Ecology

Vocab

Biosphere

global ecosystem

sum of all ecosystems and landscapes

Biome

major life zones characterized by vegetation type (terrestrial) or physical enviornment (aquatic)

Biotic factors

living factors; anything organic (C+H)

other organisms that are part of an individuals environment

• predation/herbivory, pollinators, food resources, parasites/pathogens, competing organisms

abiotic factors

nonliving facotrs that influence the distribution and abundance of organisms

• temperature, water, oxygen, salinity, sunlight, rock, soil, pH

ecotones

area of integradation between 2 biomes

• can be wide or narrow

• shore, where prairie meets forest

inclination

the tilt of the Earth in the celestial orbit

23.5 degrees

reason for seasons

interspecific competition

individuals of different species compete for the same limited resources in an ecosystem

• negatively impacts both species’ growth, reproduction, and survival

• shapes niches and drives evolution

intraspecific competition

members of same species compete for limites resources necessary for survival and reproduction

• primary mechanism for population regulation

oligotrophic

nutrient-poor and oxygen-rich lakes

• lower surface area relative to depth

• may become more eutrophic over time as runoff adds nutrients and sediment

• lower decomposable organic matter in bottom sediment

Eutrophic lake

nutrient-rich and often depleted of O2 in deepert zone in summer

• higher decomposable organic material in bottom sediment

• high rates of decomposition in deeper layers → periodic O2 depletion

Desert

30 degrees N/S of Equator

low and unpredictable rainfall

temps vary seasonally and daily

low, widely scattered vegetation → C4 or CAM plants

nocturnal species with water conservation adaptations

Taiga/Northern coniferous forest

largest terrestrial biome

precipitation varies

cold winters, warm summers

cone-bearing trees that prevent snow build up

lower biodiversity

migratory birds, large mammals

affected by logging

climate

long-term prevailing weather conditions in an area

• seasonality, bodies of water, mountains

  • most significant influence on distribution of organisms on land

microclimate

localized patterns in climatic conditions

• environmental features can alter it

  • cast shade, change evaporation, impact wind, change temp

prairies (temperate grasslands)

highly seasonal precipitation (dry winter, wet summer)

cold winter, hot summer

grasses and forbs adapted for periodic droughts and fires

large grazing mammals and burrowing mammals

converted to farmland

temperate deciduous forest (temperate broadleaf forest)

high precipitation year-round

cool winter and hot summer

distinct vertical layers

• animals make use of layers

• epiphytes - plants growing on other plants (nonparasitic)

trees drop leave in autumn

hibernating animals and migratory birds

Tundra (Arctic/Alpine)

mid-high precipitation (depending on location)

very cold winters and cool summers

mostly herbaceous vegetation and dwarf shrubs

• permafrost limits large vegetation

large mammals and migratory birds

affected by oil/mineral extraction

estuaries

transition between river (fresh) and sea (salt)

• salinity varies spatially and with tides

• nutrients from river → one of most productive biomes

• network of channels, islands, levels, and mudflats

• saltmarsh grasses and algae

• worms, oysters, crabs, fish, water fowl

Benthic Zone

bottom of all aquatic zones (sea floor)

sand and sediment (organic/inorganic)

communities of organisms called benthos

• consume detritus (dead organic matter)

aphotic zone

lower region where little light penetrates

low levels of photosynthesis

abyssal zone at the very bottom (oceans)

photic zone

upper region of water with sufficient light for photosynthesis

littoral zone

shallow, well-lit water close to shore

• rooted and floating plants

limnetic zone

farther from shore and water too deep for rooted aquatic plants (lakes)

• phytoplankton and cyanobacteria

thermocline (metalimnion)

narrow layer of abrupt temperature change that separates more uniform upper layer from uniformly cold layer

epilimnion

top most layer of lake

• summer: warmest, most photosynthesis, most O2

• winter: coldest

hypolimnion

deepest layer of the lake

• summer: coldest, nutrient-rich, decomposition→O2 depleted

pelagic zone

photic+aphotic zone

open water

• mixed by wind and ocean currents (turnover in spring/fall)

