EcologyEcology

Chapter 52

Ecology Ecology

52.1:Ecology Integrates Biological Research

Ecology: Interactions between organisms and their environment

BiosphereBiosphere

The biosphere is made up of systems that interact and are dependent on each other.

Includes all living and non living things Global ecosystem

◦All planet’s ecosystems

EcosystemEcosystemThe biosphere’s systems are called

ECOSYSTEMS.

All ecosystems must have a constant source of energy (usually the sun) and cycles or systems to reuse raw materials. ◦Examples: Water, Nitrogen and Carbon cycles.

An ecosystem is made up of all the biotic or living and the abiotic or non-living components in a given area.

PopulationPopulation

A population is all the members of a given species in a given area.

Example - All the turtles in a Lake.

CommunityCommunityCommunity - all the living things in an area

Example – Fish, algae, ducks, etc.

Ecological NicheEcological Niche

The niche describes the species' role or function within this community.

Niche and habitat are not the same. While many species may share a habitat,

this is not true of a niche.

Ecological Niche vs. HabitatEcological Niche vs. HabitatThe red fox's habitat, which might include a forest

is shared with many animals .

The niche of the red fox is that of a predator which feeds on small mammals, amphibians, insects, and fruit. Red foxes are nocturnal.

They are a host to blackflies and mosquitoes, and are host to numerous diseases.

The scraps, or carrion, left behind after a fox's meal provide food for many small scavengers and decomposers. This, then, is the ecological niche of the red fox.

Only the red fox occupies this niche in the meadow community.

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Organismal Ecology: Includes physiological, behavioral, and evolutionary biology Ex. How do penguins select a mate?

Population Ecology: The study of the size and composition of populations of organisms (one species) Ex. What factors affect reproduction of

mice? Community Ecology: The study of the

interaction between different species of organisms Ex. How does a fox’s population affect

the rabbit population?

Ecosystem Ecology: The study of biotic and abiotic factors in an ecosystem Ex. What factors affect the photosynthesis

of plants in a grassland?

Landscape Ecology: Ecology across adjacent ecosystems. Ex. What factors affect the dispersal of

animals in different ecosystems?

Ecological vs Evolutionary Effect •Farmer add pesticides to his crops to prevent insect infestation

•Ecological Effect

•Each year he must add more pesticides to obtain the same results.

• The pesticides has altered the gene pool of the insects-making them more resistant.

•Evolutionary Effect

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ent Behavioral adaptations are almost instantaneous in

their effects and are reversible Ex.

Physiological adaptations may be implemented and changed over time scales ranging from seconds to weeks Ex.

Morphological adaptations may develop over the lifetimes of individual organisms or between generations Ex.

Adaptive genetic changes in populations are slower still, usually evolving over several generations Ex.

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Population EcologyPopulation Ecology

Community EcologyCommunity Ecology

Ecosystem EcologyEcosystem Ecology

Landscape EcologyLandscape Ecology

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Principle of Allocation: "Each organism has a limited amount of energy that can be allocated for obtaining nutrients, escaping from predators, coping with environmental fluctuations, growth and reproduction.“

Conformers: Organisms whose internal environment conforms physically or chemical to its external environment Ex.

Regulators: Organisms whose internal environment does not conform to its external environment Ex.

Why regulate? Why Conform?

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Ecology and evolutionary biology are closely related sciences                                   

•Events that occur in the framework of ecological time (minutes, days, years) translate into effects over evolutionary time (decades, millennia).                                                •Example:  Hawks feeding on mice impact mouse population and may eventually lead to selection for mice with fur as camouflage.

52.2: Dispersal & Distribution of Species

•Dispersal- movement of organisms away from their origin or highly dense populations

•Natural Range Expansion shows the influence of dispersal on distribution

•Ex. Cattle Egret dispersed from Africa to South America

Abiotic FactorsAbiotic Factors

The nonliving things in an environment Includes Chemical & Physical aspects of

environment

Examples

-Sunlight -Temperature-Rainfall -Climate -Soil conditions -Nutrients

Biotic FactorsBiotic FactorsAll the living things or their materials that

directly or indirectly affect an organism in its environment.  

ExamplesOrganismsOrganisms’ wastes

Some Biotic Factors

-Parasitism -Disease -Predation -Symbiosis

Species dispersal contributes to the distribution of organisms                          Question: Is the distribution of a species limited by dispersal, i.e. by movement of the organisms?

Answer can be obtained by transplant experiments.

If the transplant is successful, then the organisms just haven’t reached the target area.

If the transplant is not successful, then other factors limit the distribution of the organisms, such as competitors, lack of a food source, etc.

Abiotic factors that affect Distribution                                   Temperature

-Affects biological processes-Ex. Many animals increase energy expenditure to regulate internal temperature

                                    Water

-Ex. Desert organisms have adaptations to store water -Ex. Camels’ humps, waxy leaf plants

Salinity-Osmoregulation of aquatic organisms

-Can either survive in fresh or salt water-but not both                                    

Sunlight-Main source of energy in ecosystems -Too much- May damage DNA and proteins (animals)-Too little- prevents photosynthesis (plants)

                                    Wind

-Increases heat & water loss                                    Rocks and soil

-pH and mineral composition

Abiotic factors that affect Distribution

Climate •Definition: Weather conditions of a particular area

What makes up climate?

1.Temperature 2.Precipitation

3.Sunlight4.Wind

Global Climate

•Dependent upon:1.Variations in reception of solar radiation due to a spherical earth; 2.The tilt of the earth’s axis as it rotates about the sun;3.The distribution of landmasses and oceans;4.Topography (landscape) features of the land.

