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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 experiments2. some research done in laboratories3. 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
• 1. photosynthetic organisms use sunlight (abiotic factor) and produce oxygen as a bi-product which is used by organisms for cellular respiration
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
Organism
Population
Community
Biosphere
Ecosystem
Abiotic factors
• temperature1. 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 metabolism3. even endotherms function best within a temperature range
Abiotic factors
• water 1. essential for life2. 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 timemost important components–Precipitation–Temperature–Wind
Convection
Heat transfer in a fluid (liquid or gas)Heat risesThe current formed is a
Convection Cell
Desert Latitude
30 degrees N or SCool 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 BiomesThe most common biomes are:
• 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
TundraFound 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