Unit 8 - Ecology Flashcards
population
- a group of the same species living in a specific area
community
- all the species that inhabit a particular area and their interactions (predation, comptetiton, parasitism)
ecosystem
- community + abiotic factors
biosphere
- the global ecosystem (all the life on the planet and the physical environment: land, ocean atmosphere)
how do organisms respond to changes in the environment
- behavior mechanisms
- physiological mechanisms
behavioral mechanisms
- taxis and kinesis
- migration
physiological mechanisms
- hibernation/estivation
- circadian rhythyms
- phototropism
- photoperiodism
taxis
- the movement of an organism in response to a stimulus
positive taxis
moving towards the stimulus
negative taxis
moving away from the stimulus
phototaxis
towards or away from light
chemotaxis
immune system
photoreceptors
these are specialized cells that detect light that determinen how an organism responds to light
ex: eyes, ears
kinesis
- random movement in response to a stimulus
nocturnal: active at night
diurnal: active during the day
migration
- a regular long distance change in location
- move to water, food, temperature
**receptors allow organisms to know how to move
(ex: birds use magnetism and amt of light)
circadian rhythms
- physical, behaviorals, and mental changes in a 24 hour cycle
- hormones
- photo receptor
hibernation / estivation
state of inactivity and reduced metabolic rate to survive extreme weather conditions
- this happens because its more taxing (harder) to find food/water
phototropism
is the growth of a plant in response to light; it’s how plants “bend” toward a light source to maximize photosynthesis
estivation
hibernation in desert animals???
photoperiodism
is an organism’s physiological response to the length of day or night; helps organisms adapt to seasonal changes in their environments
innate behaviors
genetically hardwired behaviors
learned behaviors
organisms watch and learn behaviors
examples of innate behaviors
- suckling in mammals
- swimming in whales
- building a nest
examples of learned behaviors
- habituation
- associative learning
habituation
organisms get used to people and we are not a threat
associative learning
organisms learn certain organisms taste terrible
metabolism
all the chemical reactions in an organism
- generates heat
relation to ecology
- food = ecology
- measured in calories
- food is limited (limits population size)
body temperature
- must be regulated because if temperature becomes too hot, it denatures proteins
- if temperature decreases, H2O freeze and cells will rupture
endotherms
- “warm blooded”
- regulates body temperature (shivering, sweating, vasoconstriction)
- can live in multiple regions
**countercurrent - ducks heat exchange
ectotherms
- “cold blooded”
- use physical means to maintain temperature
- use sun to sunbathe/use shade to cool off
- aggregate
- consume less food
- temp. changes based on surroundings
metabolic rate
- to measure the amount of O2 used and CO2 produced
- number of calories required to perform basic life sustaining function; how fast fuel is used to keep cells functioning
metabolic rate: large vs. small endotherms
- larger surface area to volume ratio requires higher metabolic rate
food chain
shows the transfer of matter and energy from one organism to the next
- arrows represent the transfer of energy
food web
shows many food chains
food web: base
- autotrophs: producers
- chemiotrophs: take inorganic molecules and turn into org. molecules
(nonphotosynthetic, ex: bacteria)
food web: heterotrophs
consume food for energy
primary consumers
- heterotrophs
- herbivores
secondary & tertiary consumers
- omnivore & carnivore
food web: decomposers
break down and recycle nutrients
- ex: bacteria and fungii (saprophyte)
factors that influence how much available energy is possible in an ecosystem
- abiotic
- biotic
abiotic factors
- nonliving factors that affect populations
ex: temp, rainfall, water, amount of sunlight, pH, wind
biotic factors
living factors that affect populations
- predator/prey relationships, food, competition for food, competition for mates, symbiotic relationships
trophic levels
- energy is NOT conserved – lost as heat & used for metabolism
how can a change in sunlight affect the number and size of trophic levels?
increase in sunlight = increase in number and size of trophic levels
how can a change in producers affect the number and size of other trophic levels?
increase number and size of other levels
natural selection and ecology
in 1977 - there was a drought for 551 days on the Galapagos Islands
80% of the finches with smaller beaks died. the finches with larger beaks were able to survive
why were finches with larger beaks able to survive?
