The Scope of Ecology
Chapter 34
What is ecology?
Ecology- the scientific study of
interactions between organisms
and their environments,
focusing on energy transfer
• It is a science of relationships.
Oikos- greek for “house”
Ecology is primarily a
descriptive science but is
becoming more experimental
1. very difficult to control experiments
2. some research done in laboratories
3. most done in the field
What do you mean by environment?
The environment is made up of two
factors:
Biotic factors- all living organisms
inhabiting the Earth
Abiotic factors- nonliving parts of
the environment (i.e. temperature,
soil, light, moisture, air currents)
Interaction
• interaction includes how the
environment affects the organism and
how the organism can alter the
environment
Interaction
photosynthetic organisms use
sunlight (abiotic factor) and produce
oxygen as a bi-product which is used
by organisms for cellular respiration
• 1.
Interaction
• 2.
shading of the forest floor by
trees can make the environment less
suitable for their offspring to grow,
yet more suitable for other organisms
Levels of Ecology
• ecological research ranges from
studying adaptations of organisms to
the dynamics of ecosystems
• Organism- any unicellular or
multicellular form exhibiting all of
the characteristics of life, an
individual.
• The lowest level of organization
• 1. organismal ecology – study of the
way organisms meet the challenges of
abiotic environmental factors
• e.g., reptiles retreat to shaded areas
to maintain body temperature
• Population-a group of organisms of
one species living in the same place
at the same time that interbreed
and compete with each other for
resources (ex. food, mates,
shelter)
2.
population ecology – study of
populations and interaction with
environment
e.g., what environmental factors affect
population size and composition?
• Community- several interacting
populations that inhabit a common
environment and are interdependent.
• 3.
community ecology – study
of all organisms that inhabit an
area
• e.g., study of predator – prey
relationships, competition, disease
• 4.
ecosystem ecology – study of all
abiotic factors as well as all organisms in
an area
• e.g., study of energy flow and chemical
cycling among the biotic and abiotic
components
• Biosphere- life supporting portions
of Earth composed of air, land,
fresh water, and salt water.
• The highest level of organization
• 5. Biosphere ecology – studying the
global system of living things
• e.g. humans effect on the ozone layer
or climate change
Biosphere
Ecosystem
Community
Population
Organism
Abiotic factors
• temperature
1.
most organisms are NOT able to
regulate their body temperature; i.e.,
they’re ectothermic as apposed to
endothermic
2.
temperature has a tremendous
affect on metabolism
3.
even endotherms function best
within a temperature range
Abiotic factors
• water
1. essential for life
2. poses osmotic challenges for
organisms
Abiotic factors
• wind amplifies the effects of
temperature by increasing heat loss
and evaporation
Abiotic factors
Climate
Weather over a long period of time
most important components
– Precipitation
– Temperature
– Wind
Convection
Heat transfer in a fluid (liquid or gas)
Heat rises
The current formed is a
Convection Cell
Desert Latitude
30 degrees N or S
Cool dry falling air limits precipitation
Rain-Shadow Effect
Rain Shadow Effect
Air flowing over mountain ranges rises and
cools, losing moisture
Climate is much dryer on the backside of
the mountain range
Coriolis Effect
Coriolis effect is the apparent
curvature of global winds, ocean
currents, and everything else that
moves freely across the Earth's
surface.
Northern Hemisphere- everything
turns right causing counterclockwise
rotation of weather systems
Polar Easterlies
Westerlies
Northeast
Tradewinds
Seasons
Seasons are caused by the Earth’s tilt on
its axis
Terrestrial Biomes
Terrestrial Biomes
Biome- geographic areas that have
similar climates and ecosystems
Terrestrial Biomes
The most common biomes are:
•
•
•
•
•
•
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Tundra
Taiga
Temperate Deciduous Forest
Tropical Rain Forest
Grassland
Savanna
Desert
Terrestrial biomes
Tundra is located in areas where
temperatures minimize plant growth
but not covered completely with ice
Tundra
Found in parts of Canada, Alaska, and Siberia
Tundra –
“The Cold Desert”
• Found at latitudes
around the North Pole
• Less than 25 cm
precipitation yearly
• Very cold year round
(-40ºC in winter)
• Cold, dry, treeless
region
Tundra –
“The Land of the
Midnight Sun”
• Winter lasts 6 to 9
months with no
daylight
• Summer is short and
cold with 24 hours of
sunlight a day
Tundra-
• Soil is poor
• Permafrost
–Layer of
permanently
frozen soil
Plants of the Tundra
Tundra plants are resistant to drought
and cold
Plants of the Tundra
• Reindeer moss – It’s a lichen!
Plants of the Tundra
• Lichens
Plants of the Tundra
• Lichen
Plants of the Tundra
• True Mosses
Plants of the Tundra
• Small shrubs and flowers
Plants of the Tundra
• Small shrubs and flowers
Plants of the Tundra
• Small shrubs and flowers
Plants of the Tundra
• Grasses
Animals of the Tundra
Many animals of the tundra migrate
there during the short summer
Animals of the Tundra
• Biting insects
Mosquito
Blackfly
Animals of the Tundra
• Snowy owl
Animals of the Tundra
• Arctic hare
Animals of the Tundra
• Caribou – “Reindeer”
Animals of the Tundra
• Musk oxen
Animals of the Tundra
• Lemmings
Animals of the Tundra
• Lemmings