• high O2 and low nutrient concentration

• phytoplankton

• zooplankotn, squid, fish, turtles, marine mammals

population

group of individuals in the same species living in the same area

• rely on the same resources and influenced by similar environmental factors

demography

study of vital statistics of populations and how they change over time

• birth, death, migration (immigration/emmigration)

  • focus on female

survivorship curve

plot of proportion or number in a cohort still alive at each age

Type 1 - low initial death rates

• large mammals

• few children, take good care of them

Type 2 - constant death rates

Type 3 - high initial death rates

• many children, little care

metapopulations

members of lacal populations are linked

• migration

• local population within it occupy discrete patches of suitable habitats

  • if one population goes extinct, patch may be colonized by other populations

source-sink metapopulations

quality of patches vary linked by dispersal

source - high-quality, B>D, net exporters

• rescues sink populations from extinction

sink - low-quality, D>B, net importers

generation time

time between two consecutive generations (birth of individual to birht of its offspring)

slow ←→ fast forms a continuum

helps estimate extinction

varies by size, environment, density

fecundity

potential to produce offspring

physiological maximum potential productive output

inversely related to parental care

different from fertility (actual number of offspring produced)

mortality

death rate in a population

altricial species

aniamls born or hatched underdeveloped

• helpless

• mature with the help of their parents

  • i.e. songbirds, dogs, marsupials

precocial species

young are relatively mobile from birth

• open eyes, hair/down, large brains, mobile

• ready to leave a few days from birth

  • i.e. horses, ducks, turtles

k-selected species

selection for traits beneficial at high densities

dnsity near carrying capacity

higher competition between individuals

i.e. mature trees in an old growth forest

r-selected species

selection for traits that maximize reproductive success in uncrowded environments (low densities)

lower competition

usually areas being recolonized

i.e. weeds growing in abandoned agricultural field

Allee effect

positive relationship between individual fitness and size of population

• small populations struggle to survive → extinction

  • mate limitation, cooperative defense, environmental conditioning, genetic drift

• strong correlation → spreads more slowly

Density dependent limiting factors

death/birth rates change as density changes

• regulates population

• limited resources, predation, disease, territoriality, intrinsic factors, toxic waste

density independent limiting factors

birth/death rate changes due to a factor unrelated to population density

i.e. weather events, pollution, natural disasters

inconsistent - not good at regulating population

semelparity

organism that undergo one-shot pattern of big-bang reproduction

i.e. salmon produce thousands of eggs in one reproductive opportunity before it dies

• one reproductive cycle before death

iteroparity

repeated reproduction

i.e. oak trees producing acorns every year

• multiple reproductive cycles

biotic potential

maximize reproductive capacity of a population under ideal environmental conditions

• peak birth rate, lowest mortality, unlimited resources

  • exponential growth w/o carrying capacity

carrying capacity

maximum population a particular environment can sustain

varies with abundance of limited resources

k

logistic growth curve

popualtion grwoth slows as population approaches carrying capacity

clumped spacing

individuals aggregated in patches

most common

mating behavior or increased effectiveness of predation or defense

i.e. fungi on a log

uniform spacing

individuals are evenly spaced

caused by direct interaction between individuals in a population

• inhibition of nearby growth or territoriality

i.e. nesting penguins

random spacing

unpredictable spacing

position is independent of other individuals

absence of strong attraction or repulsion among individuals

factors are constant across area

i.e. windblown dandelion seeds

exponential growth curve

population experiences ideal consitions and members are free to reproduce at physiological capacity

