14 Ecology Flashcards
Dispersion:
describes how individuals in a population are distributed; may be clumped, uniform, or
random.
Age structure:
description of the abundance of individuals of each age. Shape changes based on reproductive rate.
- Survivorship curves:
how mortality of individuals in a species varies during their lifetimes.
type I survivorship
most individuals survive to middle age and dies quicker after this age (human).
type II survivorship
length of survivorship is random (invertebrates-hydra).
Type III: survivorship
most individuals die young, with few surviving to reproductive age and beyond
(oysters). Typical of species that produce free-swimming larvae – the few that survive being eaten
become adults.
Biotic potential:
maximum growth rate under ideal conditions (unlimited resources and no
restrictions). The following factors contribute to biotic potential of a species: age at reproductive maturity, clutch size (# offspring produced at each reproduction), frequency of reproduction, reproductive lifetime,
survivorship of offspring to reproductive maturity.
Carrying capacity (K):
maximum number of individuals of a population that can be sustained by
habitat.
Limiting factors:
elements that prevent a population from reaching its biotic potential.
density dependent limiting factors
(limiting effect becomes more intense as population density increases-
competition for resources, spread of disease, parasites, predation, toxic effect of waste products, in some cases reproductive behavior abandoned when population attains high density) and
density independent limiting factors
(occur independently of density of population such as natural disasters or big temp changes).
growth rate of population
births-deaths/ N
Intrinsic rate:
when the reproductive rate (r) is maximum (biotic potential).
Exponential growth: occurs when
reproductive rate (r) is greater than zero. the population accumulates more new individuals per unit time when it’s larger, thus it curves to be more steep over time.
Logistic growth:
occurs when limiting factors restrict size of population to the carrying capacity
of habitat.
K is carrying capacity
– maximum population size that a particular environment can sustain.
K-selected population
– members have low reproductive rates and are roughly constant (at K) in size (humans). Competition among individuals tends to be stronger and there is a
limitation imposed by resources.
R – selected population
rapid exponential population growth, numerous offspring that are small, fast
maturation, little postnatal care needed. Generally found in rapidly changing environments affected by density independent factors. growth curves that are exponential. Population densities
are well below carrying capacity, little competition faced.
opportunistic species
species that quickly invade habitat and then die
Bacterial Growth: 4 phases
- lag phase: bacteria adapt and mature to eco
- log phase (exponential) doubling here in size
- stationary phase: growth rate= death rate from limiting factor
- death phase: DIE
Shannon diversity index
higher means more diverse population
Competitive exclusion principle (Gause’s principle):
two species compete for exactly the same
resources (or occupy the same niche), one is likely to be more successful (no two species can sustain
coexistence if they occupy the same niche).
Resource partitioning:
two species occupy same niche but pursue slightly different resources or
securing their resources in different ways, individuals minimize competition and maximize success
(multiple species-slightly different niches).
Character displacement (niche shift):
a result of resource partitioning, certain traits allow for more
success in obtaining resources in their partitions reduces competition divergence of features (character displacement).
Realized niche:
niche that an organism occupies in absence of competing species is its fundamental
niche. When competitors are present, one/both species may be able to coexist by occupying their realized
niches
Parasitoid
an insect that lays its eggs on host (insect or spider). After eggs hatch, larvae obtain
nourishment by consuming host’s tissues. Host eventually dies, but not until larvae complete
development and begin pupation.
Granivores
seed eaters
browser
eat leaves
Commensalism
one benefits, the other is unaffected
Mutualism
both orgs benefit
Parasitism
benefits at the expense of the host; bacteria and fungi; live with
minimum expenditure of energy
Facilitation
species have positive effects (+/+ or 0/+) on the survival and reproduction of another
species w/out necessarily living in the direct and intimate contact of symbiosis.
Saprophytism
decompose dead organic matter externally and absorb nutrients
*scavengers directly feed
Zoonotic pathogens
transferred from other
animals to humans.
Vectors
intermediate species of infxns.
Interference competition
directly between individuals via aggression. individuals can’t establish on habitat. can happen through allelopathy
allelopathy
the production of biochemical by an organism that influences the
growth/survival/reproduction of other organisms).
Exploitation competition
occurs indirectly through
depletion of a common resource.
Apparent competition
occurs between 2 species preyed upon by the same predator
Arthropods regulate water by
secreting solid uric crystals
Cold-blooded (poikilothermic) temp regulation
–vast majority of plants and animals; body temp. is close
to that of surroundings, so metabolism is radically affected by environmental temp.
Warm-blooded (homeothermic)
make use of heat produced by respiration; physical
adaptations like fat, hair, and feathers retard heat loss (Ex: mammals and birds)
Coevolution:
evolution of one species in response to new adaptation that appear in another species.
- Secondary compounds:
toxic chemicals produced in plants that discourage would-be herbivores
- Aposematic coloration (warning coloration):
conspicuous pattern or coloration of animals that warns
predators that they sting, bite, taste bad, poisonous, or are otherwise to be avoided.
Mimicry:
occurs when two or more species resemble one another in appearance.