Ocean currents•Ex. Gulf stream carries warm water from Equator- N. Atlantic

•Oceans and lakes- due to high specific heat

Mountains•Affect amount of sunlight reaching an area•South facing slopes in N. Hemisphere-receive more sun

•Warmer & drier •Affect precipitation •When warm moist air approaches a mtn, the air rises and cools

•Windward- rains•Leeward- dry conditions

•Cool air descends- produces “rain shadows”

Biotic factors that affect Distribution                        Pollinators

PreyPredators

 

  52.3: Aquatic biomesBiome: Terrestrial or aquatic life zones

Cover about 75% of the earth’s surface                        

• Wetlands

•Lakes

•Rivers, streams

•Coral reefs

•Oceans

 

                 

Stratification of Aquatic Biomes

•Photic zone- sufficient light for photosynthesis •Most plankon survive here

(photo= light)•Aphotic zone-light does not penetrate

•No photosynthesis•Minimal organisms

•Benthic- bottom of aquatic biome •Sandy •Organisms- benthos feed on detritus (dead organic matter)

•Abyssal zone- Very deep part of ocean •Very cold and high water pressure•Absent of light•Low nutrients (Abyss)=deep

•Intertidal zone-shallow zone of ocean that meets land•Often polluted by oil that decreases biodiversity.(Inter= between)

Marine environment with zonation.

Rivers and Streams

•Environment: Currents •Organisms: Require adaptations so that they are not swept away by moving water

•Human Impact: Changing the course of flow •Ex- dams and channels

Oligotrophic Lakes

• Nutrient: Poor, rich in oxygen•Organisms: Min. algae, minimal phytoplankton•Environment: Deep with little surface area.

(Oligo =small/scant)

Eutrophic lake

•Nutrient : Rich, oxygen poor •Organisms: Algae •Human impact: Fertilizers(Eu =good/well)

Check Point

What type of lake is rich in nutrients?

Check Point-Answers

What type of lake is rich in nutrients?

Eutrophic lakes

Wetlands

•Ex’s: Marshes, bogs, swamps, seasonal ponds. •Among richest biomes with respect to biodiversity and productivity.

• Human Impact: Wastelands.

Estuary

•Transition of freshwater stream or river merges with the ocean. •Organisms: Highly productive biome•Human Impact: Polluted from river input so many fisheries are now lost.

(Estuar= the sea)

Coral Reefs

•Warm, tropical water•Organisms: Cnidarians (corals)

•Rich biodiversity

•Human Impact: Global temperature changes

Deep-sea vent

Occurs in benthic zone•Organisms: Unusual organisms

•Chemotrophs•Energy comes not from light but from chemicals released from the magma.

52.4: Terrestrial biomes                       

Important Feature- Vertical layering

•Canopy- upper layer•Shrubs•Forest floor (litter layer )•Root layer

                        

Tropical Forest

•Features: Vertical stratification •Canopy blocking light to bottom strata.

•Distribution: Equatorial regions•Organisms: Most diverse

•Epiphytes (plants that grow on other plants)•Climate: Little variation-warm

Desert

•Distribution- 30o N & S•Climate: Seasonal and daily variations

•< 30 cm per year •Can be either very, hot, or very cold (e.g. Antarctica)

•Organisms: succulents (ex. cacti)•Plants

•Adaptations: desiccation tolerance •Plants-CAM or C4

•Animals: most nocturnal , water conservation

Chaparral

•Distribution: mid latitudinal coastal regions •Ex. Spain & Chile, California

•Climate: mild rainy winters; long, hot, dry summers•Organisms:

•Plants: Diverse- small trees, shrubs, grasses •Fire adaptations-fire resistant roots

•Animals: browsers (ie. Deer & goats)•Periodic fires, some plants require fire for seeds to germinate.

Temperate Grassland (Praries)

Distribution: S. Africa, Argentina, N. Dakota•Features: Seasonal drought and fires•Climate: Dry cold winters & wet summers •Organisms:

•Animals- Large grazing animals (Bison) & burrowing animals (prairie dogs)•Plants: grasses-drought resistant

•Very little prairie exists in US today.

Temperate Deciduous Forest (Broadleaf)

•Distribution: Mid-latitudes •Ex’s: Australia , N. Carolina•Climate: moderate rain, cold winters, hot summers •Organisms:

•Plants: Deciduous trees- drop leaves before winter •Vertical strata: trees

•Animals: hibernate & migrate in winter Original forests lost from North America by logging and clearing.

Coniferous forest (Taiga)•Distribution: North America •Climate: long cold winters, hot summers•Organisms:

•Plants- cone-bearing (pine, fir)•Animals: hibernate & migrate

•Ex’s bears, moose•Largest terrestrial biome on earth

Tundra

•Distribution: Arctic, Alaska •Alpine tundra- high mountain tops-even in tropics

•Climate: Long cold winters, short moderate summers•Permafrost (Permanent frozen ground)

•Organisms:•Plants: mosses, grasses, lichens, min. trees•Animals: Large grazers, caribou

•Migrate & hibernate•Source of oil

Define the Biome based on the characteristics below:

1.Warm temperatures year round with rich biodiversity

2. Minimal rain fall, scattered vegetation, daily temperature fluctuations

3. Plants have fire-resistant adaptations

4. Very cold long winters with much precipitation

5. Cone-bearing trees

Answers: Define the Biome based on the characteristics below:

1.Warm temperatures year round with rich biodiversityTropical Forests

2. Minimal rain fall, scattered vegetation, daily temperature fluctuationsDesert

3. Plants have fire-resistant adaptationsChaparral

4. Very cold long winters with much precipitationTundra

5. Cone-bearing trees Coniferous forest (taiga)