Unit 2 Review - AP Environmental Science
Unit 2 Review - AP Environmental Science
Importance of Preparation
Ensure that the ultimate review packet study guide is printed and ready.
Answer practice questions to confirm understanding of Unit 2 concepts.
Familiarize with the writing style necessary for the AP Environmental Science exam through mini FRQs at the end of each unit.
Topic 1: Biodiversity
Definition of Biodiversity: The diversity of different life forms found within an ecosystem.
Three Levels of Biodiversity:
Genetic Biodiversity:
Refers to the variance of genes or traits within individuals of a population.
High genetic diversity increases likelihood of adaptation to environmental disturbances (e.g., drought conditions).
Example: Sparrows with larger beaks may survive better in drought conditions affecting food sources.
Species Biodiversity:
Diversity of different types of organisms within an ecosystem.
Measured by two methods:
Species Richness: Count of total different species present in an ecosystem.
Species Evenness: Distribution and balance of population sizes among species.
Example: Two forests may have the same species richness, but one forest having more even distribution prevents potential biodiversity loss.
Ecosystem Biodiversity:
Refers to the variance of different ecosystems within a geographic area.
Example: Tropical rainforests exhibit high ecosystem diversity compared to deserts.
Topic 2: Benefits of Biodiversity to Ecosystems and Humans
Biodiversity is crucial for ecosystem function and resilience.
Ecosystem Services: Categorized into four types,
Provisioning Services:
Resources directly obtained from natural ecosystems (e.g., wood).
Supporting Services:
Processes that maintain ecosystem functions (e.g., pollination by bees enhances agricultural productivity).
Regulating Services:
Natural ecosystem functions that stabilize environmental factors (e.g., trees sequester CO₂, mitigating climate change impact).
Cultural Services:
Non-material benefits gained from ecosystems (e.g., recreation, tourism, research).
Example: The Deepwater Horizon oil spill disrupted these services, harming fishing, tourism, and coastline stability.
Topic 3: Island Biogeography
Principles of Island Biogeography:
Proximity to the mainland affects species richness; closer islands support more species due to higher colonization rates.
Size of the island affects species richness: larger islands support more species due to varied habitats.
Graphs:
Inverse relationship between distance from mainland and species richness.
Direct relationship between island area and species number.
Unique Adaptations: Island ecosystems promote specialized adaptations due to limited resources.
Example: The extinction of the dodo bird resulted from its evolutionary path leading to vulnerability against human intrusion and invasive species.
Topic 4: Ecological Tolerance
Definition: The range of environmental conditions an organism can endure.
Example of Human Body Temperature:
Optimal range: 97°F to 99°F.
Outside this range, individuals may enter zones of physiological stress and intolerance, facing serious health issues.
Genetic Diversity Importance: Variance within populations can enhance tolerance levels, promoting survival during environmental changes.
Topic 5: Natural Disturbances and Climate Change
Types of Events Disrupting Ecosystems:
Periodic Events: Regular events (e.g., seasonal rains).
Episodic Events: Irregular yet predictable events (e.g., hurricanes).
Random Events: Unpredictable occurrences (e.g., asteroid strikes).
Malankovitch Cycles:
Describe natural changes in Earth's orbit affecting climate over tens of thousands of years.
Distinct cycles:
Eccentricity: Variations in the shape of Earth's orbit.
Axial Precession: Changes in how Earth's axis wobbles.
Obliquity: Variations in the tilt of Earth's axis.
Gradual climate changes impact sea levels, affecting coastal and coral reef ecosystems.
Topic 6: Adaptation and Extinction
Definition of Adaptation: Genetic changes in a species that improve survival and reproduction.
Example: The evolution of opposable thumbs in Homo habilis improved tool-making abilities, providing survival advantages.
Organisms that cannot adapt to environmental disturbances may face extinction.
Example: Early hominids adapted to grassland expansions provided an evolutionary advantage over competing species.
Topic 7: Ecological Succession
Types of Succession:
Primary Succession:
Begins with pioneer species (e.g., moss) colonizing bare rock.
Through weathering, soil formation occurs, allowing diverse plant growth over time.
Secondary Succession:
Occurs in disturbed soil with existing vegetation.
Pioneer species like grasses grow quickly after disturbances (e.g., wildfires).
Climax Communities: Stable, mature ecosystems with high biomass and species richness.
Topic 8: Keystone Species and Ecosystem Function
Keystone Species Definition: A species vital for maintaining ecological balance; their removal can lead to ecosystem collapse.
