Download Guided Notes Ch 4, 5, 6

Ch 4, 5, 6 Guided Notes
Name _________________________________
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  ______________
• Niche – role or position that an organism has in its environment  ________
– How an organism meets its own needs.
– Two species with same niches cannot ___________ in the same habitat
Relationships Among Organisms
• Organisms that live together constantly interact  shapes an ecosystem.
• Types of Interactions:
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–
–
1) Competition
• Two or more organisms need the same _______________ at the same time.
– _______________ species or ________________ species.
– Organisms typically occupy the same niche.
– ________________________ for mates, food, space, etc.
– Strong survive and weak die  “_______________________________”
2) Predation
• Predation – act of one organism _____________ another organism for food.
– Most species get their food by __________________ other organisms.
– Predators affect the size of prey populations.
– _____________________ – the hunter
– _____________________ – the hunted
• Population size of predators in an ecosystem is directly affected by the size of
the prey population.
• Fluctuations are predictable.
– Prey increases  predator _____________________
– Prey decreases  predator _____________________
Symbiotic
• Symbiosis – close relationship that exists when two or more species live
together  ________________________
– Types:
•
•
•
3) Mutualism
• Mutualism – both organisms _______________ each other.
4) Commensalism
• Commensalism – one organism _________________ and the other neither
helped nor harmed.
5) Parasitism
• Parasitism – one organism benefits at the expense of another.
– ____________________  lives on or in an organism & feeds
– ____________________  organism that nourishment is taken from
• Usually the host is not killed
Types of Interactions
Population
• ________________________________ – group of organisms belonging to
the same species that live in the same area.
– Described based on their:
• __________________  # of individuals
• __________________  # of individuals per area of space
• _________________________  arrangement
Population Growth
 Population size affected by:
•
•
• # Leaving
• # Entering
Exponential Growth
• Exponential Growth – growth pattern in which the individuals in a
population reproduce at a constant ________________________ rate.
– Under ideal conditions with unlimited resources.
– Graph  ______________________
Carrying Capacity
• Carrying Capacity – ______________________ number of individuals of a
particular species that environment can support.
• Logistic Growth – includes the influence of limiting factors on population
growth
• Graph  ____________________
Regulation of a Population
• Limiting Factor – any abiotic or biotic factor that restricts the numbers,
reproduction, or distribution of organisms  _________ population growth.
– Examples: sun, climate, temp., water, nutrients, fire, soil, space, etc.
– A population is affected by __________________________
Types of Limiting Factors
• Density-dependent  occur more quickly in a _______________ population
than a small one.
– Triggered by _____________________ in population size
– Examples: competition, predation, parasitism, disease.
• Density independent  occur regardless of the _______________________
– Reduces the size of all populations in the area by the same proportion.
– Mostly abiotic factors, human activities, natural disasters.
• ___________________ Factors  may be chemical or physical.
– Examples: water, N, O, salinity, pH, nutrients, precipitation.
• ___________________ Factors all living components.
– Examples: bacteria, fungi, plants, animals.
– Changes in abiotic or biotic factors may decrease OR increase the size of
a population.
Ch 4, 5, 6 Guided Notes
Name _________________________________
Ecological Succession
• Ecological Succession – series of ______________________ in an ecosystem
when one community ______________________ another community.
– Continual process of change and replacement because of competition.
– Occurs in ____________ ecosystems.
– Two Types:
• Primary  _______________________ process
• Secondary  ______________________ process
Primary Succession
• Occurs in an area that has not previously been ________________________.
– Examples: Volcanic eruption exposes bare rock, glaciers retreat
exposing bare rock, or a city street.
– Pioneer species (___________________________________) such as
lichens (fungi and algae), mosses, & bacteria can grow without soil.
– _____________________________ species break rock into soil.
– ___________________________ habitats for organisms.
– Nutrients and soil ___________________________ over time.
– Small plants (ferns and shrubs) grow breaking rock into more soil.
– Plant seeds germinate and grow.
– Over time more species grow and die  _________________________
= more nutrients in soil and larger plants grow.
– Plants change = _________________________ change
– Communities replace other communities
– ___________________________________ – stable, mature forest
community where there is little change in the composition of species.
Secondary Succession
• _________________________ 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).
– __________________________________________ occurs such as fire,
hurricane, human activities and community is destroyed.
– Ecosystem interacts to restore _______________________ conditions.
Earth as a System
•
•
•
•
•
___________________________  all living organisms
___________________________  solid, rocky part (core  crust)
___________________________  water
___________________________  gases
All systems must interact efficiently to maintain an ecosystem.
Greenhouse Effect
• Greenhouse Effect – normal ___________________________ effect when
gases trap heat in the atmosphere.
– _____________________________________ (CO2, O2, methane, water
vapor)  trap heat energy & maintain temperature on Earth.
CO2 in Atmosphere
• 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 _________________________________
Atmospheric Greenhouse
CO2
Effect
Avg.
Global
Temps.
Plants
Rate of
CO2
Atmospheric
Photosynthesis Absorbed
CO2
by Plants
Biodiversity
• Biodiversity – _________________ of organisms living in an area at the same
time  includes # of different species & population size of each species.
– _______________________ diversity – genes & pattern of variation
– _______________________ diversity – variety & abundance of species
– _______________________ diversity – variety of habitats
• Humans depend on Earth’s biodiversity & ecosystem resources (such as clean
water & air) to ________________________.
Threats to Biodiversity
1. _________________________________________
– Humans destroy & convert complex natural ecosystems into simple
systems that do not support many species.
– __________________  1% lost each year due to logging & agriculture
– __________________ destroyed  “waste areas”
– ________________ fragmentation – prevents organism from accessing
its entire home range. Solution  build land bridges or corridors.
2. Invasive Species
– Living organisms not ____________________ to an ecosystem.
– ______________________  decrease biodiversity, preying on native
species, competition, disease, changing food webs, etc.
3. ________________________________
– CO2 & other greenhouse gases, human wastes, chemicals
4. Human Population Growth
– _________________________________ growth world-wide
– Population reaches Earth’s ______________________________ due to:
• Water shortages
• Waste removal and pollution
• Food resources and land usage
• Imbalance of biogeochemical cycles
5. Overharvesting
– Resources are consumed at an _____________________________ rate
– Examples: overhunting, excessive logging, overfishing
Ecological Restoration
• Process of assisting the _____________________________ of an ecosystem
that has been destroyed.
Human Impact
• ___________________________________ – 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 _________________________
• Renewable - production ____ consumption
– Food & water
• Nonrenewable - production ____ consumption
– Fossil fuels (coal, oil, natural gas)