Exam 2 Flashcards
Decomposition is
the chemical breakdown of chemical bonds formed during the construction of plant and animal tissue
Decomposition involves
respiration
Respiration
the release of energy originally fixed by photosynthesis, carbon dioxide, and water and ultimately the conversion of organic compounds into inorganic nutrients
when does decomposition happen quickly
warm wet places
How are heterotrophs decomposers
as they digest food, heterotrophs break down organic matter, alter it structurally and chemically, and release it partially in the form of waste products
microflora
most organisms that decompose material are bacterial and fungi
what are the dominant decomposers of dead animal matter
bacteria
what are the dominant decomposers of plants material
fungi
microbivores
feeding on bacteria and fungi
act as regulators of decomposition
what make up microbivores
protozoans, springtails, nematodes, larval forms of beetles
nutrient immobilization
the incorporation of mineral nutrients into microbial biomass
stages of decomposition
- early stages involve leaching and fragmentation
- detritivores oxidate organic compounds, releasing energy through respiration
- they degrade them into smaller and simpler products
- the release of organically bound nutrients into a inorganic form available to plants is mineralization
Mineralization
the release of organically bound nutrients into an inorganic form available to plants
Aphodius
dung beetle genus that develops eggs, larvae, and pupae within dung
process of decomposition on leaves
A. microbial decomposition of plant leaves can begin while the green leaves are still on the plants
B. living plant leaves produce exudates that support an abundance of surface microflora
C. when the leaves become senescent, the tissues are invaded by both bacteria and fungi, and decomposition accelerates
D. the action of litter feeders as millipedes and earthworms can increase exposed lead area 15 fold
E. fecal material from the detritivores is colonized by other microbes
rhizosphere
the soil region immediately surrounding the roots of living plants
rhizoplane
root surface itself
what conditions reduce or inhibit microbial activity
Dry and cold conditions
what are the most complex compounds found in nature
Lignin
what is lignin
fold into complex 3D shapes and slowest tissue to decompose
what is not required in the breakdown of animal flesh
specialized enzymes needed to digest cellulose
biogeochemical cycles
The cycles that nutrients move through in an ecosystem
sources of a gaseous cycle
atmosphere, ocean
sedimentary cycles
main reservoirs of nutrients are the soil and rocks of earth’s crust
describe nitrification
biological process which ammonia is oxidized to nitrate and nitrite
legumes
the most conspicuous of the nitrogen-fixing plants
mutualistic relationship with rhizobium
denitrification
nitrates are reduced to gaseous nitrogen by certain organisms to obtain oxygen
denitrifiers
fungi and bacteria Pseudomonas are facultative anaerobes
anaerobes
can use NO3 instead of O2 as hydrogen acceptor
anaerobes release
N2
proteins are broken down into ____ by bacteria and fungi
amino acids
amino acids are oxidized to
carbon dioxide, water, and ammonia, with a yield of energy
___ is absorbed directly by plant roots
ammonia
Ro=
Net reproductive rate (sum of lxmx)
mx
is the number of females born in each age cohort
dx
lx^1-1x^2
the number of dead
lx
the number of living
qx
dx/lx(1000) and is age specific mortality
Lx
(lx^1+lx^2+1)/2 average years lived by all individuals in each age category or cohort
Tx
sum of Lx the number of time units for all individuals to live from age x onward
ex
Tx/lx gives the number of time units that an individual can expect to live on having reached a cohort
Survivorship type 1
organisms that tend to live long lives (low death rate and high survivorship rate)
i.e. humans
Survivorship type 2
equal death in all stages of life i.e. rodents and birds
Survivorship type 3
high birth death rate but once reach maturity they live a long time with few predators i.e. fishes and seeds
density
the size of a population in relation to definite unit of space
crude density
the measure of the number of individuals per unit area
population
a group of organisms of the same species occupying a particular space at the same time
metapopulations
such separated populations interconnected by immigration
functional response
as prey density increases, each predator may take more prey or take them sooner
numerical response
predators may become more numerous though increased reproduction or immigration
type 1 functional response
predators of a given abundance capture food at a rate proportional to their encounter with prey items up to the point of satiation
type 2 functional response
predator efficiency rises to a point at which the predators response is slowed by handling time