Examples:
Wolves: Control deer populations, ensuring plant life remains stable.
Beavers: Create ponds; their absence can alter entire landscapes.
Conclusion
This comprehensive review provides insights into the various themes of biodiversity, its benefits, influences on ecosystems, and the implications of ecological concepts.
Reflect on how these concepts interconnect to build a better understanding in AP Environmental Science studies.
Unit 2 Review - AP Environmental Science
Importance of Preparation
Ensure the review packet study guide is printed and ready.
Answer practice questions to confirm understanding of Unit 2 concepts.
Familiarize with the AP Environmental Science exam writing style through mini FRQs.
Topic 1: Biodiversity
Definition of Biodiversity: The diversity of different life forms within an ecosystem.
Three Levels of Biodiversity:
Genetic Biodiversity: Variance of genes/traits within a population. High diversity aids adaptation.
Example: Sparrows with larger beaks surviving drought.
Species Biodiversity: Diversity of different organisms in an ecosystem.
Measured by: Species Richness (total different species) and Species Evenness (distribution of population sizes).
Example: Two forests with same richness, but one with even distribution is more stable.
Ecosystem Biodiversity: Variance of different ecosystems within a geographic area.
Example: Tropical rainforests have high ecosystem diversity.
Topic 2: Benefits of Biodiversity to Ecosystems and Humans
Biodiversity is crucial for ecosystem function and resilience.
Ecosystem Services: Categorized into four types:
Provisioning Services: Resources directly obtained (e.g., wood, food).
Supporting Services: Processes maintaining ecosystem functions (e.g., soil formation, pollination).
Regulating Services: Natural functions stabilizing environmental factors (e.g., CO
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sequestration, flood control).Cultural Services: Non-material benefits (e.g., recreation, research).
Example: Deepwater Horizon oil spill harmed fishing, tourism, and coastline stability.
Topic 3: Island Biogeography
Principles of Island Biogeography:
Proximity to mainland: Closer islands have more species (higher colonization).
Island size: Larger islands have more species (varied habitats, larger populations).
Graphs:
Inverse relationship: Distance from mainland vs. species richness.
Direct relationship: Island area vs. species number.
Unique Adaptations: Island ecosystems foster specialized adaptations due to unique pressures.
Example: Dodo bird's extinction due to vulnerability to human intrusion and invasive species.
Topic 4: Ecological Tolerance
Definition: The range of environmental conditions an organism can endure.
Example of Human Body Temperature:
Optimal range: to .
Outside optimal range: Zones of physiological stress and intolerance.
Genetic Diversity Importance: Enhances tolerance and survival during environmental changes.
Topic 5: Natural Disturbances and Climate Change
Types of Events Disrupting Ecosystems:
Periodic Events: Regular (e.g., seasonal rains).
Episodic Events: Irregular yet predictable (e.g., hurricanes).
Random Events: Unpredictable (e.g., asteroid strikes).
Milankovitch Cycles: Natural changes in Earth's orbit affecting climate over tens of thousands of years.
Eccentricity: Variations in Earth's orbit shape.
Axial Precession: Changes in Earth's axis wobble.
Obliquity: Variations in Earth's axis tilt.
Gradual climate changes impact sea levels, affecting coastal and coral reef ecosystems.
Topic 6: Adaptation and Extinction
Definition of Adaptation: Genetic changes in a species that improve survival and reproduction.
Example: Opposable thumbs in Homo habilis improved tool-making.
Organisms unable to adapt to disturbances may face extinction.
Example: Early hominids adapted to grassland expansions, gaining an evolutionary advantage.
Topic 7: Ecological Succession
Types of Succession:
Primary Succession: Begins with pioneer species on bare rock (e.g., moss) and forms soil over time.
Secondary Succession: Occurs in disturbed soil with existing vegetation (e.g., grasses after wildfires).
Climax Communities: Stable, mature ecosystems with high biomass and species richness.
Topic 8: Keystone Species and Ecosystem Function
Keystone Species Definition: A species vital for maintaining ecological balance; their removal can cause ecosystem collapse.
Examples:
Wolves: Control deer populations, stabilizing plant life.
Beavers: Create ponds, altering landscapes and habitats.
Conclusion
This review covers biodiversity, its benefits, influences on ecosystems, and ecological concepts.
Reflect on how these concepts interconnect for AP Environmental Science studies.