Biology

ecology
scientific study of relationships between organisms and environment
environment factors(ecosystem) include
biotic and abiotic
differences between resources and conditions
resources- can be consumed and competed ex. food, water, and mates
conditions- cannot be consumed but influence organisms ex.temperature, day length, humidity
ecology was coined by
Ernst Haeckel in 1866
oikos is
household of nature
who laid the foundation of biogeography
alexander von humboldt
ecosystem is
an environment which organisms carry out their struggle for survive
a collection of parts that function as a integrated whole
observational study is
mensurative
field experiment is
manipulative and difficult to control other factors
explanatory variable is
independent variable
response variable is
dependent variable
replication is required because
to reach accuracy in results
data can be
categorical and numerical
categorical data are
unordered categories
only two categories exist called
binary
numerical data include
discrete and continuous
histogram is
relationship between categorical(x) and numerical(y) data which is continuous
whats a scatter plot
relationship between two independent continuous variables
whats community
a group of species that occupy a given area and interact each other either direct or indirect
species richness is
count of the number of species within the community
relative abundance is
the percentage each species contributes to the total number of individuals of all species
the simplest measure if diversity is
species richness
species accumulation curve
number of samples on x axis
species richness on y axis
species rarefaction curve is
to improve the precision of richness estimates
a common method for comparing species richness and abundance is
rank abundance curve or
whittaker plot
relative abundance on y axis
rank on x axis
dominants are
a single of few species predominate within a community
diversity indice is
a way to quantify the relationship between species number and relative abundance
range from 1 to species richness
species evenness is
to determine the equitable distribution of species in a community
range from 0 to 1
biogeography is
the study of spatial or biogeographical distribution of organisms, both past and present
differences between historical and ecological biogeography
historical-origin, dispersal, extinction of groups
ecological-distribution of contemporary organisms
biomes are
large scale regions describing spatial variation in plant growth forms and climate
ecoregions are
small scale regions describing spatial variation in plant growth forms and climate
biogeographic regions
large scale regions describing spatial variation in species composition of animals, plants and microbes
relationship between annual precipitation and temperature
mean annual precipitation decrease with declining of mean annual temperature
relationship between temperature and regions
temperature decreases from equator to the poles, while seasonal variation in temperature increase
what classifies terrestrial biomes
trees, shrubs and grasses
two types of leaves
deciduous-live for a single year or a growing season
evergreen-lives beyond a year
characters of tropical rain forest
dominated by broadleaf evergreen plants
between N10 and S10
relatively medium temperature and high precipitation
savannah is
a range of vegetation types in the drier tropics and subtropics by a ground cover of grasses with scattered trees and shrubs
characters of savannah
relatively medium temperature and distinct seasonality in precipitation and large inter-annual variation in total precipitation
plants in savannah are
grasses and shrubs
fire-adapted and short lived
precipitation control yearly cycle of plants activity and productivity
grasslands are
regions where rainfall is between 25 and 80
occur in mid-latitudes in mid-continental regions where precipitation is reduced
deserts are
acid regions which occupy 25 to 35 percent of earth’s landmass
lack rainfall
located far inland or mountain barriers
shrubland is
a plant community in which the shrub growth is dominant or co-dominant
temperate deciduous forests are
forests dominated by broadleaf deciduous trees
low temperature
conifer forests are
found in a broad region across the northern hemisphere on mountain regions
lower temperatures limit growing season to a few months each year
permafrost is
the perennially frozen subsurface that develops where the ground temperature remain below 0
tundra us
a frozen plain thats is located at the highest latitudes of the northern hemisphere
two types of tundra sub-biomes are
polar grasslands-up to 100 percent plant cover and wet to moist soils
polar desert- less than 5 percent plant cover and dry soil
a treeline is
the geographic limit beyond which forest doesn’t grow
the geographical distribution of animals
the world’s zoogeographic regions was covered by
Alfred R. Wallace
zoo and photo geographic regions
zoogeographic regions- spatial patterns of animal species composition
phytogeographic regions- spatial patterns of plant species composition
spatial patterns of diversity
decline as you move from equator to two sides of the earth
why does species richness decline from the equator?
