AP Biology


Ecology

Is the scientific study of the interactions between organisms and the environment

These interactions

Determine both the distribution of organisms and their abundance
 Where organisms are found and how many of them there are
AP Biology


Ecology

Both observational/descriptive and experimental
 Observing what’s there and seeing how it changes
 Rigorous - mathematical modeling of populations and ecosystems

Ecological time

Minute-to-minute interactions

Compare to evolutionary time
AP Biology


Abiotic factors
 non-living chemical & physical factors
 Temperature
 Light
 Water, including salinity
 Nutrients, including soil and rocks
 Dissolved oxygen!

Biotic factors
 living components
AP Biology 2005-2006


Affect the distribution and abundance of organisms
Kangaroos/km 2
> 20
10 –20
5 –10
1 –5
0.1
–1
< 0.1
Limits of distribution
Climate in northern Australia is hot and wet, with seasonal drought.
Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year.
Southeastern Australia has a wet, cool climate.
Southern Australia has cool, moist winters and warm, dry summers.
Tasmania
AP Biology

The figure below (Figure 52.5 in the textbook) shows the distribution of red kangaroos in Australia. From this figure, you can predict that kangaroos: a.
b.
c.
d.
e.
eat plants prefer a hot dry climate don’t like saltwater prefer to live in areas where people don’t live are more abundant in some years than in other years
Kangaroos/km 2
> 20
10 –20
5 –10
1 –5
0.1
–1
< 0.1
Limits of distribution
Climate in northern Australia is hot and wet, with seasonal drought.
Southern Australia has cool, moist winters and warm, dry summers.
Tasmania
Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year.
Southeastern Australia has a wet, cool climate.
AP Biology


Dispersal - the movement of individuals away from their area of origin or from centers of high population density

Natural range expansion
 Early humans “out of Africa”
 Different from migration

Species transplants
 Potential vs. actual ranges

Where organisms could be versus where they are

Invasive/introduced species
AP Biology

AP Biology 2005-2006


Climate - Long-term prevailing weather in a particular area

Macroclimate - Patterns on a global, regional and local level

Microclimate - Patterns on a smaller scale
 Ex. A community living under a log
Lichen Rotting Logs Tide Pools
AP Biology 2005-2006


Latitudinal variation in sunlight intensity
AP Biology

Seasonal variation in sunlight intensity
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Global air circulation and precipitation patterns.
AP Biology


Global wind patterns

Currents and other bodies of water
AP Biology


Mountains and elevation
AP Biology

benthos coral reef intertidal
AP Biology

30

N
Tropic of
Cancer
Equator
Tropic of
Capricorn
30

S
Continental shelf benthos
Key
Lakes
Coral reefs
Rivers
Oceanic pelagic zone intertidal
AP Biology
Estuaries
Intertidal zone
Abyssal zone
(below oceanic pelagic zone) coral reef


Account for the largest part of the biosphere in terms of area

Can contain fresh (aquatic), brackish, or salt (marine) water

Oceans

Cover about 75% of Earth’s surface

Have an enormous impact on the biosphere
AP Biology


Are stratified into zones or layers defined by light penetration, temperature, and depth

Thermoclines Intertidal zone - Narrow vertical zone of
Neritic zone Oceanic zone abrupt temperature change. zone
Limnetic zone
0
200 m
Continental shelf
Photic zone
Pelagic zone
Benthic zone
Photic zone
Aphotic zone
Benthic zone
Pelagic zone
Aphotic zone
2,500
–6,000 m
Abyssal zone
(deepest regions of ocean floor)
(a)
Zonation in a lake. Based on light penetration, distance from short and water depth, and open water or bottom.
(b) Marine zonation.
Like lakes, the marine environment is generally classified on the basis of light penetration (photic and aphotic zones), distance from shore and water depth (intertidal, neritic, and oceanic zones), and whether it is open water (pelagic zone) or bottom (benthic and abyssal zones).
AP Biology

1

Lakes and other marine/aquatic biomes experience turnover
2
In spring, as the sun melts the ice, the surface water warms to 4 °C
In winter, the coldest water in the lake (0 °C) lies just below the surface ice; water is progressively warmer at deeper levels of the lake, typically 4 –5°C at the bottom.
and sinks below the cooler layers immediately below, eliminating the thermal stratification. Spring winds mix the water to great depth, bringing oxygen (O
2
) to the bottom waters (see graphs) and nutrients to the surface.
Spring O
2
(mg/L)
0 4 8
Winter
0
O
2
(mg/L)
4 8 12 12
8
16
24
4

C
4

4

4

2

0

4

C
4

4

4

4

4

O
2 concentration
High
Medium
Low
8
16
24
8
16
24
O
2
(mg/L)
0 4 8 12
Autumn
AP Biology underlying layers, remixing the water until the surface begins to freeze and the winter temperature profile is reestablished.
4

4

C
4

4

4

4

O
2
(mg/L)
0 4 8 12
Thermocline
4

C
5

6

8

20

18

22

Summer
8
16
24
3
In summer, the lake regains a distinctive thermal profile, with warm surface water separated from cold bottom water by a narrow vertical zone of rapid temperature change, called a thermocline.


