ap bio - unit eight (ecology)

symbiosis

occurs between two organisms that are close in proximity and which one directly relies on the other

amensalism

uneven symbiosis; one organism hurt another without gain or loss

ex: penicillan kills the bacteria of bread mold

commensalism

symbiotic; one organism is benefitted and the other is unharmed

ex: birds building nests in trees

intraspecific compeition

not symbiotic; occurs within the species

interspecific competition

not symbiotic; occurs between different species, competing for habitat, food, and materials

facilitation

indirect symbiosis; one benefits and the other is unaffected

ex: juncus in salt marshes

mutualism

symbiotic; both organisms are benefitted

ex: bees and flowers

parasitism

symbiotic; one is benefitted and one is harmed

ex: whales with barnacles on blow holes

predation

indirect symbiosis; predator directly benefits, once the prey is eaten the relationship ends

ex: carnivory

disruptions/disturbances

cause a change of balance in an ecosystem

causes:

• invasive species

• disease or parasite

• environmental issues

• natural cycles

succession

natural, gradual changes in the types of species that live in an area; either primary or secondary

primary succession

creating life in an area where no life previously existed; begins in a place without any soil; takes a long time

ex: island from volcanic eruption

pioneer species (primary succession)

• licenses/mosses break down nutrients in rocks

• weathering and erosion

• sand and soil eventually are created

• seeds are blown in or carries by animals

• soil gets enriched as plants die

• medium mammals make habits and plant life increases

secondary succession

re-stabilization that follows a disturbance in an area where life has formed an ecosystem; organisms are destroyed by the soil is safe (seeds of weeds, grasses, and trees)

pioneer species (secondary succession)

• grasses and perennials (faster process)

climax community

a stable community (is ideal)

invasive species

• no natural predator and outcompetes the native species for resources

• can either be accidentally, environmentally or humanly (as a solution or not) introduced

disease/parasites

• harm a particular species and reduce biodiversity and food sources

• often are spread and carried by invasive species

• needs immediate identification and intervention

• ex: lantern flies

deforestation and urbanization

• lead to habitat fragmentation and lowered biodiversity

• can result in a loss of species due to increased competition between species and change species interaction and niches

climate change

• increased temperatures and evaporation

• drought conditions and more severe storms

• increased wildfires

• crops and producers are reduced

• organism adaptation and reproduction affected

• decreases biodiverity

el nino/la nina cycle

• el nino: equatorial surface temperature in the pacific rise and eastern winds blow weaker

• la nina: water is cooler and winds are stronger

• occurs every 3-5 years

• influences weather and storms

meteor impact

• usually broken up upon entry to Earth

• bring additional carbon sources to Earth

  • smoke and ash block the sun

volcanic eruptions

• usually around the equatorial

• immediate area negatively impacted:

  • destroys life/landscape

  • releases CO2 and SO2

• positive effects: distributes resources

• creates new land/islands

• caldera (where the lava comes out) can make new ecosystems

ecology

study of interactions between organisms and the environment

biodiversity

• relationship between distribution and abundance

  • healthy ecosystems are biodiverse

hierarchy of organization

• biosphere (entire Earth)

• biome/landscape (ecosystem seen as a larger group)

• ecosystem (community and abiotic factors)

• community (all living things in an area)

• population (number of organisms that are together)

• organism (living thing)

abiotic factors

non-living factors; earth’s climate

latitudinal variation and climate

• angle of sunlight affects intensity

• highest intensity/sunlight at the equator

• causes more diverse/abundant plant life

seasonality

• light and temperature increase steadily towards the poles

• high latitude caused by the tit of earth’s aor and its annual passage around the sun

• changing wind patterns affect ocean currents

animal migration (feeding and breeding)

result of seasonal environment changes

circadian rhythms influence plants and animals

• due to the position of the sun and magnetic fields

• 24 hour clock

plants have a daily/seasonal ____ with light

oscillation

climate change

• earth’s temp is rising

  • causes drier seasons, droughts, increased wildfires and co2 levels, and melting of ice caps

• affects the bioverse and changes ability to disperse and range

terrestrial biomes

on land

aquatic biomes

in water

climate disturbance influence on biomes

structure and distribution

terrestrial biomes and climates

• warmer and wetter = more abundant/diverse plant life

  • ex: tropical rainforest

• colder and dryer = less plant life and diversity

  • ex: arctic

climatograph

plots the annual mean temp and precipitation in a region

disturbances to biomes

• storms, fires, and human activity

• some dominant plants require disturbances

aquatic biomes

• stratified into zones/layers by light penetration, temp, and depth

  • upper photic zone: light available

  • aphotic zone: little light

    • makes up the pelagic zone with the photic zone

  • abyssal zone: depth of 2000-6000m

• benthic zone has (in)organic sediment at the bottom

  • community within: benthos

  • detritus: dead organic matter that falls from the productive surface water

marine biome

• [na] is about 3%

• largest: ocean

• covers about 75% of the earth’s surface

• impacts the biosphere

freshwater biome

• [na] is less than 1%

• affects soil and biotic components bordering the terrestrial biome

dispersal

movement of organisms away from centers of high population density or their area of origin

