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Chapter 52
An Introduction to Ecology
and the Biosphere
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Ecology interactions between
organisms and the
environment
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 52-2
Organismal
ecology
Population
ecology
Community
ecology
Ecosystem
ecology
Landscape
ecology
Global
ecology
Fig. 52-6
Biogeography - good starting point for understanding
what limits geographic distribution of species
Why is species X absent
from an area?
Yes
Does dispersal
limit its
distribution?
No
Area inaccessible
or insufficient time
Does behavior
limit its
distribution?
Yes
Habitat selection
Yes
No
Do biotic factors
(other species)
limit its
distribution?
No
Predation, parasitism, Chemical
competition, disease factors
Do abiotic factors
limit its
distribution?
Water
Oxygen
Salinity
pH
Soil nutrients, etc.
Temperature
Physical Light
factors Soil structure
Fire
Moisture, etc.
Two kinds of factors that determine distribution: biotic,
or living factors, and abiotic, or nonliving factors
Dispersal and Distribution
• Dispersal - movement of individuals away from
centers of high population density or from their
area of origin
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Fig. 52-7
Natural range
expansions
show the
influence of
dispersal on
distribution
Current
1970
1966
1965
1960
1961
1943
1958
1951
1956
1970
1937
Species Transplants
• Species transplants include organisms that are
intentionally or accidentally relocated from their
original distribution
• Species transplants can disrupt the
communities or ecosystems to which they have
been introduced
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Behavior and Habitat Selection
• Some organisms do not occupy all of their
potential range
• Species distribution may be limited by habitat
selection behavior
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Biotic and Abiotic Factors
• Biotic factors that
affect the distribution
of organisms may
include:
– Interactions with other
species
– Predation
– Competition
• Abiotic factors
affecting distribution
of organisms include:
– Temperature
– Water
– Sunlight
– Wind
– Rocks and soil
• Most vary in space
and time
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Temperature
• Environmental temperature is an important
factor in distribution of organisms because of
its effects on biological processes
• Cells may freeze and rupture below 0°C, while
most proteins denature above 45°C
• Mammals and birds expend energy to regulate
their internal temperature
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Water
• Water availability in habitats is another
important factor in species distribution
• Desert organisms exhibit adaptations for water
conservation
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Salinity
• Salt concentration affects water balance of
organisms through osmosis
• Few terrestrial organisms are adapted to highsalinity habitats
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Sunlight
• Light intensity and quality affect photosynthesis
• Water absorbs light, thus in aquatic
environments most photosynthesis occurs near
the surface
• In deserts, high light levels increase
temperature and can stress plants and animals
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Rocks and Soil
• Many characteristics of soil limit distribution of
plants and thus the animals that feed upon
them:
– Physical structure
– pH
– Mineral composition
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Climate
• Four major abiotic components of climate are
temperature, water, sunlight, and wind
• The long-term prevailing weather conditions in
an area constitute its climate
• Macroclimate consists of patterns on the
global, regional, and local level
• Microclimate consists of very fine patterns,
such as those encountered by the community
of organisms underneath a fallen log
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Global Climate Patterns
• Global climate patterns are determined largely by solar
energy and the planet’s movement in space
• Sunlight intensity plays a major part in determining the
Earth’s climate patterns
• More heat and light per unit of surface area reach the
tropics than the high latitudes
• Seasonal variations of light and temperature increase
steadily toward the poles
• Global air circulation and precipitation patterns play major
roles in determining climate patterns
• Warm wet air flows from the tropics toward the poles
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 52-10a
Latitudinal Variation in Sunlight Intensity
90ºN (North Pole)
60ºN
Low angle of incoming sunlight
30ºN
23.5ºN (Tropic of
Cancer)
Sun directly overhead at equinoxes
0º (equator)
23.5ºS (Tropic of
Capricorn)
30ºS
Low angle of incoming sunlight
60ºS
90ºS (South Pole)
Atmosphere
Seasonal Variation in Sunlight Intensity
60ºN
30ºN
March equinox
0º (equator)
June solstice
30ºS
Constant tilt
of 23.5º
September equinox
December solstice
Fig. 52-10d
Global Air Circulation and Precipitation Patterns
60ºN
30ºN
Descending
dry air
absorbs
moisture
0º (equator)
30ºS
60ºS
30º 23.5º
Arid
zone
Ascending
moist air
releases
moisture
0º
Tropics
Descending
dry air
absorbs
moisture
23.5º 30º
Arid
zone
Global Wind Patterns
66.5ºN
(Arctic Circle)
60ºN
Westerlies
30ºN
Northeast trades
Doldrums
Southeast trades
0º
(equator)
30ºS
Westerlies
60ºS
66.5ºS
(Antarctic Circle)
Fig. 52-12
2 Air cools at
3 Cooler
high elevation.
air sinks
over water.
