introduction to ecology - slhs ap biology · . abiotic and biotic interactions 13

Introduction to Ecology

Ecology derives components from each of the Four Big Ideas in Biology

Big Idea 1: The process of evolution drives the diversity and unity of life

Big Idea 2: Biological systems utilize free energy and molecular building blocks to grow to reproduce & to maintain dynamic homeostasis

Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes

Big Idea 4: Biological systems interact, and these systems and their interactions possess complex properties.

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Ecology Defined

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3

Ecology isthe study of organisms and their interactions with the environment.

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Levels of Organization

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Types of Ecology

Ecologist use observations & experiments to test explanations for distributions and abundance of species.

1. Organismal ecology is the study of physiology and behavior interacting with environmental challenges

2. Population ecology studies the factors impacting the number of individuals of a species in an area

3. Community ecology is the study of how organisms interact with each other and the environment

4. Ecosystem ecology studies the energy flow and chemical cycling in a given area

Types of Ecology

Identify the category of ecological research that would investigate each of the following questions.

1. How do trout select a mate?

(A)Organismal ecology

(B)Population ecology

(C) Community ecology

(D)Ecosystem ecology

Types of Ecology


2. What factors control photosynthetic productivity in a tropical rainforest?





Types of Ecology


3. What factors influence the diversity of species that make up a rain forest?





Abiotic and Biotic Interactions: The 1st Law of Thermodynamics

12http://www.sci.uidaho.edu/scripter/geog100/lect/16-ecosystems-biomes/ecosystems-files/ecosystems.htm

Abiotic and Biotic Interactions


Importance of Abiotic Factors

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Not every organism can live everywhere on Earth

Abiotic factors determine which organisms can survive where:

The Coral Reef is an environment teeming with life, but many organisms would find this environment unsuitable due to its abiotic factors (too much water, temperature, availability of light, etc. )

Importance of Biotic Factors

W. J. Fletcher tested the effects of two algae-eating animals, sea urchins and limpets, on seaweed abundance near Sydney, Australia. In areas adjacent to a control site, either the urchins, the limpets, or both were removed.

EXPERIMENT

80

60

40

20

0

Limpet

Seaurchin

Both limpetsand urchinsremoved

Onlyurchinsremoved

Only limpets removed

August1982

February1983

August1983

February1984

Control (bothurchins andlimpets present)

Seaw

eed

co

ver

(%)

Removing bothlimpets andurchins orremoving onlyurchins increasedseaweed coverdramatically.

Almost noseaweed grewin areas whereboth urchins andlimpets werepresent, or whereonly limpets wereremoved.

Seaw

eed

co

ver

(%)

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Macroclimateconsists of patterns on the global, regional, and landscape level

Microclimate consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log

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Earth’s Climate Varies By Latitude & Season

And Is Changing Rapidly

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•Seasonal variations of light and temperature increase steadily toward the poles

•Seasonality at high latitudes is caused by the tilt of Earth’s axis of rotation and its annual passage around the sun

•Belts of wet and dry air straddling the equator shift throughout the year with the changing angle of the sun

•Changing wind patterns affect ocean currents

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• Global Climate Change• Changes in Earth’s climate can profoundly

affect the biosphere

• One way to predict the effects of future global climate change is to study previous change

• As glaciers retreated 16,000 years ago, tree distribution patterns changed

• As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct

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Homeostasis

• Organisms must maintain homeostasis, a steady-state internal environment, despite changes in the external environment.

• Organisms respond to abiotic factors in 1of 2 ways:

1. Regulators maintain a nearly constant internal environment, despite external conditions

2. Conformers allow internal environment to vary- This occurs in organisms whose environments remain relatively stable

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EURASIA

AFRICA

SOUTHAMERICA

INDIA

135 million years ago

Present65 million years ago

225 million years ago

120°80° 0°

120°120°

120°

80°80° 80°80°40°

40°120° 120°

120°

GONDWANALANDGONDWANALAND

120°

LAURASIALAURASIA

ANTARCTICAANTARCTICA

AUSTRALIAAUSTRALIA

NORTH AMERICANORTH AMERICA

MADA-GASCAR

MADA-GASCAR

Historical Biogeography

Biogeography: Leopard Distribution

Biogeography: Leopard Distribution

• Leopards have the largest distribution of any wild cat, occurring widely in eastern and central Africa, although populations have shown a declining trend and are fragmented outside of sub-Saharan Africa.

• Within sub-Saharan Africa, the species is still numerous and even thriving in marginal habitats where other large cats have disappeared.

• But populations in North Africa may be extinct

Biogeography

• Serves as a starting point to understanding limits on distribution of species

Species absentbecause

Yes

No

Dispersallimits

distribution?

Yes

No

Yes

No

Biogeography & Distribution of Species



Yes

No

Dispersallimits

distribution? Behaviorlimits

distribution?

Yes

No

Yes

No

Area inaccessibleor insufficient time

Biogeography



Yes

No

Dispersallimits


distribution? Biotic factors(other species)

limitdistribution?

Yes

No

Yes

No


Habitat selection

Biogeography



Yes

No

Dispersallimits


distribution? Biotic factors(other species)

limitdistribution? Abiotic factors

limitdistribution?

Yes

No

Yes

No


Habitat selection

Predation, parasitism,competition, disease

Biogeography



Yes

No

Dispersallimits


distribution?Biotic factors

(other species)limit

distribution?Abiotic factors

limitdistribution?

Yes

No

Yes

No


Habitat selection

Predation, parasitism,competition, disease

WaterOxygenSalinitypHSoil nutrients, etc.

TemperatureLightSoil structureFireMoisture, etc.

Chemicalfactors

Physicalfactors

Ecology: The Big Picture

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1. Biological systems interact, and these systems and their interactions possess complex properties.

2. Abiotic and biotic factors influence populations, communities, ecosystems, and the biosphere.

3. Over time species have adapted, died, or moved to more suitable environments.

introduction to ecology - slhs ap biology · . abiotic and biotic interactions 13

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