• contributes to the global distribution of organisms

non-native/invasive species

• intentionally or accidentally relocated

  • if successful: indicates that the potential is greater than the actual range

  • disrupt communities/ecosystems

population

• group of individuals of a specific species living in the same general area

  • described by their boundaries and size

  • affected by biotic and abiotic factors

density

number of individuals per unit area/volume

dispersion

pattern of spacing among individuals within the boundaries

population size can be estimated via sampling, using either the population index or the mark-recapture method

immigration

influx of new life from other areas or birth

emigration

moving out of an area or dying

demography

• study of the vital statistics of a population and how they change over time

  • death and birth rates are key measures

life tables

age-specific summary of survival patterns

survivorship curves

• graphic representation of a life table

  • type one: low death rates during and middle life and increased death rate with age

  • type two: constant death rate over the life span

  • type three: high death rate when young, decreases over time

individual population growth curves

idealized, unlimited environment; helps understand the capacity of a species

per-capital (birth-death) rate of increase

birth + immigration - death - leaving

population growth rate

change in pop size/time = birth - death

exponential growth

• idealized conditions (npt sustainable and describes some rebounding populations)

• roi is rmax

• results in a j-shaped curve

• dN/dT = rN

logistic model of growth

• slower growth due to the carrying capacity (k)

• k: maximum population size the environment can support

actual populations

fit general logistic patterns but need more time to settle

logistic model

tool for biologists to estimate the critical size below which populations may become extinct

k-selection

• selects life history traits that are sensitive to population density

  • k: carrying capacity

  • have fewer offspring but actually take care of them

r-selection

density independent selection, selects traits that maximize reproduction

density independent populations

• birth and death rates aren’t changing with population density

  • often due to climate and chemical conditions

density dependent populations

competition for resources, territorially, disease, predation, toxic waste

population dynamics

study biotic and abiotic factor that cause variations in pop size, stable pops hover around carrying capacity, most fluctuate

boom and bust cycles

predator and prey interaction, driven by predators

human population growth

no longer growing exponentially but increasing rapidly

age structure

graphs relative number of individuals at each age, indicates social and economic increase

community

groups of populations of various species living close enough for potential interaction

competitive exclusion

strong competition between two species; leads to elimination of a competing species

ecological niche

• sum of a species’ use of biotic and abiotic

• aka ecological role

• ecologically similar species can coexist in a community if there are one or more significant differences in their niches (resource partitioning)

predator adaptations

• claws, fangs, poison

• hunting-specific: mimicry and physical/chemical lures

prey adaptations

• hiding, fleeing, herds, spines,

• aposematic coloration: bright color warning to predators

• cryptic coloration: camouflage

• batesian mimicry: harmless species mimics harmful species

  • mullerian mimicry: two harmful species resemble eachother

herbivory

eats parts of plants or algae

first law of thermodynamics

• energy/mass cannot be created or destroyed

  • ecosystems absorb energy and release heat

autotrophs

• build molecules within cells

  • photosynthesis: light to energy

  • chemosynthesis: chemicals to energy

heterotrophs

must eat autotrophs and other heterotrophs

primary consumers

herbivores, eat producers

secondary consumers

carnivores, eat primary consumers

detritivores (decomposers)

• consume and degrade nonliving organic matter

  • decomposition contributes to recycled between trophic levels

primary production

• energy converted to chemical energy by autotrophs

  • limits length of food chains and webs

  • productive: tropical rain forests and coral reefs

food chains

link trophic levels from producers to top carnivores in a direct line (arrow goes in direction of energy passage)

food web

branching food chain with complex trophic interactions

limits on food chains

10% (on average) of energy stored in organic matter is converted for the next trophic level

production efficiency

• fraction of energy stored in food that’s not used for respiration

• (net secondary production)(100%)/assimilation of primary production

dominant species

highly abundant or important roles

keystone species

not necessarily most abundant, plays a key role in maintaining environment

trophic cascades

caused by a loss of a keystone species towards the top of a food web

foundation species

cause physical changes in the environment that affect community structure

tropical rainforest has the highest [] of species

conservation biology

seeks to preserve life via ecology, physiology, molecular biology, genetics, and evolutionary biology

genetic biodiversity

genetic variations within or between populations

species biodiversity

variety of species within an ecosystem or biosphere

community biodiversity

variety of ecosystems in a given region

endangered species

danger of becoming extinct

threatened species

likely to become endangered

extinction

• can be local or global

• local extinction can have a negative impact on the whole ecosystem

• loss of species = loss of unique genes and genetic diversity = loss of human benefits

ecosystem diversity

variety of ecosystems in the biosphere

immediate disturbance hypothesis

• diversity is maximized when disturbances are intermediate

• low diversity: dominance of one species, doesn’t allow others to thrive

• more frequent disruptions: more diversity, layering, and growing of the mature ecosystem

threats to biodiversity

habitat loss, introduced species, overharvesting, global change