Ecology and Ecosystems

Ecology O2 Nutrients CO2 Ecology is the study of relationships between living things and between living things and their environment. Relationships involve interactions with the physical world as well as interrelationships with other species and individuals of the same species.

Biological Complexity Living organisms can be studied at different levels of complexity. From least to most complex, these levels are (in an ecological context): Individual Population Community Ecosystem Biome Biosphere Biosphere Biome Ecosystem Community Population Individual

The Biosphere The biosphere is the region within which all living things are found on Earth. It is the narrow belt around the Earth extending from the bottom of the oceans to the upper atmosphere.

Biomes The biosphere encompasses all living things on Earth. It comprises a number of aquatic and terrestrial biomes. Biomes are the largest geographically based biotic communities that can be conveniently recognized. Biomes within the same category have specific, characteristic features.

Terrestrial Biomes Terrestrial biomes are recognized for all the major climatic regions of the world and are classified on the basis of their predominant vegetation type. The same biome may occur in widely separated regions.

Aquatic Biomes

What is an ecosystem? An ecosystem is a system of living things that interact with each other and with the physical world. A Biome is a collection of related ecosystems.

Habitat The place in which an organism lives provides the kinds of food and shelter, the temperature, and the amount of moisture the organism needs to survive The environment is a “global” set of conditions, both biotic and abiotic that affect an organism in it’s lifetime. An environment may contain multiple habitats

Communities A community is a naturally occurring group of organisms living together as an ecological entity; the biological part of the ecosystem. A nudibranch snail feeding on rock encrusting organisms

Populations All the organisms in an ecosystem that belong to the same species

Individual: species Organisms that can successfully interbreed to produce sexually viable offspring

Abiotic factors Abiotic = non-living Temperature Humidity Wind & air currents Water, water pressure & currents Light pH Salinity Nutrients Topography Background Shelter

1. Temperature Range Extremes Fluctuation Duration Thermoclines

Humidity Cooling ability Resistance to dessication Aestivation Resistance to disease

Wind and Air currents Root, stem and leaf structure Flying ability Dispersal mechanisms

Water, water pressure and currents Retention (eg clay soils) Current strength Wave action Depth control/pressure/resistance Oxygenation Food/nutrient availibility

Light Intensity Duration Exposure Seasonality (circadian rhythms)

pH Range Variance Acidity/alkalinity

Salinity Concentration Thresholds Variance Water table/salt levels

Nutrients Levels Availibility (e.g. Nitrogen) Variance

Topography Variance Altitude

Background Fluctuation Consistency Textural patterns (cryptic species)

Shelter Availability Type Conditions within