08_EnvLife

8/11/2019 08_EnvLife

http://slidepdf.com/reader/full/08envlife 1/97

Chapter 4

Environments

and Life

8/11/2019 08_EnvLife


What is your current classification?

A. Freshman

B. Sophomore

C. Junior

D. Senior

8/11/2019 08_EnvLife


Guiding Questions

• What factors determine the ecological

niches of species, and by what means do

species obtain nutrition?

• What factors govern the geographic

distribution of species?

• What factors govern the distribution ofaquatic life?

8/11/2019 08_EnvLife


Environmental Differences

• Tropical vs Polar - Terrestrial and Marine

• Low vs High Elevation

• Shallow vs Deep

• Wet vs Dry

8/11/2019 08_EnvLife


Hypsometric Curve

• Curve showing the proportions of the

Earth’s surface above and below sea level

8/11/2019 08_EnvLife


Hypsometric Curve

8/11/2019 08_EnvLife


QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this p icture.

8/11/2019 08_EnvLife


Climate

• Climate

– Controls distribution of species globally

– Has changed through time

• Plate tectonics and other changes affect

climate

8/11/2019 08_EnvLife


Ecology

• Ecology

– Study of the factors that govern the distribution andabundance of organisms in natural environments

• Habitats

– Environments on or close to Earth’s surface inhabited by life

• Terrestrial

• Aquatic – Marine

– Freshwater

8/11/2019 08_EnvLife


Ecology• Ecologic niche

– The way a species relates to its environment, including food,nutrients, physical and chemical conditions

• Life habit

– The way a species lives within its niche

• Limiting factors – Naturally occurring, restricting condition (physical and chemical)

– Competition

• Shared drive for limited resources

– Predation

8/11/2019 08_EnvLife


Competition

Arises because organisms share space

Predation also comes in here by possibly

limiting or preventing another species

from inhabiting a particular

environment.

8/11/2019 08_EnvLife


Ecosystem

• Ecosystem

– Organisms of a community and the physical

environment they occupy

• Population

– Group of individuals that belong to a single

species and live together in a particular area

8/11/2019 08_EnvLife


Ecosystem

• Ecologic community

– Populations of several species living in a habitat

• Producers – Photosynthesizing organisms; foundation of community

• Consumers

– Herbivores: feed on producers

– Carnivores: feed on other consumers

8/11/2019 08_EnvLife


Ecosystem

• Biota – Fauna: animals and protozoans of an ecosystem

– Flora: plants and plantlike protists

• Food chain

– Sequence of consumption for producers to consumers

8/11/2019 08_EnvLife


Food Web

• Food web

– More complex than simple food chain

• More common

– Several species occupy each level

8/11/2019 08_EnvLife


Ecosystem

• Parasites

– Feed on living

organisms

• Scavengers

– Feed on organisms that

are already dead

8/11/2019 08_EnvLife


Ecology

The movement of materials through an ecosystem.

Components within ovals are consumers.

8/11/2019 08_EnvLife


Figure 4-35

(p. 134)Interdependence

of photosynthesis

and respiration.

8/11/2019 08_EnvLife


Figure 4-38 (p. 136)

Simple pyramid of ocean life.

8/11/2019 08_EnvLife


Biogeography

The distribution and abundance of

organisms on a broad geographicscale.

8/11/2019 08_EnvLife


Biogeography

• Temperature

• Moisture

• Nutrients

8/11/2019 08_EnvLife


Ecosystem• Diversity

– The variety of species that live together within a

community

• Lower in more difficult habitats

• Predation influences diversity

– Heavy can reduce diversity

– Moderate can increase diversity by reducing competition

• Opportunistic species

– Species that specialize in invading newly vacated

habitats

8/11/2019 08_EnvLife


Biogeography

• Distribution and

abundance of

organisms on a broadgeographic scale

• Limiting factors

– Diversity increases

toward equator

– Barriers can affect

dispersal

8/11/2019 08_EnvLife


Life Habitats

The mode by which an organism lives, feeds

in an environment

1. Tropical vs. Polar

2. Low vs high altitude

3. Shallow vs deep4. Benthic vs. Planktonic

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


Atmosphere

• Regulates Earth’s

temperature (-18°C w/o

atmosphere)

• Composition

– N2, O2, CO2

• Tilt of the Earth affectssolar insulation,

temperature, and climate

8/11/2019 08_EnvLife


In our present atmosphere,

concentrations of O2 and CO2 are:

A. O2 > CO2

B. O2 < CO2

C. O2 = CO

2

8/11/2019 08_EnvLife


The Atmosphere

• Nitrogen -78%

• Oxygen - 21%

• Carbon dioxide (CO2 ) - 0.037% or 370 ppm

• Methane (CH4) - 0.00018% or 1800 ppb

8/11/2019 08_EnvLife


Solar Radiation

Daylight

Which receives more hours of daylight?