type 3 functional response
the predator can switch to a more productive prey when the prey becomes more numerous
search image
a perceptual change in the ability of a predator to detect a familiar cryptic prey “it is easier to see patterns”
optimal diet
-a consumer should prefer the most profitable
-feed more selectively when profitable prey or food items are abundant
-include less profitable items in the diet when the most profitable foods are scarce
-ignore unprofitable items
Foraging efficiency
- concentrate foraging activity in the most productive patches
- stay with those patches until their profitability falls to a level equal to the average for the foraging area as a whole
- leave the patch once it has been reduced to a level of average productivity
- ignore patches of low productivity
marginal value theorem
this model predicts that foragers should remain in a rich food patch longer than in a poor one
leave all patches when they have been reduced to the same marginal value as the environment as a whole
expected energy budget rule
be risk-prone if the daily energy budget is negative; be risk-averse if it is positive
Keystone in tide pools
first sea stars and mussels are in the environment and then sea stars are removed and it is determined that without sea stars keeping the population in check, the mussel population will overflow
Aldo leopold
introduced conversation ecology
wrote “A sand county almanac” on land ethics
Gause’s principle
states that two species with identical ecological requirements cannot occupy the same environment
Joesph Grinnell’s principle
Two species of approximately the same food habits are not likely to remain long evenly balanced in numbers in the same region. One will crowd out the other.
Niche
the place occupied in its ecosystem, where it eats, what it eats, its foraging route, the season of its activity, and so on. A potential place where an species may have evolved
Gause competition experiments
used two species of Paramecium
P. aurelia and P. caudatum
Paramecium aurelia has a higher rate of increase than P. caudatum. When both were introduced into one tube containing a fixed amount of bacterial food, P. caudatum died out.
In another experiment, P. caudatum and P. bursaria and they both reached stability. PB was confined to feeding on the bottom of the tube and PC fed on bacteria suspended in solution.
desert temporary pools, dayton
found that tadpoles in areas with no predators had delayed metamorphosis (massive mortality)
pools with predation, density was reduced and metamorphosis occurred
Thomas park experiment
two species of beetles, Tribolium castaneum and T. confusum
he found that the outcome of competition between the two depended on temperature, humidity, and fluctuations in the total number of eggs, larva, and adults
Jim Brown
studied long term ecology of competition between Ants, and desert rodents for the grass seed resource
allelopathy
the chemical inhibition of one plant (or other organism) by another, due to the release into the environment of substances
phytotoxins kill the germinating seeds of many pants and reduce growth of seedlings
resource gradients theoretical #1
species A lives in an environment with a large gradient
B invades
A and B narrow their gradients and partially compete
C invades the space that is not being utilized at an optimal level (in between A and B)
resource gradient theoretical #2
C competes with both A and B on parts of the resource gradient
ABC narrow their range of reproduce use to optimum
Niche partitioning
each fed in a different part of the canopy and each was specialized behaviorally to forge in a somewhat different manner
G.E. Hutchinson
an organism’s niche consists of many physical and environmental variables, each of which can be considered a point in a multidimensional space (HYPERVOLUME)
niche compression
competition that results in the contraction of habitat rather than a change in the type of food or resources utilized
ecological release
niche expansion in response to reduced interspecific competition
niche shift
the adoption of changed behavioral and feeding patterns by two or more competing populations to reduce interspecific competition
fundamental niche
without competition
realized niche
with competition
niche width
narrow or broader
the wider the niche, the more generalized the species is
the narrower the niche, the more specific the species is
intraspecific competition
occurs when two or more individuals of the same species simultaneously demand use of a limited resource
scramble
competition for resources in short supply, all individuals have equal access to the resource and each attempts to get a part of it
contest
successful individuals usurp the resources and the unsuccessful are denied access to it
mechanisms of population regulation
dispersal
run
seek vacant habitat
which organisms disperse?
