Ecology Exam 2

Covers Ecosystem Ecology

Clouds near the equator move which direction?

East to west

Clouds in the higher latitudes move which direction?

West to east

What is the main determiner of how much solar radiation the ground receives

The angle of ground relative to the angle of incoming rays (Cosine Law)

What is the cosine law

S=cos(a)

What is the equinox

When the equator gets the most direct sun so both the northern and southern hemispheres get equal light

what two things related to the sun are highly affected by latitude?

Day length and seasonality

What is the Coriolis effect

the movement of the Earth rotating while the air rotates around

Inter-tropical convergance

the area on the ground where the two Hadley cells come together

Trade winds

Wind patterns within the Hadley cells that are very reliable

Ferrel cell

30 to 60 N and S

When the north pole is tilted towards the sun what season is it in the southern hemisphere?

Winter

Near the equator it is:

Very hot and not very seasonable

In the mid latitudes it is:

seasonal in temperature and daylength, especially away from oceans

Near the poles it is:

extremely cold and seasonal

Rising air at the convergence cools and sheds ____ as it rises

rain

\n The descending air \n to the N & S of the Hadley cells heats as it descends, this means \n ____

Dry

Tropical rain forest dominates near the ______

tropical convergence

Desert dominates in the latitudes of the _______

descending limbs of the Hadley cells

Biomes of mid-latitudes include:

Deciduous forests, prairies, chaparral, southern \n taiga

Biomes of high latitudes include:

Taiga (boreal forest) and Tundra

What is the adiabatic lapse rate

1°C for every 100 meters of increased elevation

What are the ways to make rain?

Mountains, frontal systems, local convection, and tropical convergance

what is a side effect of the mountain way to make rain?

Rain shadows which usually create deserts

Frontal systems are an example of what feedback loop?

A positive feedback loop

How is rain made?

Rain is made by moving moist air upwards until it cools to the dewpoint, and water vapor begins to condense

What vegetation are tropical rainforests dominated by?

Broad leaf evergreens

What is the term for plants growing on plants?

Epiphites

What is the dominant vegetation of tropical seasonal forests?

dry deciduous broad leafs

There ___ clear lines between biomes

are no

What is the dominant vegetation of tropical savanna and grasslands?

mixture of trees and grasses, grasslands have mostly grass while savannas have occasional drought resistent trees

Why is grass so important to grasslands and savannas?

Grass supports a high biomass of large area grazers since 2/3rds of it is below ground and it is edible.

The Serengeti savanna is threatened by wildfire ____

Suppression

A desert is defined when:

potential evapotranspiration far exceeds rainfall for most of the year

What are the ways that there are deserts?

In the spot between the hadley and ferrel cells, and rain shadows

Why is the broadleaf sclerophyll/chaparral considered its own biome?

It has unique vegetation dominated by drought resistent shrubs and has a high population of people living in it

emperate grassland/prairie is largely maintained by what?

Fires

What vegetation dominated temperate decidious forests?

winter-decidious trees

What are spring ephemerals characterized by

Completing most of their growth in a brief period of spring and remaining dormant as seeds for the rest of the year

Temperate rainforests are characterized as:

Wet maritime climate with the tallest trees

Boreal forests or tiaga are often called the moose, spruce biome, why?

Moose and spruce are abundant throughout the biome yet are not directly part of each others food chains, moose prefer broadleaf trees and shrubs that come from disturbed lands

Why do trees in the boreal forest or tiaga have a monopodial shape rather than an umbrella?

Monopodial is more vertical which catches more of the suns rays that are towards the horizon versus above them

permafrost:

a layer of soil a short distance below the surface that is frozen all the time

Why does surface matter in terms of water on earth?

because most ecosystems run on solar energy arriving at the earth’s surface

Freshwater is important to us but very _____

scarce

water has a very high specific heat, what does this mean?

it takes a lot of E loss or gain to change water temperature

What do you need to be an endotherm in water?

Be big with a lower surface area to volume ratio or come out of the water periodically

Diffusion is ____ in water vs air

slower

Gas exchange in water is much quicker when the water is _____

moving

Why are Sessile algae and animals are often most abundant in the moving water of rivers and shorelines

Because the moving water speeds up the uptake of CO2 and nutrients

What are the main limitations in water?

nutrients and light

Marine ecosystems are more productive _____

near land because more nutrient rich currents come to the surface and light is more available

There is ____ more saltwater than freshwater

MUCH

A continental shelf:

has basically the same bedrock as continental rock, and is confined to the immediate edges of the continents

The deep sea floor:

has dark bedrock made of the basaltic geologically distinct ocean floor and does not have many nutrients

Palagic means

open water

Benthic means

On or near bottom (earth)

Surface palagic is

near the surface and primary production (photosynthesis) will be limited by nutrients

Deep palagic is

limited by light, since there is no local primary productivity

Shallow Benthic are genrally

rich and productive

Deep Benthic is also called the

abyssal plane

Deep benthic is limited by

light and nutrient “rain”

What is unique about mid-ocean ridges?

