Chapters 4, 5, 6 Communities, Ecosystems, Biomes, Populations, Biodiversity, and Conservation

Vocabulary Keystone Species Ecological Succession Habitat Primary Succession Niche Pioneer Species Predation Secondary Succession Symbiosis Climax Community Mutualism Biosphere Commensalism Biodiversity Parasitism Geosphere Population Hydrosphere Carrying Capacity Atmosphere Exponential Growth Sustainability Limiting Factor Renewable Resource Density-Dependent Nonrenewable Resource Density-Independent Greenhouse Effect

Standards: 6A.1, 6A.2, 6B.1, 6B.2, 6C.1, 6D.1 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.

Keystone Species Keystone Species – single species that is vital to ecosystem stability. Affects the survival and abundance of many other species in its community.

Habitat and Niche Habitat – area where an organism lives  HOME Niche – role or position that an organism has in its environment  JOB How an organism meets its own needs. Two species with same niches cannot coexist in the same habitat

Relationships Among Organisms Organisms that live together constantly interact  shapes an ecosystem. Types of Interactions: Competitive Predator-Prey Symbiotic  3 types

Competition Two or more organisms need the same resource at the same time. Same species or different species. Organisms typically occupy the same niche. Compete for mates, food, space, etc. Strong survive and weak die  “Survival of the Fittest”.

Predation Predation – the act of one organism consuming another organism for food. Most species get their food by eating other organisms. Predators affect the size of prey populations. Predator – the hunter Prey – the hunted

Predation Population size of predators in an ecosystem is directly affected by the size of the prey population. Fluctuations are predictable. Prey increases  predator increases Prey decreases  predator decreases

How Organisms Reduce Predation

Symbiotic Symbiosis – close relationship that exists when two or more species live together  coevolution. Types: Mutualism Commensalism Parasitism

Mutualism Mutualism – both organisms benefit each other.

Commensalism Commensalism – one organism benefits and the other neither helped nor harmed.

Parasitism Parasitism – one organism benefits at the expense of another. Parasite  lives on or in an organism & feeds Host  organism that nourishment is taken from Usually the host is not killed

Types of Interactions Interaction Species A Species B Competition Harmed Predation & Parasitism Benefited Mutualism Commensalism Unaffected

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

Review: Calculate Population Density 2m 4m

Population Growth Population size affected by: Births Deaths # Leaving # Entering

Exponential Growth Exponential Growth – growth pattern in which the individuals in a population reproduce at a constant increasing rate. Under ideal conditions with unlimited resources. Graph  J-shape

Exponential Growth

Carrying Capacity Carrying Capacity – maximum number of individuals of a particular species that environment can support. Logistic Growth Logistic Growth – includes the influence of limiting factors on population growth Graph  S-shape

Regulation of a Population Limiting Factor – any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms  slows population growth. 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 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 Reestablishment of damaged ecosystem with 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

Review: Primary or Secondary Succession

Earth as a System Biosphere  all living organisms Geosphere  solid, rocky part (core  crust) Hydrosphere  water Atmosphere  gases All systems must interact efficiently to maintain an ecosystem.

Greenhouse Effect Greenhouse Effect – normal warming effect when gases trap heat in the atmosphere. Greenhouse Gases (CO2, O2, methane, water vapor)  trap heat energy & maintain temperature on Earth.

Rate of Photo-synthesis CO2 in Atmosphere Atmospheric CO2 Greenhouse Effect Avg. Global Temps. Plants Rate of Photo-synthesis CO2 absorbed by plants Higher temperatures and shifting climate patterns may change areas where crops grow best and affect the makeup of natural plant communities. Increase CO2 = increase rate of photosynthesis

Biodiversity Biodiversity – variety of organisms living in an area at the same time  includes # of different species and population size of each species. Genetic diversity – genes & pattern of variation Species diversity – variety & abundance of species Ecosystem diversity – variety of habitats Humans depend on Earth’s biodiversity & ecosystem resources (such as clean water & air) to survive. Biodiversity is highest near equator and in the ocean along the coasts in the Western Pacific.

Threats to Biodiversity Habitat Destruction Humans destroy & convert complex natural ecosystems into simple systems that do not support many species. Rainforests  1% lost each year due to logging & agriculture Wetlands destroyed  “waste areas” Habitat fragmentation – prevents organism from accessing its entire home range. Solution  build land bridges or corridors.

Threats to Biodiversity Invasive Species Living organisms not native to an ecosystem. Threats  decrease biodiversity, preying on native species, competition, disease, changing food webs, etc. Fire Ant Nile Crocodile Burmese Python

Threats to Biodiversity Pollution CO2 & other greenhouse gases, human wastes, chemicals

Threats to Biodiversity Human Population Growth Exponential growth world-wide Population reaches Earth’s carrying capacity due to: Water shortages Waste removal and pollution Food resources and land usage Imbalance of biogeochemical cycles

Threats to Biodiversity Overharvesting Resources are consumed at an unsustainable rate Examples: overhunting, excessive logging, overfishing

Ecological Restoration Process of assisting the recovery of an ecosystem that has been destroyed.

Human Impact Sustainability – humans survive indefinitely  balance between resources and carrying capacity. Factors that affect sustainability of humans: Population growth  increased diseases, food & water shortage Pollution & waste Consumption of resources  demand increases Renewable - production = consumption Food & water Nonrenewable - production = consumption Fossil fuels (coal, oil, natural gas)