tropical are older
less affected by glaciations
climate more stable
more resources
more habitat
more lineages have evolved in and adapted to tropical conditions
actual evapotranspiration is
flux of water from terrestrial surface to the atmosphere through evaporation and transpiration
most correlates with species richness
by david currie and v. paquin
animal diversity is linked to plant diversity as
plants provide food and habitat
mountain regions
support greater species diversity but less species richness as elevation goes higher
two explanations for spatial patterns of diversity
contemporary hypotheses
-productivity/energy
-habitat heterogeneity by david
historical and evolutionary
-niche conservatism
-climate stability by wiens jj
succession is
the gradual and directional change in community structure through time
sere is
the sequence of communities from grass to shrub to forest
sere stage is
the each change of the stage
early successional species are
also called pioneer species and are usually characterized by high growth rate, smaller size, high dispersal and high rate per capital growth i.e r-strategist
late successional species are
lower growth, dispersal and colonization rate, larger and longer lived i.e K-strategist
a successional experiment is called
hubbard brook experimental forest
primary succession occurs
on a site previously unoccupied by a community i.e sand, rocks
secondary succession occurs
on perviously occupied sites after disturbance
grasses are
the most successful pioneering plants
toposequence
used to monitor temporal change using a spatial gradient
chronosequence
monitor temporal change in forest stands using similar adjacent sites
who developed the concept of ecological succession
e. warming and h. cowles
monoclimax hypothesis
the community is a highly integrated superorganism
paleoecology is
the study of the distribution and abundance of an ancient organisms and their relationship to the environment
a unifying framework is
-selection
-speciation
-drift
-dispersal by m. vellend
metapopulations is
a population consisting of many local populations
separate populations interconnected by the movement of individuals
4 necessary conditions for metapopulation
-suitable habitat
-largest populations may have rick of extinction
-habitat patches must not be too isolated to prevent recolonization after local extinction
-local populations are not synchronized by lc hanski
two sets of spatial scales
-local or within-patch scale, individuals interact with each other
-metapopulation or regional scale, governed by local population interactions
colonization is
the movement of individuals into a patch
metapopulation is
a balance between local extinction and colonization
rescue effect is
the increase in population size that occurs with an increasing rate of immigration in order to decrease extinction rate
source populations
maintain a positive growth may permit sink population to exist
sink populations
cannot support positive growth
as patch size increase
interior increase clearly but edge does not
interior species
need conditions of interior habitats and stay away from abrupt changes may in or decrease with patch size
patch increase, interior increase, edge decrease
area sensitive species
can use both edge and interior, occurrence is not affected by patch size
relaxation effect(extinction debt) is
refer to a delayed loss of species over time
the equilibrium theory of island biogeography has been applied by
E,O wilson and R. macarthur
study of terrestrial landscapes
number of species colonize in are equilibrium to species that are extincted
species turnover rate is
the rate that one species is lost and a replacement species is gained at equilibrium
S (equilibrium species richness) is achieved when
immigration rate= extinction rate
affected by distance from the mainland
the size of the island
corridors
connect similar patches of habitat
they are habitats as well
metapopulations
predict the incidence of a species on a given habitat patch
metacommunities
predict the expected number of species
the first experimental test of the theory is island biogeography was preformed by
EO wilson’s student daniel simberloff
niche as n-dimensional hyper volume was described by
G.E hutchinson
fundamental niche is
the full range of conditions and resources under which it can survive and reproduce
realized niche is
the portion of the fundamental niche that the species actually exploits
niche breadth is
the tolerance range of environmental conditions
niche breadth may be
generalists or specialists or maybe both
niche compression is
the reduction of niche breadth in response to a competing species
if a competitor is removed the affected species will experience
competitive release
niche differentiation is
differences in the range of resources used or environmental tolerance
resource partitioning
similar species coexist by partitioning available resources by robert macauther
limited similarity is
ecological similar species coexist only if they have evolved sufficient differences in appearance to allow niche seperation by G.E hutchinson
character displacement
involves a shift i feeding niche that subsequently affects a species morphology, behaviour or physiology
amensalism is
negative for one and 0 for the other
darwin contribute to
abiotic and biotic factors
wallace contribute to
abiotic factors
exploitation is
competition occurs when species indirectly interact with one another but affect the availability of shared resources
interference is
species directly interact and prevent others from occupying a habitat or accessing resources within it
six types of interspecific competitive interactions are
consumption, pre-emption, overgrowth, chemical interaction, territorial, encounter
asymmetric competition is
one individual is much more negatively affected than the other
diffuse competition is
individuals of many species compete and the impacts on an individual reflects effects of its interactions with individuals of many species
diffuse competition is
competition by a constellation of species by McArthur
competitions by two species enable coexistance of a third species by JP
complete competitors are
two species that live in the same place and have the same ecological requirements
competitive exclusion principle states
that complete competitors cannot coexist
factors affect interspecific competition
temperature ph
limiting resources
resources partitioning
competitive exclusion is rare because
conditions do not remain constant
competitive hierarchy among species is not absolute, they might be tradeoffs or shift in response to change in abiotic conditions
territorial competitions commonly in
birds
chemical territorially called
allelopathy is commonly in plants
food chain is
a descriptive diagram that represents the flow of energy from prey to predator
basal species are
feed on no other species but are fed upon others
intermediate species are
feed on other species and they themselves are prey of other species
autotrophs are
primary producers
heterotrophs are
consumers
connectance is
the proportion of all possible links
food webs indicate
indirect species interaction
two controls
top-down: higher tropical levels regulate abundance and productivity of primary producers
bottom-up: primary producers regulate the populations of higher tropical levels
tropic cascades are
the propagation of indirect effects between non adjacent trophic levels in a food chain or food web
keystone species has
a disproportionate impact on the community relative to its abundance
removal of keystone species changes the structure of community results in loss
bioengineers are
keystone species which can modify their habitats
-beavers can alter heterogeneity and local hydrology in order to build dam
-ants can alter physical and chemical structure of the soil by digging holes and bringing food to nests
mutualism can be characterized by
-benefits received
-degree if dependency
-degree of specificity
-duration of intimacy
mutualism benefits
-provision of energy
-protection from predators, parasites or herbivores
-reduced competiiton
-dispersal of gambits or offspring
level of dependancy
-obligate: cannot survive or reproduce without the mutualistic interaction
-facultative: can survive without the interaction
degree of specificity
-specialists: species specific interactions
-generalists: association with a wide diversity of mutualistic partners
symbiosis is
the intimate and protracted association between two or more organisms of different species
non-symbiotic mutualism, two organisms are
facultative
-pollination
-ants dispersal seeds
nectivores are
species which visit plants to exploit a source of food and pick up pollen carry it to the next plant
myrmecochores are
plants that produce seeds with an ant-attracting food on the seed coat(elaiosome)
frugivores are
fruit eating animals that eat only the tissue around the seed
predation is
consumption of one living organism by another
heterotrophs are
carnivore, omnivore and herbivore
cannibalism is
intraspecific predation
seed predators ann planktivires are
true predators
rodents and whale sharks
parasites feed on
prey organism while its still alive
parasitoids
lay eggs on host and feed on host, slowly killing the host
coloration include
cryptic colouration
object resemblance which among insects
flashing colouration which alarm and distraction
apoematism-warming colouration
batesian mimicry is
when an prey species mimics the predator species
butterfly snake
mullerian mimicry is
similar colour pattern shared by many unpalatable or venomous species
two classes of defence
constitutive defence: are fixed features of organisms warming colouration, defence shell
induced defence: are bought by the presence or action of predators alarm pheromones kamikaze ants
types of herbivory
grazers which eat grasses on the ground
