UPD Bio 12 4th Exam Notes

Fourth Exam- Bio 12

Ecology: interaction between organisms and envi

-       Determines abundance and limits distribution

Components

1. ABIOTIC FACTORS: nonliving and physical factors
2. BIOTIC FACTORS: living; all the organisms in the individual’s environment

-       ecological time determines evolutionary time leading to evolutionary change

MAIN AREAS

1. Organismal Ecology: morpho, physio and behavioral adaptations of individual organisms in order to meet the challenges posed by their abiotic and biotic envi.

-       abiotic usually determines g.distribution

2. Population Ecology: how many individuals of a particular species live in a particular area
3. Community Ecology: focus on interaction of the community which affect its’ structure and organization

** ecosystem: all abiotic factors plus the entire community of species that exist in a certain area ( more than one)

4. Ecosystem Ecology: energy flow and cycling of chemicals among the various biotic and abiotic components
5. Landscape Ecology: how arrays of ecosystems are arranged in a geographic distribution

** landscape: consist of several ecosystems linked by change in material, energy and organisms.

** biosphere: global ecosystem

** use the precautionary principle

FACTORS AFFECTING THE DISTRIBUTION OF ORGANISMS

Biogeography: the study of the past and present distribution of individual species

1. dispersal: barriers to moving out

** specie transplant: potential and control range

** tens rule: one of ten introduced species manage to be a success and one out of ten to be common pests

2. behavior

-       insect oviposition biased on corn plants

-       key point is the evolution does not produce perfect organisms for every suitable habitat

-       environmental change may cause present adaptive behaviors to be maladaptive.

3. biotic factors

-       limitation on the successful reproduction of species when transplanted ( lack of negative or positive interaction )

4. abiotic factors

1. temp
2. water- osmolatrity of cells
3. sunlight

-       animals depending on photoperiod cues

4. wind

-       wind+ temp= windchill factor ( heatloss increased due to evap and convection

-       induces morphological limitation on plants

5. rocks and soil

 BEHAVIORAL ECOLOGY

Behavior: what a animal does and how it does it

-       has proximal and ultimate causes which always is related to Darwinian fitness

-       innate behavior: developmentally fixed regardless of environmental factors

Demography: study of the vital statistics that affect population size

1. life table: age-specific summary of survival pattern of a population
2. survivorship curve: graphic way to display the life table

-       a plot of the proportion or numbers in a cohort still alive at each age.

-       TYPE 1: low death rate-drops eventually

-       TYPE 2: continuous death rate

-       TYPE 3: sharp death rate curve but eventually levels out ( invertebrates)

K and R strategists

R: unstable envi, cheap and lots of offsprings

K: stable envi, few viable offsprings

 POPULATION ECOLOGY

Population: group Of 1 specie occupying a general area

2 characteristics

a. density: # of individuals per unit or area or volume

-  mark-recapture method: for fish and wildlife populations

b. dispersion: pattern of spacing among individuals within the geographic distribution of the population

- dispersion patterns

a. clumped in patches: most common

b. uniform- due to interaction of individuals

c. random spacing- lack of repulsion and interactions

Population growth

Change= birth-death in a time interval

êN/êT= bN-dN

r=b-d: to measure if a population is growing depending on value if its negative or positive

r=0 means ZPG, equilibrium

êN/êT=Rn

-       IDEAL CONDITIONS: exponential population growth which is characterized by intrinsic growth of increase, rmax

-       J –shaped curve

-       Usually if populations are new or unfilled envi, rebounding from catastrophe

CARRYING CAPACITY: maximum population size that a particular environment at a particular time with no degradation of the habitat ( K)

-       fluctuates with limited resources

-       energy limitation is the most significant determinant

LOGISTIC POPULATION GROWTH- incorporates the effect of population density on

POPULATION LIMITING FACTORS

-       look at the changes in b,d,e,I as population density rises

1. density dependent: birth rate that falls with increasing density or death rate that increases with increasing density

-       negative feedback

• intraspecific competition
• territoriality
• predation as prey # increases
• accumulation of waste product

2. d-independent:

-       why are certain habitats favorable to living and not?

** cyclic rise and fall of populations

linx and hare

human population

demographic transition

-       to keep zpg in 2 methods

-       age structure

-      importance

COMMUNITY ECOLOGY

Species richness: the number of species contained

Relative abundance: commonness and rarity of species

Individualistic vs. interactive hypothesis

-       abiotic vs. biotic dependency

INTERSPECIFIC INTERACTIONS AND COMMUNITY STRUCTURE

1. COMPETITION

-       Competitive exclusion principle, two similar species cannot coexist in the same place when they compete for the same limiting limited resources.

ECOLOGICAL NICHE: sum total of a species’ use of the biotic and abiotic resources in its environment

-       ecological role of organism

-       address plus occupation

RESOURCE DIFFERENTIATION: enables similar species to co-exist by shifting to other resources by one specie

2. PREDATION

-       extended to herbivory and parasitism

-       fleeing ( energy expenditure), active self-defense and alarm calls

-       camouflage or cryptic coloration

-       aposematic coloration: animals with effective chemical defenses are often brightly colored, a warning to predators

-       batesian mimicry: a palatable or harmless specie mimics an unpalatable or harmful model

-       mullerian mimicry: two or more unpalatable species mimic each other.

3. PARASITISM

-       host

-       endo, ecto ( mosquito/aphids), parasitoidism ( small wasps) laying eggs inside the host, eventually killing the host.

-       Pathogens

4. MUTUALISM

-       interspecific interaction that is beneficial to both

-       insect on narra tree, legume and nitrogen fixing bacteria

5. COMMENSALISM

TROPHIC STRUCTURE ( feeding relationships)

-       food chain: energy transfer between pp,pc, s and tc to d.

-       length is usually divided into 4 or 5 links called trophic levels

food chain length dependent on

1. energetic: inefficiency in energy transfer
2. dynamic stability: the longer the food chain, the less stable

-       recovery rate and setbacks from environmental shocks makes it difficult for top predators to recover

DOMINANT SPECIES: species with the heighest abundance pr highest biomass ( the sum weight of all the individuals in a population)

KEYSTONE SPECIE: dominance by ecological niche but not in numbers

-       bottom up model/top down model

ecological succession

-       lifeless place with no soil formation, autotrophic bacteria present at first ( primary succession)

-       secondary- devastated place but with soil intact, herbaceous species first, compared to primary that have mosses and lichens

biodiversity/species diversity

-       depends on size and geographic location

2 components of biodiversity

- specie richness: total number of different species in the community

- relative abundance: