Ecology Exam 3 Flashcards
The outcome of a predator-prey interaction depends on
reproductive rates of predator and prey, adaptive capacity of predators to respond to increase in prey density, carrying capacity of prey in absence of predation
kinds of predation on plants and their impact (+/-)
parasitism (-), defoliation (-), consumption of fruit/nuts (+/-)
parasitism always has a negative impact on ___
plant fitness
positive impacts of predation?
moderate grazing can promote grass growth, moderate fruit/nut eating spreads seeds
chemical defenses against predation
accumulate secondary compounds (terpenes, phenolics, resins, alkaloids, tannins) induced by scratching or biting from insects
mimicry defense
uncommon, mimic plants that are inedible, mimicry of crops by weeds
structural defense
least costly, tough leaves, spines, leaf hairs
predator satiation
timing of reproduction so predators can’t consume all seeds, masting
other example of defense shown by lithops
camouflage
chemical defense (animal)
warning odors, repellants, poisons
what is the skunks defense
produce smelly spray to repel predators, produced in two glands by the tail, long-lasting smell, has 2 other functions
what is the milkweed defense
cardenolide aglycones and cardiac glycosides cause illness in birds and other animals
mimicry in animals
Mimicry is a defense strategy that many animals use to
avoid predation by mimicking animals that have a bad taste,
obnoxious secretion, or painful bite or sting, usually have bright colors or bold markings
mullerian mimicry
two unrelated, dangerous species develop similar appearances as a shared protective device
batesian mimicry
a harmless animal mimics a dangerous animals to avoid predation
cryptic coloration defense
Animals can use patterns, shapes, postures, movements and
behaviors that make them less visible to predators
other forms of defense for animals
armor/weapons and behavioral (alarm call, distraction, groups, moment-of-truth defense)
predator satiation in animals
no need for costly defenses, produce more than predator can consume. cicada example
predator offense methods
ambush, trapping, pursuing
up/down side of ambush technique
low reward, low energy cost
up/down side of pursuit
time saving, high reward, very energy costly
coevolution
Reciprocal selection pressure on interacting populations, cycle of adaptation and counteradaptation
parasites
Organisms living on the tissue of their host, often reduce fitness of host but do not kill
parasitoids
Organisms living in their host and killing it, usually insects
ectoparasites
live on outside of host (ticks and fleas)
endoparasites
live on inside of host (bacteria, tapeworms)
macroparasites example
lungworms, cowbird in barn swallow nest
microparasites example
bacteria and viruses, nematode
two types of plant parasites
holoparasite, hemiparasite
what is a holoparasite
Lacks chlorophyll and are totally dependent on other
plants for everything
hemiparasite
Can photosynthesize. Do not have root system and
rely on other plants for water and nutrient supply
holoparasites example
Rafflesia arnoldii – the world’s largest flower in Indonesia
hemiparasite example
mistletoe
example of size effect of parasites
Swift reduction in density of American chestnut
in North Carolina
cellular defense reactions in response to parasites
Common in insect larvae as a defense against parasitoids.
Parasitoid eggs are encapsulated in a tough case and become
inviable.
immune responses to parasites in vertebrates
Development of immune systems. Phagocytes
Defensive displays or maneuvers to deter parasites.
Gypsy moth pupae can spin violently within their cocoons
so parasitoids can not lay eggs.
Grooming and preening behavior in response to parasites
Common in mammals & birds to remove ectoparasites.
abnormal growths in response to parasites
gall, plant galls on leaves
symbiosis
long-term, intimate relationship between two species
two types of symbiosis
obligate (cannot survive w/o each other), facultative (can lead separate lives)
mutualism
an association between species that benefits both
example of mutualism as symbiotic or not
Lichen fungi and lichen algae are only found together - symbiotic.
Plants and pollinators are only in contact when the pollinator is
feeding - not symbiotic
plants and mycorrhizae mutualism
very common and important, plants get minerals from absorptive power of fungi and fungi get photosynthates from plants
absorptive power of fungi
hyphae of fungi increase absorptive area of roots
ectomycorrhizae
fungi may remain outside of plants roots
endomycorrhizae
fungi may penetrate root
plants and nitrogen-fixing bacteria
important mutualism, presence of bacteria causes plant roots to nodulate, legumes
fungi and algae in lichens (obligate mutualism)
many fungi are lichenized, each needs a particular species of algae but each algae species usually can form a lichen with several
different species of fungi… fungi gets photosynthates from algae and algae get minerals and dessication protection and dispersal from fungi
what does the pollinator get in pollination mutualism
Food (nectar, pollen- high energy or high protein food)
Mating advantage - some bees get scent molecules
Nesting materials - some bees get wax for their nests
what does the flowering plant get in pollinator mutualism
Efficiency of pollen transfer (compared to wind)
Mixing of pollen from many plants and prevention of
inbreeding
diffuse systems (pollination mutualism)
Many flowers are visited by more that one species of
animals, all of which may act as pollinators. Common
highly coevolved relationship (tight relationship)
orchids and pollinators, figs and wasps, yucca and yucca moth
orchids and pollinators
many orchids are pollinated by a single species of insect, flowers of orchids are shaped so only corrrect insect can get to nectar and carry pollen
figs and wasps
figs produce flowers in capsules and each figs species has its own species of wasps. female wasp lives all of its larval life in fig and only spends enough time out of one as an adult to disperse to the next fig, males never leave the fig in which they hatched, grew as larvae,
and pupated. Males fertilize females in same fig and die.
yucca and yucca mouth
Each species of yucca is pollinated by a single specie of moth
which lives only on the species of yucca that it pollinates.
defense mutualisms
One species gets food and/or shelter from another species.
