AP ExamPart One Principles for Understanding

Our Environment

Orderly change of species in an ecosystem over time

Primary succession occurs when an area is newly exposed and has previously not had a biological community. The area lacks soil.◦ Cooled volcanic lava or a boulder rock slide

Secondary succession is more rapid b/c soil is already there.◦ Burned field

Climax community

Succession

Carbon cycle◦ Carbon sink-absorbs carbon (ocean, atm,etc)

Nitrogen cycle◦ nitrogen fixation, nitrification, assimilation,

ammonification, denitrification Phosphorus Cycle Sulfur Cycle Water Cycle

Cycles

Nitrogen fixationThe process of converting inorganic, molecular nitrogen in the atmosphere (N2)to ammonia. In nature it is carried out by a few species of bacteria, on which all life depends.

NitrificationThe process of oxidizing ammonia to nitrites (NO2

-) which are harmful to plants and then into nitrates (NO3

-) which are beneficial.

DenitrificationThe process of releasing fixed nitrogen back to molecular nitrogen (N2).

AssimilationThe process by which plants take in nitrates through their root hairs.

AmmonificationThe process of breaking down nitrogenous wastes and organic matter found in animal waste and dead plants and animals and converting into ammonia (NH3) for absorption by plants as ammonium ions. Therefore, decomposition rates affect the level of nutrients available to plants.

Human interventions◦ Ground and surface water depletion◦ Ground and surface water pollution◦ The clearing of vegetation, particularly in

temperate and tropical rainforests, interferes with the cycle by decreasing transpiration

Hydrologic cycle is powered by the sun and gravity

Water Cycle

Since the industrial revolution, we have dramatically increased the CO2 in our atm due to:◦ Deforestation, which decreases the plants available

for photosynthesis, thus decreasing CO2 uptake◦ Forest burning and returning the carbon in the

biomass of the forest to the atm by releasing it from the sink

◦ Increased combustion of fossil fuels, releasing carbon from the sink

Carbon Cycle

Some bacteria are capable of breaking the triple bond of nitrogen gas

Human Intervention◦ NO is released when fossil fuels are combusted.◦ NO forms nitric acid in atm making acid deposition◦ N2O gas is a greenhouse gas, from livestock waste

and commercial fertilizer◦ Nitrogen starts eutrophication when added to

water

Nitrogen

Very slow b/c there is no atm stage. Nearly all is in rocks or living organisms, b/c

ions do not dissolve well in water Human Intervention

◦ Phophate mines that form large pits can result in runoff pollution

◦ Removing vegetation lowers phosphorus availability

◦ Phosphorus addition can lead to eutrophication

Phosphorus

Most sulfur found as iron disufide (pyrite) or as mineral salt: calcium sulfate (gypsum)

Released by weathering and volcanic activity

Human Intervention◦ Fossil fuel combustion, especially coal◦ Refining of petroleum and smelting◦ Coal mining damages aquatic ecosystems◦ Large amounts of sulfur dioxide and sulfate

aerosols cool the atmosphere b/c they prevent UV radiation

Sulfur

Law of tolerance: bell curve Symbiosis

◦ Mutualism: lichen (fungus and algae/cyanobacteria)◦ Parasitism: ticks, fleas◦ Commensalism: barnacles on a whale

Keystone species: abundance does not reflect importance- ie. Top predators

Vocab/concepts

Anthropogenic◦ From man

Biocentric Environmental Justice Intrinsic value Negative feedback loops

◦ Considered good Positive feedback loops

◦ Considered bad

Vocab

Pyramid of biomass- the mass of living matter at each level

Pyramid of energy- how much energy is passed on at each trophic level◦ Reasons for lost energy

Can’t digest May use more energy to catch food Consumer may not eat entire killed organism Loss to thermal energy Average transfer is 10% range is about 80-95%

Pyramid of numbers -how many individuals at each trophic level◦ Can be inverted if a few trees supporting lots of

insects and birds

Pyramids

Diffuse energy is considered low quality (ocean)

Concentrated energy is high quality (coal) Potential energy is stored energy in food,

etc A calorie is the amount of energy needed to

increase the temperature of 1 g of water 1°C

One calorie = 4.184 J (joules)

Energy

The study of energy conversion The first law- Law of Conservation of Energy

◦ Energy can neither be created not destroyed; it can only change from one form to another

The second law of Thermodynamics◦ With each energy conversion in a closed system,

the energy change proceeds toward entropy◦ Disorganization is favored in nature

Stack of soda can example

Thermodynamics

Individual Species: group that reproduce fertile

offspring Population: a single species in an area Community: group of interacting

populations Ecosystem includes biotic and abiotic

factors Biosphere

Ecosystem Hierarchy

Coevolution: selective pressures on each other Selective pressures include:

◦ Physiological stress, predation, competition and chance

Divergent Evolution◦ Adaptive radiation- Galapagos finches

Convergent Evolution◦ Lacks recent ancestor but develop similar features

ie. Wings on a bird and wings on an insect Competitive exclusion: two organisms cannot

occupy the same niche for an indefinite period with out one eventually migrating, dying or undergoing resource partitioning.

