General Biology II: Final Exam Study Guide – Fungi, Animal Diversity, Ecology, and Ecosystems

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Lecture 15: Fungi

Fungal Phylogeny and Characteristics

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

Phylogenetic Placement: Fungi are more closely related to animals than to plants, sharing a common ancestor with animals in the Opisthokonta clade.
Synapomorphies: Key shared traits include chitin in cell walls, absorptive heterotrophy, and the production of spores.
Fungal Morphology: Fungi exhibit structures such as hyphae (filamentous cells), mycelium (networks of hyphae), and specialized forms like mycorrhizae (symbiotic associations with plant roots) and haustoria (parasitic structures).
Generalized Fungal Life Cycle: Most fungi have a life cycle that includes both sexual and asexual reproduction, often involving haploid, dikaryotic, and diploid stages.
Fungal Movement: Fungi do not move via flagella (except chytrids); instead, they grow by extending hyphae.
Example: Rhizopus (bread mold) demonstrates a typical zygomycete life cycle with both sexual and asexual spores.

Lectures 16-17: Animal Diversity

Animal Synapomorphies and Body Plans

Animals are multicellular, heterotrophic organisms with unique developmental and structural features. Their diversity is reflected in their body plans and evolutionary history.

Shared Traits: Animals share features such as multicellularity, lack of cell walls, nervous and muscle tissue, and development from a blastula.
Animal Body Plans: Body plans are defined by symmetry (radial vs. bilateral), tissue layers (diploblastic vs. triploblastic), and the presence of a coelom (body cavity).
Major Animal Clades: Major groups include sponges, cnidarians, protostomes (e.g., arthropods, mollusks), and deuterostomes (e.g., chordates, echinoderms).
Cambrian Explosion: A period (~541 million years ago) marked by rapid diversification of animal body plans.
Vertebrate Evolution: Key adaptations include the development of jaws, limbs, and amniotic eggs.
Chordate Features: Notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail.
Example: Comparison of Arthropoda (jointed appendages, exoskeleton) and Chordata (notochord, dorsal nerve cord).

Lectures 18-19: Behavioral Ecology

Animal Behavior and Evolutionary Explanations

Behavioral ecology examines how animal behavior is shaped by ecological and evolutionary pressures, focusing on survival and reproductive success.

Tinbergen's Four Questions: Causation (mechanism), development (ontogeny), function (adaptive value), and evolution (phylogeny).
Proximate vs. Ultimate Causes: Proximate causes explain how behaviors occur; ultimate causes explain why behaviors evolved.
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 pressures.
Sexual Selection: Selection for traits that increase mating success, often leading to sexual dimorphism.
Example: Bird song learning as a model for both innate and learned components of behavior.

Lecture 20: Introduction to Ecology

Levels of Organization and Ecological Patterns

Ecology studies the interactions between organisms and their environment, organized into hierarchical levels and patterns.

Levels of Organization: Individual, population, community, ecosystem, biome, and biosphere.
Ecological Patterns: Distribution and abundance of organisms, spatial and temporal variation.
Ecological Processes: Include energy flow, nutrient cycling, and population dynamics.
Scales: Local (microclimate), regional, and global (climate systems).
Climatic and Abiotic Factors: Temperature, precipitation, sunlight, and soil influence ecosystem structure.
Biomes: Large ecological zones defined by climate and dominant vegetation (e.g., tundra, rainforest).
Example: Rain shadow effect creates dry areas on the leeward side of mountains.

Lectures 21-22: Population Ecology

Population Dynamics and Growth Models

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 growth () and logistic growth (), where is carrying capacity.
Life Tables and Survivorship Curves: Tools to study age-specific survival and reproduction.
r- and K-selection: r-selected species produce many offspring with low survival; K-selected species produce fewer offspring with higher survival.
Density-Dependent and Density-Independent Factors: Density-dependent factors (e.g., competition, disease) intensify as population increases; density-independent factors (e.g., weather) affect populations regardless of size.
Demography: The statistical study of populations, including birth rates, death rates, and age structure.
Example: Human population growth has shifted from exponential to logistic in some regions due to resource limitations.

Lectures 23-24: Community Ecology

Species Interactions and Community Structure

Community ecology examines how species interact and how these interactions shape community composition and dynamics.

Species Interactions: Competition, predation, herbivory, parasitism, mutualism, commensalism, and amensalism.
Fundamental vs. Realized Niche: The fundamental niche is the full range of conditions a species can occupy; the realized niche is where it actually exists due to biotic interactions.
Resource Partitioning: Species divide resources to reduce competition.
Food Webs: Complex networks of feeding relationships; energy flows from primary producers to various consumer levels.
Community Succession: Primary succession occurs on newly formed habitats; secondary succession follows disturbance.
Species Richness and Diversity: Influenced by disturbance, area, and proximity to other communities (island biogeography).
Example: Sea otters as keystone species in kelp forest communities.

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

Lectures 25-27: Ecosystems Ecology

Cycles of Matter, Energy Flow, and Biodiversity

Ecosystem ecology explores the movement of energy and matter through living and nonliving components, as well as the importance of biodiversity.

Cycles of Matter: The water, carbon, nitrogen, and phosphorus cycles move essential elements through ecosystems.
Net Primary Productivity (NPP): The rate at which plants convert solar energy into biomass, minus the energy used in respiration.
Biogeochemical Cycles: Each cycle has unique reservoirs and processes (e.g., nitrogen fixation, photosynthesis, decomposition).
Biodiversity: The variety of life at genetic, species, and ecosystem levels; provides ecosystem services and resilience.
Major Threats to Biodiversity: Habitat loss, invasive species, overexploitation, and climate change.
Mitigation: Conservation strategies include protected areas, restoration, sustainable resource use, and policy measures.
Example: Deforestation reduces carbon sequestration and threatens tropical biodiversity.

Biogeochemical Cycle	Main Reservoir	Key Processes
Water	Oceans	Evaporation, precipitation, transpiration
Carbon	Atmosphere, biomass	Photosynthesis, respiration, combustion
Nitrogen	Atmosphere	Nitrogen fixation, nitrification, denitrification
Phosphorus	Rocks, soil	Weathering, uptake by plants, sedimentation

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