Intro to Ecology

Ch Intro to Ecology Ecology is the study of the interactions between organisms and the living and nonliving components of their environment. Key Ecology Concepts: Interdependence Levels of Organization Energy Transfer Biogeochemical Cycles Properties of Populations Species Interactions Succession Terrestrial & Aquatic Ecosystems Human Impact

Levels of Organization

Ch Ecology of Organisms Components of an Ecosystem: Habitat- the place where an organism lives. Biotic Factors- living parts of the environment. Abiotic Factors- nonliving parts of the environment.

Organisms in a changing environment: How organisms survive within a limited range of environmental conditions (abiotic factors): Tolerance Curve Model Organisms can adjust their tolerance to the factors by acclimating.

Control of Internal Conditions: Environments fluctuate in their various abiotic factors. How do organisms respond? Conformers- do not regulate their internal conditions; depend on their external environment. Example: reptiles Regulators- use energy to control their internal conditions. Example: mammals

Escape from Unsuitable Conditions: 1. Organisms only being active during certain parts of the day. Example: Desert animals 2. Dormancy- long term strategy where the organism goes in to a state of inactivity. Example: bears hibernating 3. Migration- organism moving to a more favorable habitat.

Niche Niche describes the role an organism has within its environment. Examples: conditions the organism can live in; resources it uses; methods it uses to obtain resources; # of offspring it produces; reproduction time; all other interactions with the environment. Generalists- species with a broad niche. Example: opossum Specialist- species that have narrow niches. Example: koala, panda

Chapter 18.3 Energy Transfer Producers- organisms that can produce their own food; also called autotrophs. Examples: plants, bacteria, protists. Bacteria use the process of chemosynthesis; use energy in inorganic molecules to produce carbohydrates.

Consumers- heterotrophs that must obtain energy by consuming other organisms. 1. Herbivores 2. Carnivores 3. Omnivores 4. Detritivores Decomposers

Energy Flow Trophic Levels represent position of an organism within food chains and food webs. As steps within a food chain/web increase, only 10% of the available energy is passed to the next organism. Because of the rapid decrease in available energy, trophic levels are limited.

Ch Ecosystem Recycling Biogeochemical Cycles- how water, carbon, nitrogen, phosphorus, calcium, and sulfur pass between living organisms and nonliving structures. Organisms need these substances to grow and survive, but the substances need to be in a certain form to be useful. The cycles of these substances convert them in to usable forms.

Water Cycle -evaporation -transpiration -condensation -precipitation -percolation

Carbon Cycle -photosynthesis -cell respiration -decomposition -combustion

Nitrogen Cycle Nitrogen Fixation: converting nitrogen gas using bacteria to a usable form (nitrates). Recycling Nitrogen from Decomposition: 1. Ammonification (NH 3 to NH 4 + ) 2. Nitrification (NH 4 + to nitrates) Denitrification (nitrates to N 2 )

Phosphorus Cycle