogen emerges
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Habitat loss
Human alteration of habitat is the single greatest threat to biodiversity
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4 major loss of biodiversity
Habitat loss, introduced species, global change, overharvesting
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Introduced species
invasive/nonnative/exotic
species
119
Overharvesting
harvest wild plants & animals
120
Global change
alter climate, atmosphere, &
ecological systems -> reduce Earth’s capacity to sustain life
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Bioremediation
use of organisms (prokaryotes,
fungi, plants) to detoxify polluted ecosystems
122
Bioaugmentation
introduce desirable species
(eg. nitrogen-fixers) to add essential nutrients
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Human activities changing the earth
overpopulation, pollution, burning fossil fuels (CO2 increase), & deforestation, depleting atmospheric ozone
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Biological Magnification
Toxins become more concentrated in
successive trophic levels of a food web
Toxins can’t be broken down & magnify inconcentration up the food chain
