4-2 What Shapes an Ecosystem? Ecosystems are shaped by Biotic (living) & Abiotic (nonliving)...
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Transcript of 4-2 What Shapes an Ecosystem? Ecosystems are shaped by Biotic (living) & Abiotic (nonliving)...
4-2 What Shapes an Ecosystem?
Ecosystems are shaped by Biotic (living) & Abiotic (nonliving) factors.
Biotic factor=living organisms in the ecosystem Abiotic factors= physical (nonliving) components of the
ecosystem & how the organism uses these components.Area where an organism lives=habitat
The NicheNiche-the combined physical and biological
conditions in which organisms live & how the organism uses these conditions.
A Niche includes:– The food type, method to obtain it and competition for the
food.– Temperature and water content.– Reproductive time and location
Community Interaction:
Competition- a conflict for the same resource in a habitat at the same time.
Resource- any necessity for life.
Symbiosis: two organisms living close together. There are three types.
1) Mutualism2) Commensalism3) Parasitism
Symbiosis: Commensalism: One member benefits & one is
neither helped nor harmed.
Barnacles on a whale
Flatworm on horseshoe crab
Type of relationship
Species harmed
Species benefits
Species neutral
Commensalism
Parasitism
Mutualism
= 1 species
Symbiosis:
Ecological SuccessionEcosystems &
communities are ALWAYS changing!
Ecological Succession= a series of predictable changes in a community.1) Primary succession
2) Secondary succession
Primary succession: occurs in areas with no soil.
Example= Volcanic eruptions, glacial melts.
Ecological Succession
Ecological SuccessionSecondary succession: succession following a disturbance that
destroys a community without destroying the soil.Ex: destructed through fire, natural disasters, or clearing of land
Chapter 5-1: How Populations Grow
Populations have 3 characteristics:-- Geographic distribution-- Population Density -- Growth rate.
Characteristics of a Population
Geographic Distribution (range) is the area a population inhabits. (Where it lives.)
Growth rate is the rate at which members are added or removed from the population.
Characteristics of a Population
Population GrowthThree factors affect population size: birth rate, death rate, and migration.Growing population= a higher birth rate than death rate.Shrinking populations= a higher death rate than birth rateStable populations have equal birth & death rates
Population’s growth slows down or stops
Carrying Capacity: the largest number of individuals a given
environment can hold
Density Dependent Factor
A limiting factor that depends on the population size= Density Dependent Limiting Factor.
Types of Density Dependent Factors:--Competition--Predation--Parasitism & Disease
Density Dependent Factor
2) PREDATION: Predation creates the predator-prey relationship.
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Moose Wolves
6-3 BiodiversityVariety= Diversity Biodiversity- the sum total of the variety of
organisms in the biosphere. Human activity can reduce biodiversity by
altering habitats: 1) Hunting species to extinction 2) Introducing toxic chemicals into food webs
Pollution
DDT= one of the first widely used pesticides.
GOOD BAD
CheapRemains active for a long timeKills many different insects Controls agricultural pests.
-Non biodegradable-Organisms can NOT remove it from their bodies.-DDT gets stored in organisms (producers & consumers bodies)
Pollution As you move up trophic levels in a food chain the
amount of DDT consumed increases GREATLY! Biological Magnification- concentrations of a
harmful substance increases at higher trophic levels.
Plants pick up DDT from water& store it
Herbivores eatplants and storesome DDT
Carnivores eatherbivores and store more DDT
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