An Introduction to Ecology and the
Biosphere
Types of Ecology
• Organismal ecology – how an
organism’s structure,
physiology and behavior meet
the challenges posed by its
environment
• Population ecology – analyzes
factors that affect population
size and how and why it
changes through time
• Community ecology – examines
how interactions between
species affect community
structure and organization
Types of Ecology
• Ecosystem ecology –
emphasizes energy flow and
chemical cycling between
organisms and the environment
• Landscape ecology – focuses
on the factors controlling
exchanges of energy, materials
and organisms across multiple
ecosystems
• Global ecology – examines how
the regional exchange of energy
and materials influences the
functioning and distribution of
organisms across the biosphere
Evolution and Ecology
• Organisms adapt to their environment over
many generations through natural selection
– This occurs in evolutionary time
– Differential survival and reproduction of
individuals that leads to evolution occurs
in ecological time
• These principals are very much related to
conservation and environmentalism
– Rachel Carson was an important figure
in this movement
Species Distribution
• Many factors are related to distribution patterns of species
– Biotic factors: all of the organisms that are a part of the
individuals environment
– Abiotic factors: all chemical and physical factors, such as
temperature, light, water, nutrients
• It is not uncommon for both types of factors to play a role in
distribution directly or indirectly
Dispersal and Distribution
• Natural range expansions occur when
organisms are able to reach new territory
through their own natural movements
– Limited by potential modes of
transportation
– Ex: a kangaroo can’t swim the pacific
to another location, but a coconut
could float from one island to another
gaining new territory
• Species transplants occur when a species
is accidentally or purposefully transported
to a new territory
– Often called exotic / invasive / alien
species
– Shows the potential range of an
organism and limits of natural dispersal
Species Distribution
• Distribution can be limited
naturally by animal behavior and
selection of a specific habitat
– Ex: European corn borer
larvae can eat a variety of
items, but eggs are laid
primarily on corn because of
an odor given off by the plant
• Distribution can be affected by
biotic factors
– There is a direct relationship
between the eater and the
eaten. They can regulate
each other’s distribution.
Species Distribution
• Distribution can be affected by abiotic
factors
– Temperature – limits on heat as well as
cold
– Water – specific adaptations in plants
and animals help to continue processes
depending on availability
– Salinity – can affect osmotic regulation in
organisms; specific adaptations are
necessary
– Sunlight – amount of light directly affects
what plants are able to grow which
affects distribution of other organisms
– Rocks and Soil – pH, mineral
composition and physical structure can
limit organisms
Climate and Species Distribution
• Climate is largely composed of temperature,
precipitation, sunlight and wind over a long-term
period
– Macroclimate – patterns on global, regional and local
level
– Microclimate – fine patterns such as those
encountered by a community of organisms in a small
area (i.e. under a rock or a log)
Macroclimate
• Global climate patterns are related to several factors
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Latitudinal variation in sunlight intensity
Seasonal variation in sunlight intensity
Global air circulation and precipitation patterns
Global wind patterns
Macroclimate
• Regional, local and seasonal
effects are related to several factors
– Bodies of water help to regulate
temperature variation and can
play a role in precipitation
amounts
• Oceans do this on a larger
scale and have a large effect
on the global climate
– Mountains can affect the
availability of sunlight and can
also create a “rain shadow”,
often giving rise to deserts
Species Distribution and Climate
Change
• As the climate changes, the areas in which species can
live will change
– Distributions will be directly related to limiting factors
related to biotic and abiotic conditions
– Temperature and precipitation availability will be
leading factors
Aquatic Biomes
• Make up most of the Earth
• Broken into freshwater and saltwater (marine) biomes
– Salt concentration generally varies between 3% (marine)
and 0.1% or less (fresh)
– Ocean is largest biome making up 75% of the Earth
• Related to evaporation of water for rainfall, regulation of
temperature, holds photosynthetic organisms
responsible for most of the worlds oxygen and
consumes carbon dioxide
Aquatic Biomes
• Aquatic biomes are organized into zones
– Photic /aphotic – related to light availability
– Benthic zone – bottom
• Abyssal zone found at 2,000-6,000 m below sea level in
the ocean
– Littoral zone – home to rooted and floating aquatic plants
– Limnetic zone – too deep for rooted plants, this area is
home to phytoplankton and cyanobacteria
Aquatic
Biomes
• Many bodies of water will exhibit a thermocline
– This area occurs when there is a temperature difference
between the upper layers of the water and the deeper
waters
• Many lakes also exhibit seasonal turnovers
– Temperature variations cause mixing of the waters
particularly in spring and fall.
• This is caused by density of water rather than actual
temperature, but density of water changes with
temperature
• Remember that water is most dense at 4°C
– As density and temperature become more uniform, water is
also easily mixed by wind
Aquatic Biomes
• There are a wide variety of aquatic biomes
including:
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Lakes
Wetlands
Streams and Rivers
Estuaries
Intertidal zones
Oceanic pelagic zones
Coral Reefs
Marine Benthic Zones
Terrestrial Biomes
• Terrestrial biomes are very much
related to climatic patterns
– Averages are important, but
the pattern of those climatic
factors is more important
• Ex: 2 areas may receive
similar precipitation
through the year, but one
of those regions may have
distinct wet and dry
seasons
• Generally most modified because
of disturbance, such as fire, storm
or human activity
– These effect species
distribution
Terrestrial Biomes
• There are a wide variety of terrestrial biomes
including:
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Tropical forest
Desert
Savanna
Chaparral
Temperate grassland
Northern coniferous forest
Temperate broadleaf forest
Tundra