IB 203 Exam 3

landscape ecology

Spatial patterns and their relationship to ecological processes

What are the greenhouses gases?

CH4, CFC, NO2

What is the 2nd law of thermodynamics?

Any transfer of energy is dispersed and unusable
Energy decreases within each trophic level

Nitrogen fixation

Converting N2 into a biologically useful form

Source

Pool where net input is lower than output

Sink

Pool where net input is greater than output

What is climate change trajectory?

As extreme weather events increase in frequency, then the magnitude of severe ecological disturbances increase.

What does a reduction in aerosols do?

They increase the temperature because aerosols reflect sunlight.

What has caused rapid recent death of coral reefs globally?

Increased CO2 absorbed in oceans, lowering pH and increased stress.

What is NPP?

NPP is the energy captured by plants through photosynthesis. High NPP correlates to more sunlight needed for the heterotroph. High NPP is found in wet and humid environments.

Two ultimate sources of nutrients in ecosystems?

Minerals in rocks and gases in atmosphere

Components in soil

minerals, organic matter, water, organisms

Greenhouse effect

Short wave radiation from the sun passes through earths atmosphere. It is absorbed by the earth and re-emitted as long wave radiation. This is absorbed by greenhouses gases which causes global warming.

Why are temperatures at the equator warmer than the poles?

Temperature is warmer at the equator because sun rays are more direct and indirect at the poles. The more solar radiation, the warmer the equator is.

weather

Current conditions (temperature, precipitation, humidity)

Climate

Long term average/variability in weather patterns measured over decades.

What is solar radiation?

The sun is the ultimate source of energy that drives the global climate system

What is a factor that drives global temperature?

Latitudinal differences in solar radiation

What is global temperature influenced by?

Solar radiation, green houses gases, topography, ocean currents

What is global precipitation influenced by?

Atmospheric circulation cells, ocean currents, and topography

The rain shadow effect

The windward slope facing the prevailing winds has high precipitation and lush vegetation; the leeward slope gets little precipitation

Eccentricity

Earths orbit shape and location around the sun

Axial tilt

The greater the earths tilt, the warmer summers and colder winters.

Precession

Earths seasons affected by earths orbit and wobble.

Milankovitch cycles

Long term time scale changes in the shape earth's orbit and tilt that cause glacial periods and interglacial periods.
Eccentricity
Axial Tilt
Precession

Anthropogenic Climate Change

Short term time scales changes driven by human activities that cause global warming.

Warm air molecules rise as they expand and become ....

less dense

Cold air molecules fall as they contract when cooled and become ...

more dense

Aerosols

Liquid droplets that remain suspended in the atmosphere for a long time increasing reflectivity and cooling

How do humans emit CO2?

Deforestation/land usage during fall and winter and burning fossil fuels releasing greenhouses gases

How do we reduce global warming levels?

Switch to renewable energy and use energy efficient appliances.
- solar electricity
- wind generated electricity
-biofuels

Carbon Footprint

Total amount of greenhouses gases (CO2) emitted by an individual

What is the significance of keeping the global climate under 1.5 to 2 degrees of warming?

Going over 2 degrees will have severe effects on ecosystems. Extreme weather, species extinction, and health related risks.

Positive feedback mechanisms

1. When ice melts, it exposes darker oceans and rising sea levels.
2. As permafrost thaws, greenhouses gases are emitted.
3. As forests start dying, this leads to reduced carbon absorption.

Kneeling curve Trend (hockey stick graph)

Upward trend is due to human activities burning fossil fuels and deforestation. This increases CO2 levels which are released in large amounts into the atmosphere.

Photosynthesis

Chemical energy generated by Autotrophs
6CO2 + 6H2O + energy -> C6H12O6 + 6O2
Occurs during the day
Limited by light/nutrients

Gross primary production (GPP)

Total amount of carbon fixed by autotrophs

Respiration

Process of converting energy stored in form of carbs into usable chemical energy
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
Occurs during the day and night
Limited by temp/photosynthesis

How is NPP measured?

Harvest plant biomass
Dendrometer bands (measurement of tree diameters)
Remote sensing over large areas & time to understand deforestation

Heterotrophs

Organisms that depend on other organisms for their food.

Autotrophs

Organisms that make their own food

Net ecosystem exchange (NEE)

Total amount of energy fixed by autotrophs in an increasing in living plant matter

Inuit people

Hunter gathers relying heavily on subsistence hunting & fishing

Detritus

Dead organic matter and the decomposing organisms living among it

Marine Biomass pyramid

It appears inverted due to algal turnover and life span increases as you move up each trophic level

Factors that determine energy flow between trophic levels?

1. Amount of NPP
2. Proportion of each trophic level consumed
3. Nutritional content of autotrophs
4. Efficiency of energy transfers

Three components of trophic efficiency:

1. consumption efficiency
2. assimilation efficiency
3. production efficiency

Bioaccumulation

Chemicals become more concentrated in tissues overtime

Biomagnificiation

Higher trophic level animals carry a larger amount of toxins

Mechanical Weathering

Physical breakdown of rocks
- coastal tundras
- desert

Chemical weathering

Chemical reactions release soluble forms of the mineral elements
- statues corroding over the years

Nitrogen resorption

N recycled through resorption
Breakdown of chlorophyll and re/uptake of N
Greater the change in leaf colors, the greater the N resorption

How do plants and microorganisms take up nutrients?

In simple, soluble forms

How do animals get their nutrients

Complex molecules

Plants have a higher C:N ratio than animals

True

Decomposition

Detritivores breaking down detritus to obtain energy and nutrients

Fragmentation

Increases surface area, which facilitates chemical breakdown

Mineralization

Chemical conversion of organic matter into inorganic nutrients

What tools do landscape ecologists use?

GIS
remote sensing analysis
process based modeling

Geographic information systems (GIS)

Computer based systems allowing storage, display and analysis of spatial data.
Used in:
- landscape planning
- urban development
- conservation

Landscape

A heterogenous mosaic of elements or ecosystems
Landscape mosaics:
- habitats
- plant communities
- topography

Landscape Composition

Types of elements & amount of each type

Landscape Structure

Physical configuration of the landscape
- size of patches
- whether patches are dispersed or aggregated

How does global warming affect corals?

Increased CO2 absorbed in oceans, lowering pH and increased stress

Nitrogenase

An enzyme that only occurs in bacteria that used during nitrogen fixation.

What does it mean if plants have a higher C:N ratio?

Herbivores must consumer more food than carnivores to obtain the nutrients.