General Biology: Final Exam Study Notes (Fungi, Animal Diversity, Ecology, and Ecosystems)

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Lecture 15: Fungi

Fungal Phylogeny and Classification

Fungi are a diverse kingdom of eukaryotic organisms that play essential roles in ecosystems as decomposers, mutualists, and pathogens. Understanding their placement in the tree of life and their shared characteristics is fundamental to biology.

Fungal Phylogeny: Fungi are more closely related to animals than to plants, sharing a common ancestor with opisthokonts.
Synapomorphies: Key shared traits include chitin in cell walls, absorptive heterotrophy, and the production of spores.
Fungal Morphology: Fungi exhibit structures such as mycorrhizae (mutualistic associations with plant roots), saprobes (decomposers), and parasites.
Generalized Fungal Life Cycle: Most fungi have a life cycle that includes haploid and diploid stages, with sexual and asexual reproduction via spores.
Fungal Movement: Fungi do not move actively; instead, their spores are dispersed by wind, water, or animals.

Example: Rhizopus (bread mold) demonstrates both sexual and asexual spore production.

Lectures 16-17: Animal Diversity

Animal Phylogeny and Body Plans

Animals are multicellular, eukaryotic organisms with diverse body plans and evolutionary histories. Their classification is based on shared traits and developmental patterns.

Animal Synapomorphies: Multicellularity, heterotrophy, and specialized tissues unite all animals.
Current Animal Phylogeny: Animals are classified into major clades such as Porifera, Cnidaria, Bilateria, etc.
Body Plans: Animals differ in symmetry (radial vs. bilateral), number of tissue layers (diploblastic vs. triploblastic), and presence of a coelom.
Cambrian Explosion: A major evolutionary event (~541 million years ago) that led to rapid diversification of animal body plans.
Vertebrate Evolution: Key adaptations include jaws, limbs, and amniotic eggs, allowing colonization of diverse habitats.
Chordate Clades: Major groups include Cephalochordata, Urochordata, and Vertebrata.

Example: The transition from aquatic to terrestrial vertebrates required adaptations such as lungs and limbs.

Lecture 18-19: Behavioral Ecology

Animal Behavior and Learning

Behavioral ecology examines how animal behavior is shaped by ecological and evolutionary pressures. It includes the study of learning, mating systems, and foraging strategies.

Tinbergen's Four Questions: Proximate (mechanism, development) and ultimate (function, evolution) explanations for behavior.
Innate vs. Learned Behaviors: Innate behaviors are genetically programmed; learned behaviors are acquired through experience.
Types of Learning: Includes habituation, imprinting, classical conditioning, and operant conditioning.
Mating Systems: Monogamy, polygyny, and polyandry differ in parental investment and sexual selection.
Sexual Selection: Traits that increase reproductive success, such as elaborate displays or competition.
Foraging Models: Optimal foraging theory predicts how animals maximize energy intake per unit time.

Example: Birds may learn to avoid toxic prey through operant conditioning.

Lecture 20: Intro to Ecology

Ecological Organization and Patterns

Ecology is the study of interactions among organisms and their environment, organized at multiple levels from individuals to ecosystems.

Levels of Organization: Individual, population, community, ecosystem, biome, biosphere.
Ecological Patterns: Distribution and abundance of organisms, influenced by biotic and abiotic factors.
Ecological Processes: Includes energy flow, nutrient cycling, and succession.
Spatial and Temporal Scales: Ecology examines processes at local, regional, and global scales.
Climatic Factors: Temperature, precipitation, and seasonality affect ecosystem structure.
Biomes: Large ecological zones defined by climate and vegetation (e.g., tundra, rainforest).
Demography: Study of population structure and dynamics.

Example: The rain shadow effect creates dry areas on the leeward side of mountains.

Lecture 21-22: Population Ecology

Population Dynamics and Life History

Population ecology focuses on the factors that affect population size, growth, and structure over time.

Population vs. Species: A population is a group of individuals of the same species in a given area.
Population Growth Models: Exponential () and logistic () growth describe changes in population size.
Life Tables and Survivorship Curves: Tools to study age-specific mortality and survival.
r- and K-selection: r-selected species produce many offspring with little investment; K-selected species produce fewer offspring with more investment.
Density-Dependent Regulation: Population growth is limited by factors such as competition, predation, and disease.
Metapopulations: Groups of populations connected by migration.

Example: Human populations often show a Type I survivorship curve (high survival until old age).

Lecture 23-24: Community Ecology

Species Interactions and Community Structure

Community ecology studies the interactions among species and how these shape community composition and function.

Species Interactions: Includes competition, predation, herbivory, parasitism, mutualism, commensalism.
Fundamental vs. Realized Niche: The fundamental niche is the full range of conditions a species can tolerate; the realized niche is where it actually exists due to interactions.
Ecological Succession: The process by which community composition changes over time (primary vs. secondary succession).
Food Webs: Complex networks of feeding relationships.
Species Richness and Diversity: Influenced by disturbance, area, isolation, and time since disturbance.
Intermediate Disturbance Hypothesis: Predicts highest diversity at intermediate levels of disturbance.

Interaction Type	Effect on Species 1	Effect on Species 2
Competition	-	-
Predation	+	-
Mutualism	+	+
Commensalism	+	0
Parasitism	+	-

Example: Lichens are a mutualistic association between fungi and algae.

Lecture 25-27: Ecosystems Ecology & Biodiversity

Cycles of Matter, Energy Flow, and Biodiversity

Ecosystem ecology examines the flow of energy and cycling of matter through living and nonliving components. Biodiversity is crucial for ecosystem stability and resilience.

Cycles of Matter: Includes the water, carbon, nitrogen, and phosphorus cycles.
Net Primary Productivity (NPP): The rate at which plants convert solar energy into biomass ( where GPP is gross primary productivity and R is respiration).
Biogeochemical Cycles: Movement of elements through reservoirs such as atmosphere, soil, and water.
Biodiversity: The variety of life at genetic, species, and ecosystem levels; important for ecosystem services.
Major Threats to Biodiversity: Habitat loss, invasive species, overexploitation, pollution, and climate change.
Mitigation Strategies: Conservation, restoration, sustainable resource use, and policy interventions.

Biogeochemical Cycle	Main Reservoir	Key Processes
Water	Oceans	Evaporation, precipitation, runoff
Carbon	Atmosphere	Photosynthesis, respiration, combustion
Nitrogen	Atmosphere	Fixation, nitrification, denitrification
Phosphorus	Rocks/soil	Weathering, uptake, sedimentation

Example: Deforestation reduces NPP and disrupts the carbon cycle, contributing to climate change.

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