There is no sunlight but they host an entire productive ecosystem based on sulfur bacteria living off the mineral-laden hot water coming up from vents in the ocean floor

Mid-ocean ridges often have _______ concentrations of life

Extremely dense

The energy running the biosphere is ultimately

Solar energy captured by photosynthesis

How do bacteria support life in mid-ocean ridges

capturing chemical energy by oxidizing the sulfides (H2S, \n FeS, etc.) through chemiosis

The energy running the mid-ocean ridge community ______ captured by photosynthesis

is not

Bacteria in mid-ocean vents make their living by ______ which means they need what provided from what process?

Oxidizing, oxygen, provided by photosynthesis

As energy flows through the Earth it is _______

degraded (made less concentrated)

What type of system is the Earth in terms of energy?

an open system

The energy leaving the earth is less concentrated, and therefore what?

Less able to do work

A single photon of visible light has roughly how much of the energy of a single photon of infrared?

10x

The Earth is what type of system in regards to matter? This means what?

A closed system which means matter doesn’t enter or leave in significant amounts

Has Earth always been a closed system in terms of matter?

No, 4.6 billion years ago during the hadean period asteriod strikes were common

matter and energy movements are what?

Couples (or paired)

An efficiancy:

is a basic concept that gets used a lot in ecosystem ecology and other areas of science that is a dimensionless number that can be expressed as a proportion

Of the solar energy that hits a leaf how much of it is captured by phtosynthesis?

5%

Efficiency of photosynthesis =

E captured by photosynthesis / E hitting the leaf = \~ 0.05

primary productivity is:

Solar energy captured by photosynthesis in plants

What are the units of primary production

biomass (dry g/m^2/year) or energy (joules)

What is NPP

Net primary productivity (NPP) is GPP minus plant respiration (proportional to total accumulated plant matter \n produced)

What is the NPP of tropical rainforests

2000 g/m2/year

What is the NPP of temperate grasslands

1200 g/m2/year

What is the NPP of deserts

70 g/m2/year

What is the NPP of marshes and coral reefs

2000 to 2500 g/m2/year

What is the NPP of productive ocean and inland water

400 g/m2/year

What is the NPP of open ocean

125 g/m2/year

Terrestrial NPP is highest when:

its warm (faster biochemistry), there’s a long growing season, its wet (CO2 uptake not limited), and less importantly there’s good soil

Nutrient availability \* Light availability (+ Warm enough) ->

Productivity

Where do nutrients come from?

Recycling from decay, weathering of rocks and soil when exposed to air or water (fastest on land)

What is a limiting resource?

The resource present in the lowest concentration \n relative to need is the limiting resource

Ocean primary productivity is high where?

Where nutrients are high such as close to the coast, in upwelling zones, and when dust storms bring desert dust to the mid-ocean

What is the problem that faces cattail marshes?

Nutrients can be locked up in organic matter which may decay slowly when oxygen in the sediments is low and roots need oxygen to survive and thrive

What are Aerenchyma?

an open, air-filled tissue in leaves, rhizomes \n (underground stems) and roots that moves oxygen into the roots and surrounding sediments. This allows the roots to breathe, and the sediments to decay more quickly so it is a solution to marsh plants

Why is the high productivity of coral reefs odd?

since their waters do not generally have high nutrient concentrations, they have lower plankton since coral are filter feeders

coral animal + zooxanthellae (algae) \n symbiosis implies what?

very tight nutrient cycling

What is a basic schematic of the Nitrogen cycle?

Plants uptake Nitrogen, animals and other organisms eat the plants (and N), then they die and decay or mineralize

Why is N2 not available for biological use for most organisms

It is triple bonded which makes it really stable and the bonds require a lot of energy to break

What is fixation

Transforming one substance or element (N) into one more chemically active (Ammonia or NOx)

Nitrogen moves from one chemical form to another, but it also moves from one ______ to another

Physical “pool”, meaning it changes what container it is in such as dissolved in water or in the air

What is resident time?

How long an element stays in a given pool