Chapter 51 summary
LDM103
Ecology is a rigorous experimental science that requires a breadth of biological
knowledge. Ecologist observe nature, generate hypotheses, manipulate
environmental variables and observe outcomes.
Concept 51.1
The most significant influence on the distribution organisms on land and in the
ocean is climate the long-term prevailing weather conditions in a given area.
Climate at two scales: - Macroclimate patterns on the global, regional, and
landscape level.
- Microclimate very fine, localized patterns.
Global climate patterns are determined largely by the input of solar energy and
earth’s movement in space.
Climate patterns include seasonal variation and can be modified by other factors
(such as large bodies of water and mountain ranges).
In addition to these global changes day length, solar radiation, and temperature,
the changing angle of the sun over the course of the year affects local
environments.
Ocean currents influence climate along the coasts of continents by heating or
cooling overlying air masses that pass across the land. Because of the high
specific heat of water oceans and large lakes tend to moderate the climate of
nearby land.
Mountains also influence air flow over land warm air approaches a mountain,
the air rises and cools. Cooler, dry air descends, absorbing moisture and
producing a “rain shadow”.
Mountains also affect the amount of sunlight reaching an area and thus the local
temperature and rainfall.
Many features in the environment influence microclimate by casting shade,
altering evaporation form soil, or changing wind patterns. Every environment on
Earth is characterized by a mosaic of small-scale differences in chemical and
physical attributes, such as temperature, light, water, and nutrients. These
abiotic , or nonliving, factors influence the distribution and abundance of
organisms.
Because climate variables affect the geographic ranges of most plants and
animals, any large-scale change in Earth’s climate profoundly affects the
biosphere. as example: the burning of fossil fuels and deforestation are
increasing the concentrations of carbon dioxide and other greenhouse gases in
the atmosphere.
- One way to predict the possible effects of future climate change on
geographic ranges is to look back at the changes that have occurred in
temperature regions since the last ice age ended.
Changes in the distributions of species are already evident in many well-studied
groups of terrestrial, marine, and freshwater organisms, consistent with the
signature of a warmer world.
Concept 51.2
, Biomes major life zones characterized by vegetation type in terrestrial biomes
or by the physical environment in aquatic biomes.
Because climate has a strong influence on the distribution of plant species, it is a
major factor in determining the locations of terrestrial biomes. One way to
highlight the importance of climate on the distribution of biomes is to construct a
climograph.
Climograph a plot of the annual mean temperature and precipitation in a
particular region.
The climograph is based on annual averages.
Most terrestrial biomes are names for major physical or climatic features and for
their predominant vegetation. Each biome is also characterized by
microorganisms, fungi, and animals adapted to that particular environment.
Ecotone the area of intergradation, may be wide or narrow.
Vertical layering of vegetation is an import feature of terrestrial biomes. In many
forests, the layers from top to bottom consist of the upper canopy the low-
tree layer, the shrub understory, the ground layer of herbaceous plants, the
forest floor and the root layer.
The species composition of each kind of biome varies from one location to
another.
Biomes are dynamic, and disturbance rather than stability tends to be the rule.
Disturbance an event such as storm, fire, or human activity that changes a
community, removing organisms from it and altering resource availability.
Zie figuur 51.11 voor verschillende “terrestrial biomes”. (p. 1213)
Concept 51.3
Aquatic biomes are characterized primarily by their physical environment. They
also show far less latitudinal variation, with all types found across the globe.
Water evaporated from the oceans provides most of the planet’s rainfall, and
ocean temperatures have a major effect on global climate and wind patterns.
Light is absorbed by the water itself and by photosynthetic organisms, so its
intensity decreases rapidly with depth.
Upper photic zone where there is sufficient light for photosynthesis.
Lower aphotic zone where little lights penetrates.
The photic and aphotic zones together make up the pelagic zone.
Deep in the aphotic zones lies the abyssal zone, the part of the ocean 2000-
6000 m below the surface.
At the bottom of all of these aquatic zones, deep or shallow, is the benthic
zone.
Made up of sand and organic and inorganic sediments, the benthic zone is
occupied by communities of organisms collectively called the benthos.
A major source of food for many benthic species is dead organic matter called
detritus, which “rains” down from the productive surface waters of the photic
zone.