Equator vs Poles

The amount of daylight (# of hours) averagedover a year is the same at the poles as at the

equator

8/11/2019 08_EnvLife


SolarRadiation

8/11/2019 08_EnvLife


Solar Radiation

• Temperature difference is due to the angleof the sunlight and the albedo

• In the high latitudes, the sun hits at a lowangle and therefore the unit energy ofsunlight is spread over a large cross-sectional area of the earth’s surface. In the

tropics, the sun hits directly and therefore ismuch more concentrated

8/11/2019 08_EnvLife


Solar Radiation

8/11/2019 08_EnvLife


Solar Radiation

Qui ckTime™ and a TIFF (Uncompress ed) decomp ressor are needed to see this pic tu

Albedo refers to thereflectivity of the Earth’ssurface

1. Snow and ice is veryreflective - much of the solarradiation is reflected by tothe solar system

2. Water has a low albedo andabsorbs a lot of the solarradiation

8/11/2019 08_EnvLife


Solar Radiation

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

8/11/2019 08_EnvLife


Solar Radiation

8/11/2019 08_EnvLife


Solar Radiation

• When do we have summers?

• True or False

• Summers on Earth occur when it passes

closest to the Sun

8/11/2019 08_EnvLife


Solar Radiation

• Obliquity or Tilt (23.5°) of the to Earth’s

rotational axis

• This tilt gives us seasons. Summer is when

the northern or southern hemisphere is point

towards the Sun

8/11/2019 08_EnvLife


Atmosphere

• Regulates Earth’stemperature

• Composition

– N2, O2, CO2

• Tilt of the Earthaffects solarinsulation,

temperature, andclimate

8/11/2019 08_EnvLife


Solar Radiation

Heat Capacity

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


Movement of Air mass

• Rises at Eq. and sinks near Poles

• The high solar radiation at the equator heatsthe air masses, causing them to rise(buoyant).

• As the air rises, the temperature of the airmass decreases

8/11/2019 08_EnvLife


Atmospheric Circulation

• Net transport

– Air sinks at the poles,

rises at the equator

– Simplified model

• No tilt

• No Coriolis effect

8/11/2019 08_EnvLife


Rising Air QuickTime™ and a TIFF ( Uncompressed) decompressor are needed to see this picture.

As the air rises, the temperature of the air mass

decreases (adiabatic lapse rate 5°C/km)

Cold air holds less water vapor. Voila, rain and the tropical rainforest. Low pressure systems

usually have rain because the rising air drop water

as the air ascends and cools

8/11/2019 08_EnvLife


Rising Air


8/11/2019 08_EnvLife



• Coriolis effect

• Earth’s rotation causes

air and water massesto be defected to the

right (clockwise) in

the northern

hemisphere – Counterclockwise for

southern hemisphere

8/11/2019 08_EnvLife



• If we reverse the direction

and launch a rocket from

Panama towards

Washington DC, whichway will it curve?

• A = Right

• B = Left

• C = Not at all because

Panama is close to the Eq.

8/11/2019 08_EnvLife


Coriolis force

• Deflection of moving objects to the right in

the No. Hemisphere and left in the So.

Hemisphere

8/11/2019 08_EnvLife


Coriolis

Force

8/11/2019 08_EnvLife



• Actual pattern is more

complex

– Three circulation cells

– Trade winds, westerlies,

easterlies

• Intertropical convergence

zone

– Northern, southern trade

winds converge nearequator

• Changes seasonally

8/11/2019 08_EnvLife


Temperature Variations

• Atmosphere retainsheat

• Solar radiation

– Absorbed and turnedinto heat energy

– Reflected

• 6-10% ocean

• 5-30% forest• 45-95% ice and snow

8/11/2019 08_EnvLife


Trade winds

QuickTime™ and a TIFF (Uncompressed) decompress or are needed to see this picture.

