APES Semester 1 Review

2

Positive and Negative Feedback

• Positive Feedback

• Often a BAD thing

• Something causes the mechanism to accelerate in one

direction

• Ex: Climate Change; Childbirth

• Negative Feedback

• Often a GOOD thing

• Something causes the mechanism to slow down and

return to original condition (keeps it at equilibrium)

• Ex: Body temperature regulation; Predator/Prey

relationships

3

Chemistry Basics

• Atoms – basic units of matter

• Atoms can gain and lose

electrons (-) – ions

• Gains electons – negative ion

• Loses electrons – positive ion

• Atoms can gain and lose

neutrons – isotopes

• Changes overall mass of atom

4

Water Chemistry

• Water is unique among most chemicals• Covalent molecule (shared electrons) with one

Oxygen and two hydrogens

• Water molecules can bond to OTHER water

molecules via Hydrogen bonds

• Oxygen is more electronegative so electrons

trend to Oxygen and away from Hydrogens

• Creates positive (H) and negative (O) ends of

molecule

• These charges can create bonds (Hydrogen

Bonds)

• These attractive forces between water

molecules leads to its properties (surface

tension, cohesion, adhesion, etc.)

Primary vs. Secondary Succession

During

succession

organisms

modify their

surroundings

which in turn

creates

suitable

conditions for

succeeding

organisms

Primary vs. Secondary Succession (cont.)

Secondary succession begins on the soil where there was living

organisms previously, but have vanished due to natural or

anthropogenic causes

Soil Horizons

O Horizon

A Horizon

E Horizon

B Horizon

C Horizon

Partly decayed organic material

Mineral matter with some humus

Partially altered parent material

Zone of accumulation (Nutrient/H2O)

Zone of leaching

=

=

=

=

=

Productivity in Ecosystems• Plants obtain sunlight and convert it into usable,

chemical energy

– This is Primary Production

– Gross Primary Production is ALL the chemical energy

produced

– Net Primary Production is the energy NOT used by the plant

after it uses what it needs for basic processes (growth,

reproduction, etc.)

• To determine the difference, take GPP and subtract Energy Used by

Plants to see how much energy is theoretically available to any consumer

(the NPP)

• Animals and other organisms can CONSUME plants,

taking in that usable chemical energy

– They then use these nutrients to grow, reproduce, and create

new biomass

– This is known as Secondary Production

An organism’s role in their environment and

the resources they exploit

Ecological Niche

Realized Niche –

the actual part of the niche an

organism occupies due to

competition

Fundamental Niche –

overall niche an organism can

live in

Competition

Intra-specific competition is competition between members of the same species for resources.

Inter-specific competition is when two different species compete for the same resources.

Competitive exclusion principle states

that the niches of organisms can only

overlap for a very brief time.

Phase Shift

• Change in dominant species

in an ecosystem

–Common example: Coral vs

Algae (such as in Kaneohe

Bay)• Nutrients go up and make the

ecosystem more suitable for algae– They bloom and cover the coral

• As either nutrient content or light availability

go down, algae die off and substrate is

available again for coral recruitment; the

coral animal flourishes

Thermal Stratification of Lakes

1. Epilimnion

2. Thermocline

3. Hypolimnion

Biomes

Both abiotic and biotic factors characterize large terrestrial

regions of the biosphere. These are classified as biomes.

Each one is characterized by distinct climate and specific life-

forms. climate – long term patterns of weather

Edge Effect or Ecotone

Land zone Transition zone Aquatic zone

Number

of species

Species in land zoneSpecies in aquatic zone

Species in transition zone only

Hunter-gatherers survived

collecting wild plants and

hunting native animals.

Generally nomadic. High

infant mortality rate short life

span (30-40 years).

Advanced groups used more

advanced tools, converted

forests to grasslands, and

contributed to the extinction

of some large animals.

Small

population

Small

ecological

footprint

Migration

Limited

technology

Agricultural Revolution

Shift from nomadic hunting and gathering

to a settled community.

• Farmers provided

more food than

needed by their

own family

• Towns and

villages formed

(Urbanization)

• Increased life

span

• Habitat

destruction/sla

sh-and-burn

• Soil erosion

and

overgrazing

• Pollution

Industrial RevolutionBegan in England and spread to the United States in the early 1800‘s. Shift from renewable resources such as wood and water to nonrenewable fossil fuels.

• Centralized factories to mass-produce goods

• Improved agricultural technology led to increase in urban population

• Air pollution• Dangerous

work conditions

Green Revolution (1950-1970)

Increased yields per unit of area of cropland

Involved three steps:

• developing and planting monocultures of

key crops

• lavishing fertilizer, pesticides and water on

crops to produce high yields

• increasing the intensity and frequency of

cropping