Ecology and Cellular Metabolism

Fermentation vs. Respiration

• Fermentation is the chemical breakdown of organic substrates by microorganisms, producing heat and effervescence. Respiration is a set of chemical reactions for complete food oxidation, producing energy.
• Fermentation occurs without oxygen, while respiration requires oxygen.
• Fermentation does not produce water as a byproduct, whereas respiration does.
• Fermentation happens in the cytoplasm. Respiration takes place in the mitochondria and cytoplasm.
• Fermentation synthesizes 2 ATP, while respiration produces 36 ATP molecules.
• Types of fermentation include ethanol and lactic acid fermentation. Respiration includes aerobic and anaerobic forms.
• The final electron acceptor in fermentation is an organic molecule; in respiration, it's primarily oxygen.
• Fermentation is common in microorganisms; respiration occurs in higher organisms.

Food Chains and Food Webs

• Food chains and food webs illustrate energy flow and organism interactions in ecosystems.
• Food chains show a single energy pathway between organisms.
• Food webs show the complex interconnectedness of multiple food chains.
• Producers (e.g., plants) form the base (first trophic level).
• Herbivores/primary consumers eat producers.
• Carnivores/omnivores (secondary, tertiary, or quaternary consumers) eat other consumers.
• Energy flows from producers to higher trophic levels in a food web or chain.
• About 10% of energy is transferred between trophic levels; the rest is lost as heat or used for metabolism.

Energy Pyramids

• Energy pyramids show the energy transfer in an ecosystem based on trophic levels.
• Producers receive 100% of the solar energy.
• Primary consumers receive 10% of the energy from producers.
• Secondary consumers receive 1% of the original solar energy.
• Tertiary consumers receive 0.1% of the initial solar energy.
• Energy loss occurs at each level.

The Sun as an Energy Source

• The sun is the Earth's primary energy source.
• Photosynthetic producers convert light energy into chemical energy (glucose).
• Consumers obtain energy by consuming producers.
• The sun's immense heat and pressure drive nuclear fusion, releasing energy.

Food Chains and Trophic Levels

• Food chains are the natural energy flow from one organism to another through eating or being eaten.
• Producers (autotrophs) are at the base, making their own food from sunlight.
• Consumers (heterotrophs) eat plants or animals to gain energy.
• Herbivores eat plants.
• Carnivores eat animals.
• Omnivores eat both plants and animals.
• Decomposers break down dead matter; detritus feeders (worms) and scavengers (buzzards) are types.
• Only 10% of energy is passed between levels.

Biotic Potential and Carrying Capacity

• Biotic potential is the maximum reproductive rate under ideal conditions.
• Carrying capacity is the maximum population size an environment can sustain.
• Environmental resistance limits population growth due to factors like disease, predators, and competition.
• Populations exceeding carrying capacity face resource scarcity.

Symbiosis

• Symbiosis describes relationships between different organisms, where at least one benefits.
• Mutualism: Both organisms benefit.
• Commensalism: One benefits, the other is unaffected.
• Parasitism: One benefits, the other is harmed.
• Ectosymbiosis: Organisms live on another organism.
• Endosymbiosis: Smaller organisms live inside another.

Predation and Coevolution

• Predation is when one organism hunts and eats another.
• Predation is a strong selection pressure for prey.
• Coevolution occurs when species evolve in response to each other.
• Adaptations to predation include camouflage, chemical defenses, and mimicry.

Human Impact on Biodiversity

• Human activities (habitat alteration, over-harvesting, pollution, fossil fuel use) are significant threats to biodiversity.
• Greenhouse gas emissions accelerate climate change, driving species extinction.
• Deforestation contributes to global warming and habitat loss.

Introduced and Invasive Species

• Introduced species live outside their native ranges due to human activity.
• Invasive species disrupt ecological balance due to unchecked growth and local extinctions.
• Lack of natural controls in new environments can drive invasion.

Extinction

• Extinction is the complete disappearance of a species.
• Mass extinctions are sudden and drastic; background extinctions happen more gradually.
• Fossil records offer insights into extinction events.
• Human activities cause ongoing biodiversity loss.

Characteristics of Life

• Reproducing, inheriting traits, cellular organization, growth/development, responding to stimuli, adapting (evolution), maintaining homeostasis, and metabolism are the eight characteristics required to be considered a living thing.

Biological Organization

• Organisms are organized into levels of increasing complexity starting from the atom to the biosphere.
• Atoms --> Molecules --> Macromolecules --> Organelles --> Cells --> Tissues --> Organs --> Organ Systems --> Organisms --> Populations --> Communities --> Ecosystems --> Biosphere.
• Cellular differentiation allows for specialized structures and functions.

Cell Theory

• Cell theory includes three core concepts:
• All living things are composed of cells.
• Cells are the basic unit of life.
• All cells arise from pre-existing cells.
• Cells cannot spontaneously generate.
• Modern cell theory includes the concepts of genetic information transfer, similarities between species' cells, and energy flow within cells.

Explore the fundamentals of cellular metabolism, differentiating between fermentation and respiration. Investigate trophic levels, energy transfer, and the roles of consumers and decomposers within ecosystems. Includes Saccharomyces cerevisiae's metabolic preferences.