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

2. 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

3. 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.

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

5. 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

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

7. 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”.

8. 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

9. 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

10. How Organisms Reduce Predation

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

12. Mutualism
Mutualism – both organisms benefit each other.

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

14. 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

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

16. 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

17. Review: Calculate Population Density2m 4m

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

19. 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

20. Exponential Growth

21. 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

22. 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.

23. 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.

24. 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.

25. 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

26. Ecological Succession

27. 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.

28. 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.

29. Primary Succession

30. 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.

31. Secondary Succession

32. Review: Primary or Secondary Succession

33. 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.

34. 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.

35. 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

36. 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.

37. 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.

38. 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

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

40. 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

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

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

43. 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)