Ecology: Cycles, Systems, and Energy Flow

• Heat is lost at each level of the food chain, representing energy loss.
• The 10% rule dictates that only 10% of energy is passed on to each subsequent level of the food chain.
• Systems are networks of interdependent components and processes where materials and energy flow.
• A positive feedback loop intensifies changes in a system, leading to more of the same change.
• A negative feedback loop suppresses changes in a system, helping to maintain stability.

Hydrologic Cycle

• Solar energy is absorbed by water in oceans and on land
• Water evaporates and is distributed globally as water vapor.
• Water condenses over land, supporting terrestrial ecosystems.

Carbon Cycle

• Atmospheric carbon sources include respiration, decomposition, and combustion.

• Atmospheric carbon sinks include photosynthesis and ocean uptake.

• Carbon dioxide and water combine to form carbonic acid, which can increase ocean acidity.

• Adaptation is the process of acquiring traits that allow species to survive in their environments, driven by natural selection.

• Mutation is the basis of all adaptation.

• Allopatric speciation is the development of new species due to geographic isolation.

• Sympatric speciation occurs when new species develop while organisms continue to live in the same place but become isolated by other means.

• Competitive exclusion states that no two species can occupy the same ecological niche simultaneously; the more efficient species will exclude the other.

• Resource partitioning occurs when species with similar niches divide up a resource or segregate it in some way.

• A mutualistic relationship is when two species benefit from each other.

• Commensalism is when one species benefits while the other is not affected.

• Parasitism is a form of predation where a parasite depends on its host.

• Ecosystems are dynamic and always changing, which leads to ecological succession.

• Ecological succession is the process of change in species composition due to changes in their environment.

• Primary succession is the establishment and development of an ecosystem where one did not exist previously.

• Pioneer species are the first to colonize, followed by intermediate species, leading to a climax community.

• Secondary succession is the reestablishment of an ecosystem after a disturbance, building upon the remaining biological community.

• Disturbances are any forces that disrupt established patterns of species diversity and abundance, community structure, or community properties.

• N represents the total number of all members in a single species living in a specific area at once.

• r represents the rate of growth, indicating the number of animals that can be produced per unit of time.

• t represents the unit of time.

• Carrying capacity is the population size of a species that can be supported in a specific area without depleting available resources.

• Overshoot occurs when a population exceeds the carrying capacity of the environment.

• A population crash is a rapid dieback of a species due to limited resources.

• Density-dependent factors, such as disease and predation, intensify as population size increases.

• Density-independent factors, such as drought, fire, and other habitat destruction, affect populations regardless of size.

• Until the invention of agriculture 10,000 years ago, the human population was a few million.

• Populations remained relatively steady due to disease, famine, and war.

• After 1600, the population began to increase due to agricultural development, better sources of power, healthcare, and hygiene.

• The crude death rate is the number of deaths in a year per 1,000 people.

• Poor countries have a crude death rate of about 20, while wealthier countries have a rate of about 10.

• Fertility rates indicate the number of children born to the average woman during her lifetime.

• High-income countries have fertility rates around 1, while lower-income countries have rates around 4 or 5.

• The crude birth rate is the number of births in a year per 1,000 people.

Explore energy loss in food chains and the 10% rule. Learn about systems, positive and negative feedback loops, and the hydrologic and carbon cycles. Understand carbon sources/sinks and adaptations.