Ecology

The interaction of an organism and its environment

Biology is multidimensional

CellTissueOrgan

Organ SystemOrganismPopulationCommunityEcosystem

This array is an example of what dimension?Levels of Organization

What fields of biology are at each extreme?Biochemistry and Biophysics

In this course our focus will be upon…The Plant!

Ecosphere

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What is the white mass at the top?

What is the big green-brown body in the upper half?

What season is it in Connecticut?

What are the white swirls?

Where is the equator?

Biome: deciduous forest biome

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What is one source for the water?

Ecosystems: forest, riverine, old field, disturbed

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Forest ecosystem: a community of trees

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What are the different colors and shapes?What are we not seeing without a closer look?

Forest Community: What do producer, consumer, decomposer mean?

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Population of trees--OK only if ONE species? Is that valid?

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Organism: one tree

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Why is this one tree so

different from those

individuals in the previous

picture?

Organ System: branch with stem, buds, petioles, leaves

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Organ: one leaf

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Tissues: epidermis, palisade and spongy mesophyll, xylem, phloem

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epidermiswindow, lens

palisade mesophyllphotosynthesis

xylemwater and mineral intake

phloemsugar and amino acid export

spongy mesophyllevaporative cooling (photosynthesis)

epidermisregulates water loss and gas exchange

Cell: a mesophyll protoplast (Cell wall was digested off by cellulase)

http://www.botany.wisc.edu/images/mesophyll-protoplast_lg.jpg

cell membraneimport/export

chloroplastphotosynthesis

cytosolfermentation glycolysis

vacuoletoxic waste processing

nucleustranscriptionreplication

Organelles: endoplasmic reticulum, nucleus, mitochondrion, oleosome

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endoplasmic reticulum

internal transport

nucleustranscription, replication

mitochondrionrespiration

zymogen granule enzyme protein storage

and secretion compartment

DNA

Macromolecular: DNA

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nitrogenous bases(blue green white red)

Environmental Requirements For Plants

Water (H2O)

Carbon Dioxide (CO2)

Sunlight and Heat

Minerals (most from soil)

Macroelements (above plus:)

N=nitrogen P=phosphorus K=potassium

Ca=calcium Mg=magnesium

Fe=iron S=sulfur

Microelements (enzyme cofactors)

Co Mn Cu Zn Si Mo B Al Cl

Forest Community Trophic Levels: What do producer, consumer, decomposer mean?

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Food Web and Trophic Pyramid

2° Carnivores 10 kcal m-2 yr-1

1° Carnivores 400HerbivoresHerbivores 4,000Producers 21,000

energy processed

Energy lost at each transition and with “life cost” at each level

Food Web and Trophic Pyramid

1° Carnivores 0.1 g DW m-2

HerbivoresHerbivores 0.6Producers 470.0

biomass

plants outweigh all consumers combined!

Food Web and Trophic Pyramid

ZooplanktonZooplankton 21g DW m-2

Phytoplankton 4

biomassWhich trophic level has the higher rates of growth and/or reproduction?

What happens if I use “weed and feed” on my lawn?

Food Web and Trophic Pyramid

2° Carnivores1° CarnivoresHerbivoresHerbivoresProducers

population size

This might be expected for a grasslands ecosystem

Food Web and Trophic Pyramid

2° Carnivores1° CarnivoresHerbivoresHerbivoresProducer

population size

This might be expected for a tropical single-tree ecosystem

What is the compensating factor making this stable?

If the tree is unique in a very diverse tropical rainforest, if the associated species have obligate relationships, what happens if we “harvest” this one tree?

Spirodela http://www.univ-ubs.fr/ecologie/Photos/lemna.jpg

Lemna http://www.mobot.org/jwcross/duckweed/Lemna_graphics_New/L_gibba2.jpg

Competition:

Spirodela is excluded by Lemna when grown together

Did/Will you observe competitive exclusion in the arboretum?

Allelopathy: chemical inhibition of other organisms nearby.

Symbiosis: Mutualism

Legume - Rhizobium

Pollinator - Flowering plant

Ant - Acacia

Trees - Mycorrhizal fungi

Lichen

http://faculty.vassar.edu/suter/1websites/osawa/photography/images/lichenfoliose.jpg

Symbiosis: Commensalism

Tree - Vitis labrusca

http://www.all-creatures.org/pica/ftshl-grape-24.jpg

Symbiosis: Parasitism

Vitis labrusca - Phylloxera infestans

http://ohioline.osu.edu/b919/images/919_080.jpg

Symbiosis: HerbivoryUngulate or Rodent - Plant

Opuntia - Cactoblastis cactorum - Cyclura rileyi

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Symbiosis: CarnivoryCarnivorous plant - Animal

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Succession: PrimaryPioneer Species colonizing rock, creating soil

Succession: SecondarySuccessional Seres: Old Field going back to Forest

http://www.freewebs.com/kingsprovince/Old%20field.jpg

Is a Climax Community a valid concept? (Chestnut, Dogwood)

Tropical Climate

The sun passes directly overhead for more days per year than anywhere else

Minimal photoperiod swings

The sun passes directly overhead only one day per year

Photoperiod swings

The sun fails to rise at least one day per year

Extreme photoperiod swings

Terrestrial Landmarks and Photoperiod Swings

Effect of Latitude and Solar Incidence

Effect of Latitude, Longitude (proximity to water)

How harsh is the winter in Willimantic, Connecticut?

Effect of Latitude • The thin white line around the earth is its atmosphere!

• Air pockets called “cells” have the circulation indicated by arrows.

• ArrowsArrows coming down indicate high pressure, less precipitation.

• ArrowsArrows pointing outward indicate low pressure, and high precipitation.

• Pattern repeated in Southern Hemisphere (not shown)

L

westerlies

horse latitudesSE trade winds

NE trade winds

equatorial doldrums

westerlieshorse latitudes

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30°S

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LH

Effect of Elevation

Biomes on Earth

Biome Temperature Precipitation Key Plants Other Features

Rainforest High HighBroadleaf evergreen trees, epiphytes, lianas (vines)

The soils are infertile and the species diversity is very high

Savannas and Deciduous

Tropical ForestHigh

Seasonal Drought

Grasslands with scattered broadleaf deciduous shrubs

and trees

Periodic fire is common, C4 photosynthesis

Desert HighLow but a

"wet" seasonSucculents and some annual

herbs

Small/no leaves, thick waxy cuticles, hairy epidermi, CAM

photosynthesis

Grasslands Temperate Moderate LowPerennial bunch and sod

grassesLand exploited for crops

Temperate deciduous

forestTemperate Moderate Even

Deciduous trees and perennial herbs

Obvious herbaceous plants vary with season

Temperate mixed and

conifer forestsModerate Moderate

Mixtures of broadleaf and conifers

Transition between temperate and taiga, soils are infertile

Mediterranean scrub

Temperatemoist winter dry summer

Evergreen and summer deciduous trees and shrubs,

thicket/coppice

Also known as chaparral (NW) and maquis (OW)

Taiga Severe temperate Moderate Low Coniferous forestSoils are acid and infertile,

possible permafrost

Tundra Extreme temperate LowVery low shrubs, grasses,

lichens, herbs

Permafrost present in soil, much plant biomass is below

ground