Chapters 3, 4, 5 Communities, Biomes, Ecosystems Population Ecology Biodiversity and Conservation

Vocabulary Population Limiting Factor Density-Dependent Density-Independent Ecological Succession Primary Succession Secondary Succession Climax Community Biosphere Biodiversity Geosphere Hydrosphere Atmosphere Carrying Capacity Sustainability Renewable Resource Nonrenewable Resource Greenhouse Effect

Standards: 6.2, 6.3,6.5, 6.6 Objectives: Summarize how limiting factors affect population size. Classify various types of limiting factors. Summarize the processes of primary and secondary succession. Summarize how various aspects of an ecosystem are naturally maintained. Summarize how various human activities affect the geochemical cycles and processes of Earth.

Population Population – group of organisms belonging to the same species that live in the same area. – Described based on their: Size  # of individuals Density  # of individuals per area of space Distribution  arrangement

Calculate Population Density 2m 4m

Regulation of a Population Limiting Factor – any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms. – Examples: sun, climate, temperature, water, nutrients, fire, soil, space, etc. – A population is affected by limiting factors.

Types of Limiting Factors Density-dependent  occur more quickly in a crowded population than a small one. – Triggered by increases in population size – Examples: competition, predation, parasitism, disease. Density independent  occur regardless of the population size. – Reduces the size of all populations in the area by the same proportion. – Mostly abiotic factors, human activities, natural disasters.

Types of Limiting Factors Abiotic Factors  may be chemical or physical. – Examples: water, N, O, salinity, pH, nutrients, precipitation. Biotic Factors  all living components. – Examples: bacteria, fungi, plants, animals. Changes in abiotic or biotic factors may decrease OR increase the size of a population.

Ecological Succession Ecological Succession – series of changes in an ecosystem when one community replaces another community. – Continual process of change and replacement because of competition. – Occurs in ALL ecosystems. – Two Types: Primary  slower process Secondary  faster process

Ecological Succession

Primary Succession Occurs in an area that has not previously been inhabited. – Examples: Volcanic eruption exposes bare rock, glaciers retreat exposing bare rock, or a city street. – Pioneer species (first organisms) such as lichens (fungi and algae), mosses, & bacteria can grow without soil. – Pioneer species break rock into soil. – Fewest habitats for organisms. – Nutrients and soil added over time. – Small plants (ferns and shrubs) grow breaking rock into more soil.

Primary Succession (cont’d) – Plant seeds germinate and grow. – Over time more species grow and die  decomposition = more nutrients in soil and larger plants grow. – Plants change = animals change – Communities replace other communities – Climax Community – stable, mature forest community where there is little change in the composition of species.

Primary Succession

Secondary Succession Occurs in an area where there was a preexisting community and well-formed soil. – Examples: abandoned farmland, vacant lots, clear- cut forests, areas produced by forest fires. – Similar to primary succession in later stages (after soil has formed). – Disturbance occurs such as fire, hurricane, human activities and community is destroyed. – Ecosystem interacts to restore original conditions.

Secondary Succession

Earth as a System Biosphere  all living organisms – Biodiversity – variety of organisms living in an area Geosphere  solid, rocky part (core - crust) Hydrosphere  water Atmosphere  gases All system must interact efficiently to maintain an ecosystem.

Biosphere Organisms and their waste materials decompose by bacteria  nutrients recycled. Humans affect ecosystems & biogeochemical cycles. – Carrying Capacity – maximum population size that can be supported by the available resources. Sustainability – humans survive indefinitely  balance between resources and carrying capacity.

Biosphere (cont’d) Factors that affect sustainability of humans: – Population Growth  exponential worldwide Diseases, food & water shortages, pollution Less available fertile soil  agriculture Deforestation  destroying land  increase erosion – Technology  pollutes air, water, & land Agricultural, industrial, alternative energy technology – Consumption of Resources  demand increases Protect environment by reducing, reusing, recycling Renewable Resources  production = consumption – Examples: food, water, timber Nonrenewable Resources  production = consumption – Examples: fossil fuels

Geosphere Soils is constantly being eroded and generated. – Generated by weathering and decaying of organisms  creates soil. – Erosion is caused by soil moving from one location to another due to water, wind, or ice. – Plants allow soil production = soil erosion. Soils are composed of inorganic minerals, organic matter, water, and air. Soils allow succession to occur.

Hydrosphere Hydrologic Cycle maintained by the sun’s energy and the effect of weather. Hydrologic Cycle purifies water: – Evaporated water is pure – Water is filtered through the soil and rocks – Large particles settle out as water flows toward oceans

Atmosphere Plants (& other photosynthetic organisms) must produce enough oxygen for ALL organisms on Earth to maintain a balance of CO 2 and O 2. Ozone Layer (O 3 )  protects us from UV radiation Plants  O 2 Animals  CO 2 Air is cleaned after rain or snow fall  removes impurities (dust)  precipitation.

Atmosphere (cont’d) Greenhouse Effect – normal warming effect when gases trap heat in the atmosphere. – Greenhouse Gases (CO 2, O 2, methane, water vapor)  trap heat energy & maintain temperature on Earth. Atmospheric CO 2 Greenhouse Effect Avg. Global Temps. PlantsPhoto- synthesis CO 2 absorbed by plants Atmospheric CO 2