Studied by 47 people
Edward O. Wilson
leading expert in ants, sociobiology, theory of island biogeography
biological community
consists of all of the populations within a defined area
species interactions
scientists analyze the effect of one species on the fitness of another
importances of interactions
may affect distribution and abundance
species act as agents of natural selection when they interact
the outcome is dynamic and conditional
commensalism (+/0)
one species benefits while the other is unaffected (sharks/manta rays with remoras)
competition (-/-) or (+/-)
usually both species are negatively effected because used up energy (barnacles with space on rock)
intraspecific
within species - density dependent growth
interspecific
between species
Joseph Connell’s experiment
studies the intertidal zonation of barnacles in Scotland : Cthamalus and semibalanous (competition in different tides)
consistent with the experiment, the upper limit of the intertidal was determined by
tolerance to environmental factors
consistent with the experiment, the lower limit of the intertidal zone was determined by
competition/predation
what happens when niche overlap occurs?
if one species is a stronger competitor, it will drive the other to extinction
competitive exclusion principle
it is not possible for two species with the same niche to coexist
what happens when niche overlap occurs, but is incomplete?
weaker competitor will persist in area of non-overlap
fundamental niche
total theoretical range of conditions a species can tolerate
realized niche
range of conditions a species actually occupies
natural selection in niche differentation
predicts that traits that reduce competition will be favored and increase
character displacement
change in species’ traits
niche differentation
change in resource use
consumption (+/-)
one species benefits at the cost of the other
herbivory
herbivores eat plants (+/-)
parasitism
lamprey attach to fish and extract nutrients (+/-)
predation
sea-stars eating mussels (+/-)
when predator and prey interact over time this can lead to
co-evolutionary arms race - a repeating cycle of reciprocal adaptation - major driver of evolutionary change
traits that reduce competition
constitutive (standing defenses)
mimicry (close resemblance to another species)
inducible defense (produced in response to a predator)
batesian mimicry
looks toxic but isnt
mullerian mimicry
harmful species resemble each other
mutualism (+/+)
both species benefit
ex. clown fish live in anemone
community structure attributes
total # of species (richness)
sum of interactions among species
relative abundance of species (evenness)
physical attributes (abiotic + biotic)
species richness
number of species
species diversity
weighted measure that incorporates relative abundance
bottom-up effects
affects abundance of primary producers (abiotic) nutrients
top-down effect
generally consumptive (biotic) like predators
Bob paine study
intertidal zonation in washington sea stars vs mussels
trophic cascade
when a change in top-down control causes effects two or three links away in a food web
clements on predictability of communities
communities are stable, orderly and highly predictable
gleason on predictability of communities
communities are not stable nor predictable (matter of chance)
disturbance
any strong, short-lived disruption to a community that changes the distribution of living and nonliving resources
disturbance regime
characteristic of type of disturbance in a community with predictable frequency and severity
succession
recovery that follows disturbance
primary succession
soil and organisms gone
secondary succession
soil intact but some/most organisms gone
an ecosystem consists of
all the communities in an area along with abiotic components
ecosystem ecology is focused on
flow of energy and nutrients
gross primary productivity (GPP)
total photosynthesis
net primary productivity (NPP)
photosynthesis used for growth and reproduction
globally, humans use ~1/4 of all NPP
energy flow model
energy flows through consumption or decomposition - energy is lost through heat at each site
pyramid of productivity
biomass decreases with higher trophic levels
biomagnification
molecules that increase with trophic level
ex. heavy metals and pollutants
nutrient cycling
decomposition is slowest process, returns nutrients to the soil
global water cycle
reservoirs - oceans/rivers and lakes
natural processes - precipitation, evaporation, transpiration
human impacts - gw depletion, concrete, deforestation, fracking
global nitrogen cycle
reservoirs - atmosphere N2
natural processes - lightning and bacteria
human impacts - pollution, grasslands, run off from fertilizer
global carbon cycle
reservoirs - ocean, terrestrial ecosystems, atmosphere
natural processes - photosynthesis, respiration
human impacts - agriculture, burning fossil fuels
biological effects of climate change
species have physiological and environmental constraints, animals will be forced to move, adapt or go extinct
geographic range shifts
species moves in a certain direction
ex. mountain pine beetle infesting pines
phenology shifts
change in the timing of events
ex. arctic hare changing colors
evolutionary adaptations
shifts in allele frequency in a population
ex. toni owl, ladybugs
ocean acidification
leading to dissolving shells in oysters **warm water holds less oxygen
6th mass extinction effects
12 percent of all lizards died off
melomus habitat flooded by sea
Global changes in NPP
decreasing in the sea and on land
jane goodall
british primatologist - world’s l;eading expert on chimps
conservation biology
dedicated to studying, preserving, and restoring biodiversity; also concerned with ecosystem function
genetic biodiversity
number and frequency of alleles/genes in a species; represents adaptive capacity of a group
species diversity
richness and evenness of species
ecosystem diversity
number of species in each trophic level and number of trophic levels
biodiversity is
dynamic; affected by mutations, natural selection, genetic drift, gene flow, speciation, and extinction
ecosystem function
= sum of biological / chemical processes that characterize an ecosystem; includes primary production, nutrient cycling, and decomposition
how many species are alive?
estimated 5-100 million only ~1.5 million named
as habitat size increases
number of species increases
theory of island biogeography
islands have less species than terrestrial habitats of the same size
as latitude increases
number of species decreases
biodiversity hotspots
regions with at least 1500 endemic plant species from which 70% or more of traditional vegetation has been lost
endemic species
species within a limited geographic range
modern extinction rates
100-1000 times higher than average; 41,000 species at risk
habitat loss includes:
logging, deforestation, damming rivers, plowing prairies, excavating, development, fragmentation
overexplotation
unsustainable removal of organisms from the natural environment ex. overhunting/overfishing
invasive species
when a nonnative species has documented negative effects
exotic species
nonnative to an area it has been introduced to (no negative data)
pollution includes
industrial pollutants, pharmaceutical drugs, nutrient pollution, garbage
superfund
spot where scientists try to remove chemicals from sediments
importance of biodiversity
drives productivity-related to number and type of species present
resistance
how much a community is affected by a disturbance
resilience
how quickly a community recovers
ecosystem services
all direct and indirect benefits that humans derive from organisms and ecosystems; valued at 125 trillion dollars per year
provisioning services
provide raw materials - food, fuel, medicine, building materials, water
regulating services
water purification, flood control, waste decomposition
cultural services
aesthetics, recreation, education, health
supporting services
primary productivity, nutrient cycling, pollination, pest control
sustainability
the concept of creating ways for humans to live off the resources that are being replaced of sustained
what is niche differentation?
the evolution of traits that reduce niche overlap and competition
the relationship between corals and photosynthetic protists they harbor is an example of
mutualism
inducible defenses
not always present; do not prevent attackers
do result from coevolutionary arms races and are only produced when needed
pioneer species tend to have high [blank] and lower survivorship
fecundity
what is the main global reservoir of nitrogen?
N2 gas from the atmosphere
what is the longest living reservoir for carbon?
fossil fuels
devegetation has what effect on ecosystem dynamics
it increases nutrient export
what is a biodiversity “hotspot”
an area with high species richness and high threat to those species
what is the primary threat in marine environments
overexploitation
Note
Flashcard