• As the dry airdescending

around 30° begins to flow back towards

the Eq. it isdeflected tothe right.

T d i d

8/11/2019 08_EnvLife


Trade windsAs the dry air descending around 30° begins to flow back

towards the Eq. it is deflected to the right.


8/11/2019 08_EnvLife


Trade winds

The NE and SE trades converge on thelatitude where the maximum in

convection (rising air) is occurring. This

is the warmest location. Today, this is between 4 and 10°N and is termed the

Inter-Tropical Convergence Zone

(ITCZ)

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


The Terrestrial Realm

• Latitudinal Zones and Vegetation

• Rain forests

• Deserts

• Savannah Grasslands

• Temperate Forest

• Conifer or Evergreen Forest

• Tundra

8/11/2019 08_EnvLife


Terrestrial Realm

• Vegetation follows

climatic zone

– Tropical rain forest

– Desert savannahs

– Temperate forests

– Polar tundra

8/11/2019 08_EnvLife


Terrestrial Realm

• Tropical Climates

– 18 – 20° C (64 – 68° F)

– 0 – 30° latitude

• Tropical Rain Forest

– Dense vegetation

8/11/2019 08_EnvLife


Rain forests

• develop under the

tropical low pressure

systems. Rising airdumps lots of rain.

Found within a few

degrees near theequator

QuickTime™ and a TIFF (Uncompressed) decompressor are need ed to see this picture.

8/11/2019 08_EnvLife


Terrestrial Realm

• Deserts

– Dry trade winds

remove moisture

– 20 – 30° north and south

of the equator

– < 25 cm rain/year

– Little vegetation• Savannah, grasslands

– Too dry to support

forests

8/11/2019 08_EnvLife


Deserts • (<10 inches of

water per year)

develop under

the sinking dry

air masses andunder the dry

Trade Winds.

Usually foundaround 30°

latitude.


8/11/2019 08_EnvLife


Savannah Grasslands

• found between Rain forest

and Desert and receive

seasonal rain falls. Not

enough rain throughout the

year to support woodland

QuickTime™ and aT IFF (Uncompressed) decompressor are needed to see this picture.

QuickTime™ and aT IFF (Uncompressed) decompressor are needed to see this picture.

8/11/2019 08_EnvLife


Tundra

- Arctic ecosystem where

layer beneath soil remains

frozen throughout the year.

QuickTi me™ and a TIFF (Uncomp ress ed) decompress or are needed to see this picture.

QuickTime™ and a TIFF (Uncompressed) decompressor are nee ded to see this picture.

