Embedded Files
Ecology
Ecology
Study of the interactions between the biotic and abiotic environmentStudy of ecosystems (all organisms in a particular area and physical environment)
Population: all individuals of a species in an area
Community: all populations in an area
Trophic Levels
Trophic Levels
Level(s) at which organisms obtain energy
Autotrophs
Autotrophs
Organisms that obtain energy directly from the physical environment
Called "producers"; most are photosynthetic, but in some environments chemosynthetic autotrophic organisms exist
Heterotrophs
Heterotrophs
Organisms that obtain energy from the biological environment
Primary consumers: Feed directly on autotrophs, e.g., herbivores
Secondary consumers: Feed on primary consumers, e.g., carnivores
Decomposers
Decomposers
Organisms that obtain energy from the dead and decaying biological environment, e.g., fungi & bacteria
Saprotrophs: Organisms that feed on dead and decaying organisms
Energy Pyramids
Energy Pyramids
graphical representation of energy flow through an ecological system
Producers (plants / algae) usually have 10x more biomass than primary consumers
90% loss of energy from tier to tier
Nutrient Cycling
Nutrient Cycling
Elements cycle between gaseous, liquid, and solid forms in nature
e.g., nitrogen, water, and carbon cycles
Chemistry of molecules affects cycling; water facilitates the cycling of other molecules
Photosynthetic organisms play a large role in trapping and cycling nutrients
Many of our environmental issues can be explained by nutrient cycling that is out of balance
Global warming
Global warming
Input of greenhouse gases into the atmosphere. This could be methane, but frequently it is carbon dioxide. Fossil fuels, comprised of carbon captured by plants millions of years ago, are released into the environment.
Drought
Drought
The removal of groundwater and/or reduced precipitation due to overconsumption and/or climate change.
Eutrophication
Eutrophication
Input of solid nitrogen into watersheds causes blooms of algae. As they die and decompose, they consume oxygen in the water, causing anoxia.
Competition
Competition
An interaction between organisms in which both the species are harmed.
Competition occurs when organisms require same resources (e.g. light, soil, space)
Competition drives natural selection at the population and species level
In plants, rapid vegetative growth and/or efficient sexual reproduction provide an “edge”
Some plants create chemical substances that deter competitor’s growth (allelopathy)
Competition will favor specialization to an environment, which may create adaptations
Specialization might make a species less fit in a changing environment
Other Symbioses
Other Symbioses
Mutualism
Mutualism
Two organisms are enhanced by interactions (e.g. mycorrhizal fungus, insect pollination)
Parasitism
Parasitism
One organism is enhanced; the other is hindered by interaction (e.g. water molds, mucoromycetes)
Commensalism
Commensalism
One organism is enhanced; the other is neither helped nor hindered by interaction (e.g. epiphytic orchid)
Succession
Succession
Change in a community over time
Ecosystem change:
e.g. Pond -> Marsh -> Swamp -> Field -> Forest
Growth form change: The overall type or forms of plants changes over time
e.g. Rocky outcrop -> Lichens -> Grasses --> Shrubs --> Trees
Environmental disturbance restarts succession
Volcanic explosion, Floods/erosion, Fires, etc.
Restoration ecology
Restoration ecology
Science that studies and implements succession principles
Restoration of natural communities
Additional Resources
Additional Resources
Forests recovering from acid rain mine rocks for nutrients (Phys.org 23Oct2025)
└Forest recovery after deforestation is fueled by mineral weathering at the expense of ecosystem buffering capacity (Bernhardt et al., 2025)
Beavers return to the forest landscape, reviving its natural environment (5Sep2025)
└Kivinen et al. (2025) Immediate facilitation and engineering legacy of beavers: 54 years of patch dynamics in a boreal landscape
Peatlands across the Arctic are expanding as the climate warms, research shows (Phys.org 19Jun2025)
└Crichton et al. (2025) Satellite data indicates recent Arctic peatland expansion with warming
Diatom surprise could rewrite the global carbon cycle (Phys.org 17Jul2024)
└Kumar et al. (2024) Mixotrophic growth of a ubiquitous marine diatom
Large herbivores such as elephants, bison and moose shown to contribute to tree diversity (3Nov2023 Phys.org)
└Wang et al. (2025) Tree cover and its heterogeneity in natural ecosystems is linked to large herbivore biomass globally
How to save plants from climate change. The answers may be the language of their tissues and physiology (Phys.org 26Sep2023)
└Medeiros et al. (2023) Predicting plant species climate niches on the basis of mechanistic traits
Iron dust could reverse the course of climate change (NY Times 14Sep2023)
America's biggest source of water pollution is farms (Vox 31Aug2023)
Tree Diversity Increases Storage of Carbon and Nitrogen in Forest Soils, Mitigating Climate Change (ScienceBlog 1May 2023)
└Chen et al. (2023) Tree diversity increases decadal forest soil carbon and nitrogen accrual
Agro-sequestration for solving global greenhouse gas emissions (ScienceBlog 12Apr2023)
└Yablonovitch & Deckman (2023) Scalable, economical, and stable sequestration of agricultural fixed carbon
Old Growth Forests (YouTube 2020)
Temperature drives biodiversity (Peters et al., 2016)
Google Sites
Report abuse