Evolution

Tropics between 23°N and 23°S Temperate between tropics and Polar Polar region starts at 66°N or 66°S Two most important aspects of climate are

precipitation and temperature Temperature cools as you move away from

the equator Altitude affects the biome-vertical zonation

Biomes

Stationary, so adapted for weather Succulents store water in stem Stems might need to photosynthesize

(spines) Broadleaf evergreens keep their leaves all

year (live oak) Broadleaf deciduous-expend lots of energy to

grow back leaves in the spring Conifers-most evergreens, needles decrease

water loss Allelopathy- plants secrete toxins into soil

Plants

Freshwater Biomes◦ Rivers, streams, lakes, ponds and all inland

wetlands including swamps, bogs, marshes and fens

Marine Biomes◦ Coral reefs, coastal marshes and swamps,

estuaries, barrier islands and the open ocean

Aquatic Biomes

Plankton: float or swim weakly◦ Phytoplankton: cyanobacteria and algae◦ Zooplankton: herbivores and carnivores

Nekton: swim and are consumers◦ Sharks, tuna, bass and perch

Benthic: live on the bottom◦ Often decomposers or detritovores

Aquatic Organisms

Nutrients Dissolved oxygen Temperature depth Turbidity

Aquatic Limiting Factors

Equivalent to tropical rainforest Shallow, clear, warm water Mutualistic relationship between a

carnivorous cnidarians and an autotrophic alga

The coral polyps protect the algae within its tissues, algae provide food

Coral secrete shell of calcium carbonate Reefs sensitive to pH change and increases in

turbidity

Coral Reefs

Tropical trees that grow along coastlines They function to catch sediment, remove

nutrients, and serve to protect coastlines by preventing erosion

Large biodiversity Serve as nurseries and nesting areas Fallen leaves provide food for detritovores Humans threaten mangroves by:

◦ Use wood for lumber and charcoal◦ Aquacluture - raise saltwater species◦ Urbaninzation and coastline development

Mangrove Swamps

Where freshwater empties into salt water Varying levels of salinity=brackish water Tremendous biodiversity Nutrient rich, turbid, large amounts of sediment Flowing water may contain numerous

pollutants-oil, nitrogen, phosphorus + fecal High NPP and serves as a nursery for shrimp,

oysters, clams and numerous nekton species Humans interventions include

◦ -recreation, fishing and aquaculture and development

Estuaries

Exponential Growth- J shaped curve◦ Growth without restrictions◦ r(N)=ΔN/ Δt [r=growth rate, N= number, t= time]◦ Same as biotic potential

Logistic Growth- S shaped curve◦ Carrying capacity(K): max pop that can be

sustained indefinitely. It is not fixed. Changes by season.

◦ ΔN/ Δt=rN(1-N/K) Rule of 70

◦ Doubling time = 70/r

Population Biology

Resistance increases with population Density dependent factors

◦ Disease, competition, predation and parasitism, territoriality, increased stress and aggression, decreased immunity and fertility

Density Independent factors◦ Floods, fires, hurricanes, human-induced

disruption Dispersion

◦ Clumped, uniform, random

Environmental Resistance

Selected strategists

R-selected K-selected

Short life Rapid growth Early maturity Many small offspring Little parental care Little investment in individual

offspring Adapted to unstable environment Pioneers, colonizers Niche generalists Prey Regulated mainly by extrinsic

factors Low trophic level

Long life Slower growth Later maturity Fewer large offspring High parental care High investment in individual

offspring Adapted to stable environment Later stages of succession Niche specialists Predators Regulated mainly by extrinsic

factors High-trophic level

Natality-production of new individuals by birth, hatching, germination or cloning

Fecundity-physical ability to reproduce Fertility-is a measure of the number of offspring produced

by a female Mortality- number that die in a particular time frame

divided by the number living at the beginning of the time frame

Survivorship-proportion in a population that survive to a particular age.

Life expectancy-probable number of years of survival for an individual of a certain age

Life span- longest period of life reached by a given organism

Survivorship

Late-loss curve: more deaths in older organisms◦ Top consumers and K strategists

Constant-loss curve: death equal in all ages◦ Sea gulls, rodents, and some plants

Early-loss curve: probability of survival increases as these organisms age◦ Turtles and redwood trees

Type IV curve: early life mortality, which levels then rises again later◦ Deer and crabs

Survivorship curves