8/11/2019 08_EnvLife


Terrestrial Realm

• Poles

– Defined by ice sheets

and glaciers today

– Absent or reduced at

times in the past

8/11/2019 08_EnvLife


Terrestrial Realm

• Glaciers

– Ice in motion

– Glide and spread

– Present at high

latitudes and high

elevations near equator

8/11/2019 08_EnvLife


Terrestrial Realm

• Tundra

– Limited water

– Grasses, sedges, lichens,

shrubs dominate – Cannot support tall trees

• Evergreen coniferous

forests

– South of tundra – Spruce, pine, fir

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


Climate

• Altitude

– Similar to latitudinal

gradient

– At base

• Deciduous forest

– On slopes

• Evergreen forest

• Tundra above tree-line

– At top

• Glaciers

8/11/2019 08_EnvLife


Climate

• Mountains

• Rain shadow

– Prevailing winds bring

moisture• Precipitation on

windward side

• Aridity on leeward side

– Rain shadows common

on east side of NorthAmerican mountain

chains

8/11/2019 08_EnvLife


Climate

• Seasonal Change

– High heat capacity of

water

• Less change in oceantemperatures than on

land

• Monsoon Circulation

– Summer winds flowonshore; bring rain

– Winter winds offshore

8/11/2019 08_EnvLife


Plants as Climate Indicators

• Sensitive indicators of

change

– Cycads

• Tropics and subtropics

today

• Fossil distribution

allows reconstruction of

climate patterns

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


Marine Realm

• Ocean currents

– Wind driven

– Follow atmospheric patterns

• Trade winds

– Push waters west; formequatorial currents

– Equatorial countercurrents

• Return flow

• Gyres

– Clockwise in Northern

Hemisphere – Gulf Stream

8/11/2019 08_EnvLife


Marine Realm

• Circumpolar current

– Circles Antarctica

– Very cold

8/11/2019 08_EnvLife


Marine Realm

• Polar circulation

– Sea ice leads to more

saline water

– Cold, dense waters

sink

– Antarctic waters

• Flow north at depth

– Arctic waters

• Flow south at depth

8/11/2019 08_EnvLife


Marine Realm

• Ocean circulation

– Waves

• Surface waves

– Wind driven

– Break when seafloor interacts at shallow depths

– Tides

• Cause major movement of water in oceans

• Due to rotation of solid Earth beneath bulges ofwater produced by gravitational attraction of the

moon

8/11/2019 08_EnvLife


Marine Realm

• Continental Shelf

– Submarine extension of

continental landmass

• Shelf break – Edge of shelf

• ~200 m w.d.

• Continental Slope

• Continental Rise• Abyssal Plain

8/11/2019 08_EnvLife


Figure 4-31 (p. 131)Classification of marine environments.

( After Hedgspeth, UJ. W., ed. 1957. Treatise of Marine Ecology and Paleoecology. Geological Society

of America Memoirs 67(1): 18.)

8/11/2019 08_EnvLife


The Marine Realm • The depth of the Sea

• Moving from the beach seaward, one crosses a

consistent pattern of water depth changes. The

continental shelf extends from the shoreline to

the continental shelf break. Water depths over the

shelf vary from 0 to ~200 m. This environment is

very important for benthic communities because

the photic zone in the ocean extends only down to200m. Consider the implications for primary

production

8/11/2019 08_EnvLife


The Marine Realm

• The Shelf break marks the distal edge of

the shelf where seaward of this point, water

depths increase at a greater rate (3 to5°slope) compared with the shelf (1 to

2°slope).

8/11/2019 08_EnvLife


The Marine Realm

• Continental Slope.

• Typically, the slope extends down to 3000

to 3500 m. Near the base of the slope is thetransition from continental to oceanic crust.

8/11/2019 08_EnvLife


The Marine Realm

• The Slope gives way to the Continental

Rise. This is a less steep surface that

segways to the Abyssal Plain (the oceanfloor). The Rise is created as sediments are

transported down the slope in turbidity

currents.

8/11/2019 08_EnvLife


The Marine Realm

• At the base of the slope and out on theabyssal plain, the slope decreasessignificantly and the sediments are dropped,forming the Rise

8/11/2019 08_EnvLife


Figure 4-31 (p. 131)Classification of marine environments.

( After Hedgspeth, UJ. W., ed. 1957. Treatise of Marine Ecology and Paleoecology. Geological Society

of America Memoirs 67(1): 18.)

8/11/2019 08_EnvLife


Marine Realm

• Near shore

– Barrier islands

– Marshes

– Epicontinental seas

8/11/2019 08_EnvLife


Marine Realm

• Photic Zone

– Region of ocean where enoughlight penetrates to permit photosynthesis

• Pelagic life – Plankton

• Phytoplankton

• Zooplankton

– Nekton

• Benthic life

– Suspension feeders

– Deposit feeders

8/11/2019 08_EnvLife


Marine Realm

• Marine Biogeography

– Tropical

– Subtropical

– Transitional

– Subarctic

8/11/2019 08_EnvLife


Figure 4-36 (p. 135) Major ocean surface currents.

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife


Marine Realm

• Corals

– Most require warm water

– Common in tropics

• Reef builders – Coral polyp

– Builds coral cup

– Connected to other polyps

• Symbiotic relationshipwith algae

8/11/2019 08_EnvLife


Marine Realm

• Salinity

– Limiting factor near shore

– Oceanic

• 35 ppt – Brackish

• Lower than marine

• Bays, lagoons

– Hypersaline• Higher than marine

• Hot arid climates

8/11/2019 08_EnvLife


The portion of the temperature-depth curve in the

ocean that shows maximum change is the thermocline.

8/11/2019 08_EnvLife


Deep Water Circulation

8/11/2019 08_EnvLife


8/11/2019 08_EnvLife



• If we reverse the direction

and launch a rocket from

Panama towards

Washington DC, whichway will it curve?

• A = Right

• B = Left• C = Not at all because

Panama is close to the Eq.

08_EnvLife

Documents

Transcript of 08_EnvLife