In the ocean and most lakes, a narrow layer of abrupt temperature change called
LDM103
Ecology is a rigorous experimental science that requires a breadth of biological
knowledge. Ecologist observe nature, generate hypotheses, manipulate
environmental variables and observe outcomes.
Concept 51.1
The most significant influence on the distribution organisms on land and in the
ocean is climate the long-term prevailing weather conditions in a given area.
Climate at two scales: - Macroclimate patterns on the global, regional, and
landscape level.
- Microclimate very fine, localized patterns.
Global climate patterns are determined largely by the input of solar energy and
earth’s movement in space.
Climate patterns include seasonal variation and can be modified by other factors
(such as large bodies of water and mountain ranges).
In addition to these global changes day length, solar radiation, and temperature,
the changing angle of the sun over the course of the year affects local
environments.
Ocean currents influence climate along the coasts of continents by heating or
cooling overlying air masses that pass across the land. Because of the high
specific heat of water oceans and large lakes tend to moderate the climate of
nearby land.
Mountains also influence air flow over land warm air approaches a mountain,
the air rises and cools. Cooler, dry air descends, absorbing moisture and
producing a “rain shadow”.
Mountains also affect the amount of sunlight reaching an area and thus the local
temperature and rainfall.
Many features in the environment influence microclimate by casting shade,
altering evaporation form soil, or changing wind patterns. Every environment on
Earth is characterized by a mosaic of small-scale differences in chemical and
physical attributes, such as temperature, light, water, and nutrients. These
abiotic , or nonliving, factors influence the distribution and abundance of
organisms.
Because climate variables affect the geographic ranges of most plants and
animals, any large-scale change in Earth’s climate profoundly affects the
biosphere. as example: the burning of fossil fuels and deforestation are
increasing the concentrations of carbon dioxide and other greenhouse gases in
the atmosphere.
- One way to predict the possible effects of future climate change on
geographic ranges is to look back at the changes that have occurred in
temperature regions since the last ice age ended.
Changes in the distributions of species are already evident in many well-studied
groups of terrestrial, marine, and freshwater organisms, consistent with the
signature of a warmer world.
Concept 51.2
, Biomes major life zones characterized by vegetation type in terrestrial biomes
or by the physical environment in aquatic biomes.
Because climate has a strong influence on the distribution of plant species, it is a
major factor in determining the locations of terrestrial biomes. One way to
highlight the importance of climate on the distribution of biomes is to construct a
climograph.
Climograph a plot of the annual mean temperature and precipitation in a
particular region.
The climograph is based on annual averages.
Most terrestrial biomes are names for major physical or climatic features and for
their predominant vegetation. Each biome is also characterized by
microorganisms, fungi, and animals adapted to that particular environment.
Ecotone the area of intergradation, may be wide or narrow.
Vertical layering of vegetation is an import feature of terrestrial biomes. In many
forests, the layers from top to bottom consist of the upper canopy the low-
tree layer, the shrub understory, the ground layer of herbaceous plants, the
forest floor and the root layer.
The species composition of each kind of biome varies from one location to
another.
Biomes are dynamic, and disturbance rather than stability tends to be the rule.
Disturbance an event such as storm, fire, or human activity that changes a
community, removing organisms from it and altering resource availability.
Zie figuur 51.11 voor verschillende “terrestrial biomes”. (p. 1213)
Concept 51.3
Aquatic biomes are characterized primarily by their physical environment. They
also show far less latitudinal variation, with all types found across the globe.
Water evaporated from the oceans provides most of the planet’s rainfall, and
ocean temperatures have a major effect on global climate and wind patterns.
Light is absorbed by the water itself and by photosynthetic organisms, so its
intensity decreases rapidly with depth.
Upper photic zone where there is sufficient light for photosynthesis.
Lower aphotic zone where little lights penetrates.
The photic and aphotic zones together make up the pelagic zone.
Deep in the aphotic zones lies the abyssal zone, the part of the ocean 2000-
6000 m below the surface.
At the bottom of all of these aquatic zones, deep or shallow, is the benthic
zone.
Made up of sand and organic and inorganic sediments, the benthic zone is
occupied by communities of organisms collectively called the benthos.
A major source of food for many benthic species is dead organic matter called
detritus, which “rains” down from the productive surface waters of the photic
zone.
In the ocean and most lakes, a narrow layer of abrupt temperature change called