browsers which eat leaves, stems and bark from plants
plants also have
structure defence
chemical defence
secondary metabolites are
chemicals produced by plants that either reduce digestion or deter herbivore from eating
-nitrogen based
-terpenoids variety of essential oils
-phenolics aromatic compounds including tannins and lignin
quantitative inhibitors are
secondary compounds produced by plants to reduce digestibility
first law of thermodynamics
total amount of energy remains constant
energy cannot be created/destroy, can only be transformed and transferred
second law of thermodynamics
every transformation, some useful energy is lost
living systems are open and rely on solar energy inputs to counteract entropy
primary productivity
autotrophs fix chemical energy into organic matter through photosynthesis
Net pp =
Gross pp-respriation
Gpp is
rate of energy assimilated per unit area per unit time
scb is
standing crop biomass
difference in time+death+consumption
residence time is
time that energy persists in a trophic level
biomass accumulation ratio is
BAR=scb/npp
factors affect npp
water temperature light actual evapotranspiration have positive affect
land ecosystems often limited by
nitrogen
in aquatic ecosystems often limited by
light
compensation depth is
gpp=r npp=0
npp=gpp-r
sea water phytoplankton is limited by
nitrogen and then iron
in lakes is limited by
phosphorous
root shoot ration
increases as moisture decreases
decreases transpiration and increase water absorption
factors of NPP distribution
tropics distance from ocean altitude different climate
costal water are the most productive
more light waves tides currents and land proximity
autochthonous npp
carbon produced from within ecosystem
photosynthesis
allochthonous npp
carbon produced from outside ecosystem
assimilation efficiency AE
carnivores>herbivores
endotherms>ectotherms
net production efficiency
invertebrates>vertebrates
ectotherms>endotherms
large>small
carnivores>herbivores
non-social>social
gross production efficiency is
overall efficiency of converting ingested energy into secondary production
endotherms have
high ae but low npe
equations
AE=A/I NPE=P/A
GPE=AE*NPE=A/I*P/A=P/I
CE=I/Pn-1
TE=CE*GPE=Pn/Pn-1
tropic efficiency TE is
overall measure for quantifying energy transfer between levels
10% rule is
10% of energy consumed as biomass at five level is converted to biomass at next level
biomass pyramids
decreasing energy transfer through tropic levels corresponds with decrease in standing biomass
inverted pyramid in plankton dominated marine systems because of high turnover rates
nutrient cycling is
the transformation of organic nutrients into mineral form, making them available to plants again
retranslocation or reabsorption is
in autumn, chlorophyll production begins to decline
plant roots can reabsorb minerals form leaves than lost
yellow and organic pigments begin to show and anthocyanins are produced
decomposition is
the breakdown of chemical bonds of organic molecules, is the key process in recycling of nutrients within the ecosystem
decomposers are
organisms that feed on dead organic matter or detritus
size and function of decomposers
microfauna: bacteria and fungi
invertebrate detritivores: microfauna mesofauna macrofauna megafauna
bacteria are
the dominant decomposers of dead animal matter
aerobic and anaerobic
fungi are
the major decomposers of plant matter
litter bags are
used to examine the decomposition of plant litter
original mass remaining e^-kt
k=decomposition coefficient t=time unit used
factors effect decomposition
intrinsic(biotic): litter quality
extrinsic(abiotic): soil texture, soil ph climate
experiment show that
proteins and solubles decomposed the most quickly within first few days
cellulose and hemicellulose decomposed more slowly in three weeks
total carbon decomposed fast but speed down in three weeks and decline very slow
lignin majority remained intact
index litter quality shows that
inverse relationship between decomposition rate and its lignin content
mineralization is
the transformation of nutrients contained in organic compounds into inorganic compounds
immobilization is
the uptake and assimilation of minerals by microbial decomposers
net mineralization rate is
the difference between miner rate and immob rate
changes in nitrogen content
decline as leaching
increase as immob>miner
decline as miner>immob
as nitrogen decrease net miner rate increase
C:N ration is
measure of litter quality
microbes have lower C:N ration than plants
humus are
as decompositions processes, the litter degrades into a dark brown homogeneous organic matter
soil organic matter
as humus becomes embedded in the soil matrix
rhizosphere is
the region of the soil where plant roots function, an active zone of root growth and death with intense microbial and fungal activity
biogeochemical cycle is
the cycle flow of nutrients form the non living to the living and back to the non living components of the ecosystem