Mullerian mimicry:
occurs when several animals, all with some special defense mechanism,
share the same coloration
Batesian mimicry:
occurs when animal without any special defense mechanism mimics the
coloration of an animal that does possess a defense.
(blowout).
catastrophic event wiping pop
Substrate texture:
changes from solid to rock or something
- Primary succession:
substrates that never previously supported living things like lava and then lichens come, then water, then soil et
- then r selected species
- then k selected
secondary succession
had life, had a disaster, then life came back
dominant species
species in a community that is the most abundant or collectively has the
highest biomass.
keystone species
usually abundant but exert a strong control on community
structure not by high quantity but through their pivotal ecological role.
Ecosystem engineers
foundation species dramatically alter their physical environment.
water cycle
reservoir to assimilation into plants and animals. then release from transpiration and decomposition
carbon cycle
reservoir then plant uses co2 (assimilation) then release when stuff dies
nitrogen cycle
nitrogen reservoir from atm. then assimilation by plants (nitrification) then
phosphorus cycle
reservoir is sediment. then assimilation by plants, then release when they die
Tropical rain forest:
high (but stable) temperature and humidity, heavy rainfall, (tall trees with branch
at tops
little light to enter). Most diverse biome.
Epiphytes
plants that grow on other plants (like vines)
Savannas:
tropical grasslands with scattered trees. similar to tropics in that they have high temperature, but they get very little rainfall (25 inch). this be Australia and africa. very fiery
ungulates,
large hooved plant-eating mammals like giraffes.
Temperate grasslands:
receive less water (+ uneven seasonal occurrence of rainfaill) and are subject
to lower temperatures than savannas (e.g. north American prairie). Grassland soils are among the most
fertile in the world.
Temperate deciduous forests:
warm summers, cold winters, and moderate precipitation. Large
deciduous trees shed leaves during winter. Soil is rich due to leaf shed.
*have vertical stratification
Vertical stratification:
plants+animals live on ground, low branches, and treetops. Principal mammals hibernate through cold
winter.
Temperate coniferous:
cold (sometimes dry) forests; vegetation has evolved adaptations to conserve
water (needle leaves). Some temperate coniferous forests aren’t dry and receive precipitation via rainfall.
Cold, but warmer than taigas.
Deserts:
hot and dry; most extreme temp fluctuations (hot day, cold night); growth of annual plants
is limited to short period following rare rain, plants and animals adapt to conserve as much water as
possible (urinate infrequently, cacti spines, etc)
Taigas:
south of the tundra. Coniferous forests (and trees with needles for leaves: spruce, fir, pine).
Very long cold winters and low precipitation in form of heavy snow. Largest terrestrial biome.
Tundras:
cold winters (ground freezes), top layer thaws during summer support minimal vegetation
(moss, lichen, low growing shrubs, grasses - treeless). but deeper soil (permafrost) remains permanently
frozen. Very little rainfall that can’t penetrate frozen ground. Short growing season.
Chaparral:
terrestrial biome along California coastline characterized by wet winters, dry summers, scattered vegetation (dense, spiny shrubs) – California fires happen here
polar region
frozen
Fresh water biomes:
ponds, lakes, streams, and rivers. Hypotonic to organisms, affected by
climate/weather variations.
estuaries
(where oceans and river meet),
intertidal zones
(where ocean meet land),
continental shelves/littoral zone
(shallow oceans bordering continents),
benthic zone
lowest layer of a body of water, including
sediment surface and sub-surface layers. In ocean water (deep) light doesn’t penetrate; most organisms
are scavengers and detritivores.
pelagic,
middle layer of water
Epiplagic, mesopelagic, bathypelagic, abyssopelagic, hadopelagic
Epiplagic
(surface layer of water, only photic zone since
enough light for penetration, nearly all primary production of ocean occurs here)
mesopelagic
(not enough light for photosynthesis, minimal oxygen)
bathypelagic
(pitch black, no plant life, most organisms here consume detritus that comes down from above)
abyssopelagic
(cold, high pressure, most species have no eyes due to lack of light)
hadopelagic
(most life here exists in hydrothermal vents).
turnover
In autumn and spring, oxygenated water from surface goes to the
bottom and nutrients from the bottom go to the top.
Eutrophication
process of nutrient enrichment in lakes and subsequent
increase in biomass
Critical load
amount of added nutrient (usually N or P) that can be absorbed by plants w/out
damaging ecosystem integrity.
Biological augmentation:
using
organisms to add essential materials to degraded ecosystem
bioremediation
using organisms to detoxify a polluted ecosystem
Extinction vortex:
small population size
inbreeding, genetic drift have significant effect loss of genetic variability
reduced fitness ↓ survival. To avoid this a population must sustain itself at the minimum viable population (even lower!)
rain shadows
areas of dry land that form on the leeward side (downwind) of a high mountain. Rain approaches mountain,
surrounding air becomes cooler due point eventually reached precipitation occurs as cloud gains precipitation, continues to rain towards peak cloud begins to descend leeway side of mountain decrease in elevation air temperature increases precipitation decreases rain shadow is dry (desert biome). Can occur in the high mountains of Europe and even the Andes of South America.