Oligotrophic nutrient poor, oxygen rich

Eutrophic - nutrient rich, oxygen poor

Periodic oxygen depletion; large amount of decomposition

Biota - fish, invertebrates depending on O
2 levels, phyto- and zooplankton
An oligotrophic lake in
Grand Teton, Wyoming
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LAKES
A eutrophic lake in Okavango delta, Botswana


Inundated with water at least periodically

Plants adapted to water-saturated soil

Highly productive

Important filters and breeding grounds

Birds, carnivores, crustaceans, plants, reptiles
WETLANDS
Okefenokee National Wetland Reserve in Georgia
AP Biology


Current with lots of aeration

Aquatic plants and phytoplankton, fish, invertebrates, etc.

Ex. Potomac and
Anacostia rivers,
Rock and Sligo creeks, Chesapeake
Bay watershed
STREAMS AND RIVERS
AP Biology
Figure 50.17
A headwater stream in the
Great Smoky Mountains
The Mississippi River far form its headwaters


Transition between rivers and sea - brackish water with flow between the two

Variable salinity depending on temperature, depth, and tides

Worms, oysters, crabs, fish, etc.

Highly productive and important in filtering water
ESTUARIES
Figure 50.17
An estuary in a low coastal plain of Georgia
AP Biology


Periodically submerged and exposed

Physical environment varies vertically, so species range varies vertically

Oxygen and nutrients renewed tidally

Sea grass, algae, worms, crustaceans, crabs, etc.
INTERTIDAL ZONES
Figure 50.17
Rocky intertidal zone on the Oregon coast
AP Biology

OCEANIC PELAGIC BIOME
Figure 50.17
Open ocean off the island of Hawaii

Open ocean, particularly deep water

Driven by currents - lots of light and oxygen; large photic zone

Experience nutrient turn over - depends on temperature
 70 percent of world’s surface

Phytoplankton and photosynthetic bacteria - makes our oxygen!

Zooplankton, fish, cephalopods, marine mammals, etc.
AP Biology


Formed from coral
“skeletons”

Photic zone - zooxanthellae need light for
CORAL REEFS photosynthesis; sensitive to change in temperature

Fringing reef --> barrier reef
--> atoll island

Unicellular algae, coral animals, fish and invertebrate diversity
Figure 50.17
A coral reef in the Red Sea
AP Biology


Below neritic (near,
MARINE BENTHIC ZONE coastal) and pelagic
(noncoastal, open water) zones

Deep benthic = abyssal zone; deep sea vents with chemoautotrophs

Shallow benthic - oxygen from algae and seaweed

Chemo- or photoautotrophs; worms, arthopods, echinoderms, etc.
A deep-sea hydrothermal vent community
AP Biology

distribution: equatorial precipitation: very wet temperature: always warm characteristics: many plants & animals, thin soil
AP Biology

distribution: equatorial precipitation: seasonal, dry season/wet season temperature: always warm characteristics: fire-adapted, drought tolerant plants; herbivores; fertile soil
AP Biology 2005-2006

distribution: 30 °N & S latitude band precipitation: almost temperature: variable daily & seasonally, hot & cold characteristics: sparse vegetation & animals, cacti, succulents, drought tolerant, reptiles, insects, rodents, birds
AP Biology 2005-2006

distribution: mid-latitudes, mid-continents precipitation: seasonal, dry season/wet season temperature: cold winters/hot summers characteristics: prairie grasses, fire-adapted, drought tolerant plants; many herbivores; deep, fertile soil
AP Biology 2005-2006

distribution: mid-latitude, northern hemisphere precipitation: adequate, summer rains, winter snow temperature: moderate warm summer/cool winter characteristics: many mammals, insects, birds, etc.; deciduous trees; fertile soils
AP Biology 2005-2006

distribution: high-latitude, northern hemisphere precipitation: adequate to dry (temperate rain forest on coast) temperature: cool year round
2005-2006

distribution: arctic, high-latitude, northern hemisphere precipitation: dry temperature: cold year round characteristics: permafrost, lichens & mosses, migrating animals
2005-2006

distribution: high elevation at all latitudes precipitation: dry temperature: cold year round characteristics: permafrost, lichens, mosses, grasses; migrating
2005-2006