- the seeds that were left were harder to crack; the larger beaks were able to crack them
net gain in energy
a surplus in food which means populations get larger
net loss in energy
not enough food so populations shrink
exponential growth
- population growth as if there are unlimited resources
- per capita (indiv.) rate is the same
- “J” shaped curve
- this is what the invasive species follow
population density
the measurement of how many individuals are in a specific area
what can happen when population density changes
- immense competition if population increases because of competition for resources
limiting factors
factors that limit how big a population can grow
ex: shelter, water, predators, energy/nutrients
carrying capacity (K)
- maximum population for an area
- as population approaches carrying capacity growth rate slows
density dependent limiting factors
affect large, dense populations
ex: disease, competition for food, predators
density independent limiting factors
affects any population regardless of size
ex: natural disaster, human impact/pollution
logisitic growth
- per capita growth rate gets smaller as the population approaches carrying capacity (K)
K selected species
live at carrying capacity
R selected species
grow so rapidly its like experiencing exponential growth
interspecific interaction
how different species interact with other species
examples of interspecific interaction
- competition for food
- symbiotic relationships
- invasive species
interspecific competition
- different species compete for a resource that limits growth and survival
competitive exclusion
- when two populations use the exact same resource at the same time
- 2 species occupy the same niche and compete for the same resources; one beats the other
ecological niche
the role an organism plays in a community
- refers to the interrelationship of a species with all the biotic and abiotic factors affecting it
fundamental niche
- all of the conditions a species needs to survive (food, H2O, mates)
- doesn’t include the interactions with other species
- doesn’t exist
realized niches
the conditions need for species to survive + interactions with other species
predation (+/-)
- as prey increases, the predator population increases but lags
symbiosis
- two different species interacting in a close relationship
mutualism
+/+
- both organisms benefit (ex: bees & flowers)
commensalism
+/0
- one organism benefits and the other unaffected
ex: bird nests and trees
parasitism
+/-
- one organism benefits & other (host) is harmed
ex: tick & dog
species diversity
- species richness
- species abundance
species richness
- the amount of diff. species in a community
species abundance
- the number of each of those different species
ecological succession
- the process by which the mix of species and habitat in an area changes over time
- gradually, these communities replace another until a climax community is reached, or until a disturbance like a fire occurs
primary succession
- starts with bare rock (nothing)
- pioneer organism: lichen (breaks down rock)
secondary succession
- happens after some sort of disaster
- ex: fire
biodiversity entails
- genetic diversity
- species diversity
- ecosystem diversity
genetic diversity
- diversity within species
- variation in alleles
ex: pocket mice
- more variation = more resilience if the environment changes
species diversity
- different types of species (richness and abundance)
- different numbers of species in an ecosystem
**overreliance on 1 type of resource decreases the probability the ecosystem will be stable
ecosystem diversity
- diversity between ecosystems
- humans deplete -> potential medicines
- water cycle
- CO2 cycling
what claim can we make about the biodiversity of this corn field
- monoculture: one crop, “clones”
- if a parasite infects the corn monoculture, many of the crops will die
keystone species
- a species that has a very large impact on a community disproportionate to the amount of individuals in a species
ex: wolves, seals
***the diversity of a species within an ecosystem may influence the organizatoin of the ecosystem
hot and dry ecosystems
- low biodiveristy
- due to abiotic factors: H2O
cooler & wetter ecosystems
- high biodiversity
- abiotic factors: water surplus
the effects of keystone species on the ecosystem are disproportionate relative to their abundance in the ecosystem, and when they are removed from the ecosystem, the ecosystem often collapses
6 major ways humans are disrupting ecosystems and causing extinction of species on earth
- habitat loss
- invasive species
- population growth
- pollution
- climate change
- overexploitation
habitat loss
- reason: human population growth
- urbanization requires space, resources, & food
invasive species
non-native species with no natural predators
- outcompete natives
native species
their ecological niche is part of the existing community / ecosystem
non-native species
an introduced species to an area that is not native to the region
- their presence is not necessarily harmful or destructive
biological magnification
eutrophication
- N + P runs off into local waters
- phytoplankton uses these nutrients and grows exponentially
- phytoplankton dies off
- aerobic bacteria break down phytoplankton and bacteria grows exponentially
aerobic bacteria
breaks down phytoplankton
- consume O2 and resources
overexploitation
removal of more species than are born
climate change
- warming of our atmosphere, oceans, and land (abiotic factors)
if producer populations require specific temperature and those temperatures change…
this has an effect on all the population that rely on these producers
greenhouse gases + greenhouse effect
-GHG’s trap heat in our atmosphere (CO2)
- increased GHG’s increase the amount of heat trapped in the atmosphere
**organisms cannot choose to adopt or wish for a mutation. they either survive and reproduce or they die
dutch elm disease
- causes wilt and death in all species of elm disease
- caused by invasive fungal pathogen
- elm bark beetles spread it when feeding on elm trees
meteor impact (or asteroid)
- blocks sunlight
- producers cannot do photosynthesis
- “ripples” through trophic levels
continental drift
- angle and intensity of sun is different in different latitudes
el nino
- unpredictable change in current
- current brings warm water towards South America
- during El Nino, Pacific coast gets a lot of rain and Indonesia dries out
abiotic factors: examples
- sunlight
- water availability
- soil composition and nutrients
- temperature
- pH
- humidity
- salinity
- air currents or wind
biotic factors: examples
- plants
- animals
- decomposers
- pollinatprs
- predators and prey
- parasites
ecology
the study of interactions between organisms and their environments
how does energy transfer through trophic levels
energy decreases as you move up each level; ~10% transfers from one level to the next