organisms in good condition with a high chance of survival
territoriality
a situation in which an individual animal or social group defends an exclusive area
not shared with rivals
philopatry
the tendency of an organism to stay in or habitually return to a particular area
general purpose territory (type 1)
feeding, mating, rearing of the young take place
mating territories (type 3)
pairing and mating
type 2
mating and nesting, feeding done elsewhere
why defend a territory
acquisition and protection of a resource ( food, reduction in predation)
attraction of mates
increased survival and best fit for that area
home range
an area over which an animal lives seasonally or throughout the year, defended, home ranges may overlap, not a fixed boundary
key factors
a biological or environmental condition associated with mortality that causes a major fluctuation in population size
life history
how individuals meet the costs and allocate them to reproduction
Dioecious
individual male/female plants
monoecious
bisexual
parthenogenesis
no reduction of gametes, asexual reproduction, in a single sex, production of a zygote from an unfertilized egg
lek behavior
is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, to entice visiting females which are surveying prospective partners with which to mate.
polyandry
the female mates with several different males and the male takes care of the offspring, females have to attract the mate
Niko Tinbergan
developed field of animal behavior
sticklebacks
Korand Lorenz
developed field of animal behavior
king Solomons rings
reproductive effort
the nature and amount of resource allocation to reproduction over a period of time, parental care is a big part
precocial
hatched or born in an advanced state and able to feed itself almost immediately.
altricial
the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth.
semelparous
species invest all their energy in growth, development, and energy storage, and then expend all energy into one massive suicidal reproductive effort
iteroparous
species produce fewer young at one time and repeat reproduction throughout their lifetime
altruistic
a relative taking care of offspring because it is helping to raise a copy of yourself = increasing reproductive success
as investment increases
offspring survival increases, and parental survival decreases
r- strategist
high reproductive rate
small body size
large number of offspring and little parental care
rapid development
short life span
k-strategist
delayed and repeated reproduction
larger body size and slower development
produce few young or seeds
parents care for young
at or near carrying capacity
plant defenses against herbivores
chemical- alkaloids
mimicry
structural defenses (thorns)
herbivore countermeasures
MFO (mixed function system) converts these chemicals into water-soluble molecules that can be eliminated by the excretory system
predator satiation
timing- max number of offspring are produced within a short time (not all can be eaten)
defenses of animal prey
speed
mimicry (two types)
chemical
armor and weapons
size
Heards
batesian
one species is toxic to eat and the look-a-likes are good to eat
mullerian
one unpalatable or toxic species mimics another (both dangerous)
attack-abatement effect
a predator is less likely to find prey where individuals are grouped than if an individual were distributed as solitary prey, group reduces chances of being taken
cannibalism
there are crowded conditions
stress (social ranking)
presence of vulnerable individuals (eggs, babies)
intraguild predation
eating a predator and a prey
lizards feed on web spiders and the insects that the spiders feed on
both predators and competitors
William Beebe
went half a mile down in the ocean
Jane Goodall
Ape lady
study behavior in apes
limited geographic distribution
Mammals with limited geographic
distribution risk becoming extinct
whenever their habitat is altered
or destroyed.
Low Reproductive Output
there is a balance between the probability of dying and the number of young a female must produce to help insure the survival of the species.
Edward O Wilson
Wrote the diversity of life
About loss of biodiversity around the world
mass extinction
An extinction event is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms
stochastic extinction
Small localized populations of a species are
more often subject to stochastic extinction
thin out population
extinction come about from normal
random changes within the population or
environment.
extinction
When deaths exceed births
and emigration exceeds
immigration, populations
decline.
reasons for nonconformity
- age structures are not stable
- birth rates and death rates are varied
- immigration and emigration are common to populations
carrying capacity
The number of
individual organisms the
resources of a given
area can support usually
through the most
unfavorable period of
the year.
exponential growth and crash
Exponential growth is not
biologically realistic: no
population can grow
indefinitely.
The environment is not
constant, and resources
such as food and space are
usually limited.
population growth
Populations change
constantly due to
interactions with the
environment.