two cycle for maintaining life on earth
N and C cycle
two type of biogeochemical cycles are
gaseous and sedimentary
main pool of nutrients in gaseous cycle are
atmosphere and oceans
main nutrients in sedimentary are
soil rocks minerals
biogeochemical could not exist without
water cycle
hybrid of gaseous and sedimentary occur
as sulfur
biogeochemical have
input internal cycling output
wet fall are
nutrients by precipitation
dry fall are
nutrients by airborne particles and aerosols
net ecosystem productivity NEP
is carbon uptake by photosynthesis minus carbon loss(autotroph+heterotroph respiration
earth contain
100 million carbon 10^23
carbon pool is
involved in the global carbon cycle amounts to 55000 gigatonnes
arctic amplification is
decrease in sea ice has been correlated to increase in co2 emission
as temperature rises and ice melts, less radiations from the sun is reflected causing further heating and melting
net primary productivity is affected by
nitrogen
inputs are
exchanges from the surrounding environment into the ecosystem
outputs are
exchanges from inside the ecosystem to the surrounding environment
closed ecosystem is
one with minimal exchange with the surrounding environment
open ecosystem is
one that undergoes significant exchange from the surrounding environment
system ecology is introduced by
paul wies
a system is
a set of interrelated parts that work together to perform a function or functions within an environment
feedback refers
to the output of one system process affecting the process of another
positive feedback is
the continued amplification of a process
negative feedback is
damping or reversal of a process
dynamic equilibrium
regulate ecosystem states as a regulatory process
resistance stability is
the tendency for the system to remain the same when subject to a disturbance
resist changes
resilience stability is
the tendency to re establish a former state after a change is occurred
return to its original state
genetic diversity
the number of genotypes in a community
species diversity
the number of species in a community
functional diversity
the number of ecosystem functions played by species in a community
phylogenetic diversity
the amount of evolutionary history represented by species in a community
functional redundancy
ecosystem function increases with diversity reaches a plateau as niches are filled
singularity
each species has a unique role the decline once non native species are introduced
keystone
ecosystem function drops off sharply when diversity falls as a result of the loss of keystone species
alternate stable states
non transitory states that arise when ecosystems are disturbed past a critical threshold and follow a path that does not restore them
tipping points are
stress thresholds that once suppressed send a system on a different path
biodiversity ecosystem functioning hypothesis states that
ecosystems with more species are likely to not only increase stability but also maximize ecosystem function such as productivity
niche complementary
ecosystems will optimize resource use the more species are present with differing and complementary of niches
microcosm is
a small self contained system
mesocosm is
a larger self contained system
macrocosm is
include large scales such as lakes and forests
risk factors link with extinction
species with limited distribution
small populations
species with migrate seasonally
endemics have narrow ecological niches
require large home range
have direct interaction with human
international union for conservation of nature IUCN developed a classification for threatened species
critically endangered species
endangered species
vulnerable species
critically endangered species are
50 percent or greater probability of extinction within 10 years or 3 generations
endangered species are
20 percent of extinction within 20 years or five generations
vulnerable species are
10 percent or more of extinction within 100 years
at least one to assign in IUCN
observation decline in numbers of individuals
geographic area occupied by a species and the number of populations
the geographic area of individuals alive and the number of breeding individuals
expected decline in numbers of individuals habitat destruction continue
probability of species going extinct in certain years or generations
in canada we use
cosmic committee on the status o endangered wildlife in canada
traits increase likelihood of going extinct
large size
mature late
low reproductive output
large home range
biodiversity hotspots are
regions with unusual high species richness, endemism and level of threats
the primary cause of species extinction is
habitat destruction
the most effective way to preserve diversity is
protect habitats and whole community
small areas have
a greater edge to area ration that poses constrains for interior species
species are locally rare need
large area to be present in large enough numbers to sustain viable populations