Other partner gets protection from being eaten.
ant-acacia system (defense mutualism)
bull thorn acacia provides a place for ants to live in base of thorn and food for ants in form of special extension of leaves called betsian bodies
ants are aggressive and attack almost anything that comes into contact with acacia plant
ant and aphid mutualism (defense mutualism)
aphids provide honeydew for ants, ants act like ranchers and move aphids on plants to maximize honeydew production and shelter aphid eggs in nests during winter
dispersal mutualisms - ant and pacific bleeding heart
bleeding heart provides oil rich appendages (elaiosomes) for ants, ants help disperse seeds
*also between ants and trilliums
dispersal mutualisms - ant and fungus (obligate mutualism)
leaf cutter ants cut pieces of vegetation to take back to their nests, chew the plants to a mush for fungus to grow on, ants eat the fungus, fungus grows best at temp in center of nest.. ant removes competing fungi and bacteria.
when queens leave and start new nest they bring fungus with them and start new farm there
what is a community?
Plant and animal populations interacting directly and
indirectly with each other
what is a guild?
Groups of organisms that utilize resources in a similar manner.
christen raunkiaer
classified plants based on perennating tissue location above the ground
therophytes
annuals survive unfavorable periods as seeds. complete life cycle from seed to seed in one season
ex: winter wheat
geo/cryptophytes
buds buried in the ground on a bulb or rhizome
ex: tulip
hemicryptophytes
perennial shoots or bulbs close to the surface of the ground, often covered with litter
ex: iris
chamaephytes
perennial shoots or bulbs on the surface of the ground to about 25 cm above surface
ex: creeping juniper
phanerophytes
perennial buds carried well up in the air, above 25 cm (trees, shrubs, vines)
epiphytes
plants growing on other plants, roots up in the air
helophyte
bulbs/roots in water soil
ex: water lily
hydrophyte
actually grows on water.. no connection to soil below
ex: water hyacinth
halophyte
plants that can tolerate high salinity
ex: salt bush
species diversity
distribution of species within a community
diversity index
simpson index of diversity: Hd
shannon index of diversity: Hs
brillouin index of diversity: Hb
4 effects of population interactions on community structures
competition, predation, parasitism and mutualism
competition examples
zebra mussels, multiflora rose
predation examples
wild pigs with dingoes (without dingoes, more young pigs survive)
parasitism examples
dutch elm disease caused by fungus and spread by beetles
mutualism example
seeds of dodo tree can’t germinate without passing through dodo bird
communities are classified based on
the most predominant species (deciduous forests: maple, oak, shagbark hickory) or how they get their energy
autotrophic community
a community consisting of photosynthetic plants
heterotrophic community
A community consisting of
heterotrophic organisms
what is zonation
spatial variation in community structure
what is succession
temporal variation in community structure
early successional species
dominant species in early stages of succession, high growth rates, small in size, high degree of dispersal, high rates of population growth
late successional species
dominant species in late stages on succession, lower growth rates, larger in size, lower degree of dispersal, lower pop growth rates
early successional species example
populus tremuloides (pioneer species)
late successional species example
sugar maple
primary, secondary succession
development of early to late successional species in an area.. primary = beach, secondary = burned area
climax community
stable end community of succession, equilibrium with biotic and abiotic environment
climax community example
tropical forests in panama
three special successions
cyclic replacement, autosuccession, hydrosere
cyclic replacement
sequence of seral stages is interrupted by imposition of disturbance, community never arrives at climax
autosuccession
self-replacing nature of the vegetation
hydrosere
succession in wet habitats
four premises for community dynamics
The fundamental niche of a species is the primary constraint on its distribution and abundance
species vary in their fundamental niches
environmental conditions change in time and space
fundamental niche is modified by species interactions
cattail experiment at MSU
two species of cattails grown at varying water depths both together and separate. shows realized niche of both and their different needs
autogenic environmental change
Changes in environmental conditions brought about by
the organisms themselves, ex: change in light thru succession/growth
allogenic environmental change
Changes in environmental conditions that are purely abiotic, ex: temperature, soil properties, precipitation
can affect zonation and succession
succession and species diversity
succession can facilitate emergence of new species. local disturbances to environment can disrupt speciation
herbivores: direct effect
herbivores are selective. Favors the organisms herbivores don’t like
affect succession: predate on early succession species, hasten succession but predate on late succession species, slow succession
what is the ecosystem
all the organisms and their environment
energy
the ability to do work (in Joules)
first law of thermodynamics
total amount of E in the universe stays constant, E can’t be created or destroyed but can be transformed
second law of thermodynamics
spontaneous direction of energy flow is from high-quality to low-quality forms, with energy conversion often loss of waste energy as heat
primary production
production of biomass by photosynthetic autotrophs
gross primary production
all the energy is assimilated in photosynthesis
net primary production
energy that remains after respiration (R)
net primary production is dependent on
environmental factors like precipitation and temperature
swr, rwr, lwr
shoot weight ratio, root weight ratio, leaf weight ratio
R/S tends to be high when
nutrients are limited
R/S tends to be low when
light is limited
plants translocate carbs and nutrients to roots and stems before
senescence
secondary production
production by heterotrophs, it depends on the quantity, quality and availability of NPP as a source of energy
assimilation efficiency (A/I)
ratio of assimilation to consumption, it measures efficiency of the consumer at extracting energy from the food it consumes
average A/I for homeotherms and poikilotherms
70% homeo, 40% poikilo
