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