• increases at a constant proportion at each instant in time

• dN/dt=rN

life history

traits that affect an organism’s schedule of reproduction and survival

1) when reproduction begins

2) how often organism reproduces

3) how many offspring per reproduction cycle

community

group of populations of different species living in close enough proximity to interact

fundamental niche

niche potentially occupied by that species

realized niche

portion of fundamental niche a species actually occupies

because of competition, realized niche is often different than fundamental niche

resource partitionioning

differentiation of niches that enables similar species to coexist in a community

niche

set of biotic and abiotic resources an organism uses in its environment

character displacement

tendency for characteristics to diverge more in sympatric populations than allopatric species

predation

+/- interaction in which one species (predator) kills and eats the other (prey)

adaptation of both prey and predator are refined through natural selection

Batesian mimicry

palatable/harmless species mimics unpalatable/harmful species it is not closely related to

i.e. caterpillar that looks like venomous snake

caused by natural selection

Mullerian mimicry

2+ unpalatable species resemble each other

i.e. cuckoo bee and yellow jacket

symbiosis

any relationship between 2+ organisms that live closely together

species evolve together

i.e. commensalism, mutualism, parasitism

commensalism

+/0 interaction where one species benefits and the other is neither harmed nor benefited

i.e. flowers that need shade living in a forest with tall tress

proto-cooperation

+/+ interaction where both species benefit from the interaction but it is not required for either species’ survival

facultative mutulaism

i.e. rhino and bird

mutualism

+/+ interaction where both partners benefit

common in nature

can also cause negatives but benefits>costs

parasitism

+/- interaction where parasite derives nourishment from host organism which is harmed in the process

ectoparasite

parasite that feed on the external surface of a host

i.e. ticks, lice

endoparasite

parasite that live within the body of the host

i.e. tapeworms

parasitoids

insects that complete larval development within the body of another insect, eventually killing it, and is free living as an adult

larva in host → host dies

more like predator relationship

usually wasps

ecological succession

turnover of species in disturbed area

primary succession

life colonizes distrurbed area that was lifeless - no soil

• prokaryotes, protists, lichens, and mosses

  • make environment more favorable (sometimes)

secondary succession

colonize region that already had life that was cleared by disturbance that leaves soil intact

i.e. fire

keystone species

exert strong control on community structure by pivotal ecological role

not usually dominant - (most by biomass)

help maintain biodiversity and structure

biodiversity

entire variety of life

• genetic variation

• species variation

• ecosystem variation

aposematic coloration

warning coloration

cryptic coloration

camoflauge

herbivory

+/- interaction where plant is severly damaged

species richness

number of different species in community

relative abundance

percent each species represents among total individuals

species diversity

species richness + species abundance

trophic structure

structure of feeding relationships that determines energy flow

disturbance

an event that changes a community by removing organisms or altering resource availability

ecosystem

sum of all organisms living in a given area and the abiotic factors they interact with

biogeochemical cycles

nutrient cycle with biotic/abiotic factors

global - cycles of gasseous elements in the atmosphere or elements in water

local - heavier elements transported as dust and absorbed by plants

aquifers

underground water reserves

part of water cycle

nitrogen fixation

conversion of N2 to forms that can be used to synthesize organic nitrogen compound (NH3)

major pathway for nitrogen into the ecosystem

natural: bacteria, lightning, volcanoes

human: fertilizers, factories

nitrification

how nitrogen becomes usable for plants

Ammonia (NH3) →→ Nitrate (NO3-)

primary producer

autotrophs

supports all other life

photosynthesis or chemosythisis

plants, algae, prokaryotes

consumers

heterotrophs

levels above primary producer

herbivore

primary consumer

eats plants

decomposer

detriviores

consumers that get energy from detritus

convert organic matter from all trophic levels to inorganic compound usable by primary producers

detritus

nonliving organic matter

dead organisms, feces, fallen leaves, wood

fungi, prokaryotes, earth worms

food chain

transfer of energy upward from its source in plants and autotrophs (primary producer) → herbivores (primary consumer)→ carnivores (secondary, tertiary, and quaternary consumers)

trophic levels

position an organism occupies in a food chain

trophic cascade

simplified top-down model

N←P←H←C

Species turnover

replacement of species or change in community composition over time

photoautotrophs

use light energy to make organic materials

plants, algae

chemoautotrophs

use chemical energy to make organic materials

thermal vents

heterotrophs

depend directly or indirectly on the outputs of primary producers for their source of energy

consumers

detritivores

decomposers