1 Warm air
over land rises.
4 Cool air over water
moves inland, replacing
rising warm air over land.
Fig. 52-13
•Mountains have a
significant effect on
•Amount of sunlight
reaching an area
•Local temperature
•Rainfall
Wind
direction
Leeward side
of mountain
Mountain
range
Ocean
Fig. 52-16
Many aquatic biomes are stratified into zones or layers
defined by light penetration, temperature, and depth
Intertidal zone
Oceanic zone
Neritic zone
Littoral
zone
Limnetic
zone
0
Photic zone
200 m
Continental
shelf
Benthic
zone
Photic
zone
Benthic
zone
Pelagic
zone
Aphotic
zone
Pelagic
zone
Aphotic
zone
2,000–6,000 m
Abyssal zone
Photic zone (photosynthesis) and aphotic zone (little light)
Benthic zone - organic and inorganic sediment at the bottom of all aquatic
Benthos - communities of organisms
Detritus - dead organic matter; important source of food
Fig. 52-17-5
Thermocline separates the warm upper layer
from the cold deeper water
Turnover - semiannual mixing of their waters
mixes oxygenated water from the surface with
nutrient-rich water from the bottom
Winter
Summer
Spring
2º
4º
4º
4º
4ºC
0º
4º
4º
Autumn
20º
18º
8º
6º
5º
4ºC
4º
4º
4º
4ºC
Thermocline
22º
4º
4º
4º
4º
4ºC
4º
Major aquatic biomes can be characterized by their physical
environment, chemical environment, geological features,
photosynthetic organisms, and heterotrophs
Oligotrophic lakes - nutrient-poor and generally oxygen-rich
Eutrophic lakes - nutrient-rich and often depleted of oxygen
if ice covered in winter
Wetland - inundated by water at least some of the time
– supports plants adapted to water-saturated soil
– among the most productive biomes on earth
Streams and Rivers
–
most prominent physical characteristic is current
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• Estuary
– transition area between river and sea
– Salinity varies with the rise and fall of the tides
– nutrient rich and highly productive
• Intertidal zone
– periodically submerged and exposed by the
tides
– challenged by variations in temperature and
salinity and mechanical forces
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Concept 52.4: The structure and distribution of
terrestrial biomes are controlled by climate and
disturbance
• Climate is very important in determining why
terrestrial biomes are found in certain areas
• Biome patterns can be modified by
disturbance such as a storm, fire, or human
activity
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Fig. 52-19
Tropical forest
Savanna
Desert
30ºN
Tropic of
Cancer
Equator
Tropic of
Capricorn
30ºS
Chaparral
Temperate
grassland
Temperate
broadleaf forest
Northern
coniferous forest
Tundra
High mountains
Polar ice
Climate and Terrestrial Biomes
• Climate has a great impact on the distribution
of organisms
• This can be illustrated with a climograph, a
plot of the temperature and precipitation in a
region
• Biomes are affected not just by average
temperature and precipitation, but also by the
pattern of temperature and precipitation
through the year
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 52-20
Annual mean temperature (ºC)
Desert
Temperate grassland
Tropical forest
30
Temperate
broadleaf
forest
15
Northern
coniferous
forest
0
Arctic and
alpine
tundra
–15
0
100
200
400
300
Annual mean precipitation (cm)
General Features of Terrestrial Biomes and the
Role of Disturbance
• Terrestrial biomes are often named for major
physical or climatic factors and for vegetation
• Terrestrial biomes usually grade into each
other, without sharp boundaries
• The area of intergradation, called an ecotone,
may be wide or narrow
• Layering of vegetation in all biomes provides
diverse habitats for animals
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings