Behavior Biology

Behavior Biology

• Analysis of Behavior

  • Proximate Causation

  • Focus: What behavior is exhibited and what mechanisms drive that behavior.

  • Ultimate Causation

  • Focus: Why the behavior evolved and how it enhances survival.

Ethology

• Definition: The study of the natural history of behavior.

• Main Types:

  • Innate Behavior:

  • Instinctive, genetic; characterized by fixed action patterns.

  • Learned Behavior:

  • Altered behavior resulting from prior experiences.

Innate Behavior

• Components:

  • Key Stimulus: Identified by the organism (e.g., a goose and an egg).

  • Fixed Action Pattern: A motor program that is activated by the key stimulus and executes to completion.

Learned Behavior

• Types:

  • Classical Conditioning: Learning through involuntary associations between stimuli.

    • Example: Pavlov's dogs salivating at the sound of a bell associated with food.

  • Operant Conditioning: Learning through voluntary behaviors influenced by consequences (rewards or punishments).

    • Example: Rats pressing levers for food rewards.

Instincts vs Learning

• Instincts and learning can interact.

  • Example: Male White-crowned Sparrows have an innate ability to learn specific mating songs; they are programmed to learn tunes but require exposure to develop the ability to sing them.

Behavioral Ecology

• Definition: Study of behavioral interactions in populations and communities within an evolutionary context.

  • Example: Sea gull parents removing eggshells to reduce the risk of predation on hatchlings.

  • Findings: Eggshell removal increases offspring survival.

Ecology Basics

• Definition: Study of interactions between organisms and their abiotic/biotic environment.

  • Abiotic Factors: Temperature, sunlight, water, inanimate resources.

  • Biotic Factors: Living elements, such as producers and consumers.

Resources

• Types:

  • Nonrenewable Resources: Finite; e.g., fossil fuels, minerals.

  • Renewable Resources: Naturally replenished; e.g., fresh water, air.

Biogeochemical Cycles

• Definition: Movement of biological and chemical processes within ecosystems.

  • Quote: "When one tugs at a single thing in nature, he finds it attached to the rest of the world." - John Muir.

The Hydrologic Cycle

• Overview: Water is stored in oceans; solar energy causes evaporation. Water vapor condenses, precipitates, and returns to oceans through rivers and lakes.

• Key Processes:

  • Evaporation, Condensation, Precipitation, Infiltration, Evapotranspiration.

The Carbon Cycle

• Process:

  • Photosynthetic organisms fix carbon from CO$_{2}$ into organic molecules (sugars).

  • Sugars enter food webs, are utilized in respiration, and can be released back as CO$_{2}$.

The Nitrogen Cycle

• Process:

  • Nitrogen-fixing bacteria convert N${2}$ into ammonia (NH${3}$), then nitrifying bacteria convert NH${3}$ to nitrites (NO${2}^-$) and nitrates (NO$_{3}^-$) usable by plants.

The Phosphorus Cycle

• Overview: Phosphorus is released from rocks into the soil cycle, taken in by producers and passed through food webs.

Population Ecology

• Definition: Study of factors affecting the change in population size.

• Population Growth:

  • Patterns:

  • Exponential Growth (J Curve)

  • Logistic Growth (S Curve)

Evolutionary Strategies

• Reproductive Strategies:

  • R-Selection: High offspring quantity, lower survival rate.

  • K-Selection: Fewer offspring with better chances of survival.

Community Ecology

• Definition: Study of species interactions within communities.

• Species Richness: Number of species present in an environment.

• Primary Productivity: Energy produced within an ecosystem.

Biodiversity

• Definition: The variety of living organisms.

  • Types:

  • Genetic diversity, species diversity, ecological diversity.

  • Benefits: Increased ecosystem resilience, crucial for ecological stability.

Invasive Species and Fragmentation

• Threats:

  • Invasive species disrupt local biodiversity, often thriving without natural predators. Fragmentation reduces habitat size, impacting species needing larger territories.

Primary Production

• Overview: Amount of energy produced in an ecosystem is foundational to food webs.

Ecological Niche

• Definition: Total utilization of resources by an organism, including habitat, diet, and reproductive conditions.

• Types of Niches:

  • Fundamental Niche: Potential role if no competition.

  • Realized Niche: Actual conditions of existence based on competition and interactions.

Species Interactions

• Types:

  • Neutralism: Both species unaffected.

  • Amensalism: One is neutral, the other is harmed.

  • Commensalism: One benefits, the other is neither helped nor harmed.

  • Competition: Both harmed by resource scarcity.

  • Mutualism: Both benefit.

  • Predation/Parasitism: One benefits at another's expense.