Ecological Concepts
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
Level(s) at which organism obtain energy
Autotrophs
Organisms that obtain energy directly from physical environment
Called "producers"; most are photosynthetic, but in some env't chemosynthetic autotrophic organisms exist
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
Organisms that obtain energy from the dead and decaying biological environment; e.g. fungi & bacteria
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
Elements cycle between gaseous, liquid, and solid forms in nature
e.g. nitrogen, water, and carbon cycles
Chemistry of molecules effects 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: input of carbon into atmosphere
Drought: removal of ground water and/or reduced precipitation
Eutrophication: input of nitrogen into watersheds
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
Mutualism
Two organisms are enhanced by interactions (e.g. mycorrhizal fungus, insect pollination)
Parasitism
One organism is enhanced; the other is hindered by interaction (e.g. water molds, mucoromycetes)
Commensalism
One organism is enhanced; the other is neither helped nor hindered by interaction (e.g. epiphytic orchid)
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
Science that studies and implements succession principles
Restoration of natural communities
Additional Resources
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)
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; peer-reviewed Chen et al. 2023)
Agro-sequestration for solving global greenhouse gas emissions (ScienceBlog 12Apr2023; Peer-reviewed: Yablonovitch & Deckman 2023)
Old Growth Forests (YouTube 2020)
Temperature drives biodiversity (Peters et al. 2016)