APES 1-3 Biology Past Paper Review 2024 PDF

Unit 1: The Living World – Ecosystems 1.1 Ecosystems Biotic (living) and abiotic (non-living) components. Biomes: Defined by temperature and precipitation. Examples: Rainforests, deserts, tundras. 1.2 Energy Flow Producers (autotrophs), consumers (heterotrophs), and decomposers. Food chains/webs:...

Unit 1: The Living World – Ecosystems 1.1 Ecosystems Biotic (living) and abiotic (non-living) components. Biomes: Defined by temperature and precipitation. Examples: Rainforests, deserts, tundras. 1.2 Energy Flow Producers (autotrophs), consumers (heterotrophs), and decomposers. Food chains/webs: Energy transfer, 10% rule (energy decreases up trophic levels). Gross Primary Productivity (GPP) vs. Net Primary Productivity (NPP). 1.3 Cycling of Matter Water cycle: Evaporation, condensation, precipitation. Carbon cycle: Photosynthesis, respiration, fossil fuels, ocean absorption. Nitrogen cycle: Fixation, nitrification, assimilation, ammonification, denitrification. Phosphorus cycle: Sedimentary process, no atmospheric phase. 1.4 Trophic Levels Producers → Primary consumers → Secondary consumers → Tertiary consumers. Keystone species: Essential for ecosystem stability. Trophic cascades: Changes at the top affect lower levels. 1.5 Natural Biogeochemical Processes Decomposition, weathering, and sedimentation. Energy sources: Solar, chemical (chemosynthesis). Unit 2: The Living World – Biodiversity 2.1 Introduction to Biodiversity Types of biodiversity: Genetic, species, and ecosystem diversity. Importance: Resilience, ecosystem services, adaptability. 2.2 Ecosystem Services Provisioning: Food, water, timber. Regulating: Climate control, water purification. Cultural: Recreational, aesthetic, spiritual. Supporting: Soil formation, nutrient cycling. 2.3 Island Biogeography Theory of Island Biogeography: Size and distance from mainland affect biodiversity. Edge effects: Habitat fragmentation impacts species. 2.4 Ecological Tolerance Range of conditions an organism can withstand (e.g., temperature, salinity). 2.5 Adaptations Evolution through natural selection. Specialists vs. generalists: Narrow vs. broad niches. 2.6 Ecological Succession Primary succession: Starts with no soil (e.g., volcanic eruption). Secondary succession: Soil present (e.g., after forest fire). Climax communities: Stable, final stage. Unit 3: Populations 3.1 Generalist vs. Specialist Species Generalists: Broad range of conditions (e.g., raccoons). Specialists: Narrow niches, specific needs (e.g., koalas). 3.2 K-Selected vs. r-Selected Species K-selected: Few offspring, high parental care (e.g., elephants). r-selected: Many offspring, little care (e.g., insects). 3.3 Survivorship Curves Type I: High survival early, die later (humans). Type II: Constant death rate (birds). Type III: High early death, survivors live long (trees). 3.4 Carrying Capacity Maximum population environment can support (resources limit growth). 3.5 Population Growth and Resource Use Exponential growth: J-shaped curve. Logistic growth: S-shaped curve, reaches carrying capacity. 3.6 Age Structure Diagrams Pyramid-shaped: Growing population. Stable-shaped: Steady population. Inverted pyramid: Declining population. 3.7 Human Population Dynamics Birth/death rates, immigration/emigration affect growth. Demographic Transition Model (DTM): Stages of population change (pre-industrial to post-industrial). 3.8 Impacts of Population Growth Overpopulation: Strain on resources, pollution. Urbanization: Habitat loss, heat islands.