4.3 ECOLOGICAL SUCCESSION Biosphere Ecosystems Communities Populations Organisms.
What Factors Affect Populations in Ecosystems?
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WHAT FACTORS AFFECT POPULATIONS IN ECOSYSTEMS? Text 1.3: 36-40
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What Factors Affect Populations in Ecosystems?. Text 1.3: 36-40. Agenda. Minds On – Activity: Keeping a Balance How Do Organisms Interact? Competition Species Niche Predation Mimicry Symbiosis Inquiry Task – Symbiosis At Its Best! Limiting Factors & Carrying Capacity - PowerPoint PPT Presentation
Transcript of What Factors Affect Populations in Ecosystems?
WHAT FACTORS AFFECT POPULATIONS IN ECOSYSTEMS?Text 1.3: 36-40
Agenda1. Minds On – Activity: Keeping a Balance2. How Do Organisms Interact?
Competition Species Niche Predation Mimicry Symbiosis
3. Inquiry Task – Symbiosis At Its Best!4. Limiting Factors & Carrying Capacity5. Case Study – Lynx & Hare6. Consolidation – Analyze This!
Learning Goal
By the end of the class I can Describe biotic relationships within an
ecosystem Describe how these interactions effect the
populations within the ecosystem
Minds On – Keeping a Balance Goal – organisms have to find resources in order
to survive Food = hand over stomach Water = hand over mouth Shelter = hands over head to make roof
Debrief What are some factors that affected the survival of
animals? Did you notice any trends? Did the animal population, rise, fall or stay the same?
Round1
Round 2
Round 3
Round 4
Round 5
Round 6
Round 7
Round 8
Round 9
Animal
How Do Organisms Interact? Competition The interaction of two or more
organisms competing for the same resources within a given habitat May compete to mate, for
resources, for preferable habitat, etc.
May result in slightly different species having slightly different niches EX. Warblers
What is a Species Niche? Niche -
organism’s use of the biotic and abiotic resources in an environment.
Competitive Exclusion Principle – two species in direct competition cannot occupy the same niche.
What Are the Effects of Competition?
How Do Organisms Interact?Predation When an organism eats another as
a food source Both predator and prey have
adapted strategies to help them hunt or prevent them from being hunted Predator: Hawks have fabulous
eyesight to aid in hunting Prey: Porcupines have quills to
prevent predators from wanting to attack them
How Do Organisms Prevent Predation?
Mimicry of monarch butterfly by the victory butterfly Both taste bad and similar marking make
predators avoid both
How Do Organisms Prevent Predation?
Owl ButterflyMimics the eyespots of an owl to scare off predators
Leaf ButterflyCamouflages in leaf
litter on the forest floor
What is Symbiosis? Many organisms are involved in symbiotic
relationships with other organisms Mutualism
Win- win EX: Clownfish and sea anemones
Parasitic Win- Loose Tick and Humans
Commensalism Win- Neutral Spider and plants
What is Symbiosis? Many organisms are involved in symbiotic
relationships with other organisms
Inquiry Task – Symbiosis At It’s Best! Research one example of a unique
symbiotic relationship between two species: Brief description of species involved Type of symbiotic relationship Visual information either a picture/video
How Can We Describe Populations?
Equilibrium – number of deaths equals the number of births
How many people can
the world sustain? What limits human
population?
How Can We Describe Populations?
As a population grows each individual gets a smaller share of the resources
Organisms become stressed, some die, some are not able to reproduce.
Eventually the number of births is equal to the number of deaths = Equilibrium.
Carrying Capacity = the maximum number of individuals that an ecosystem can support without reducing its ability to support future generations of species.
What would cause a species to
reach its carrying capacity?
What Can Limit Population Size?
Limiting Factor – is an environmental factor that prevents an increase in the number of organisms in a population or prevents them from moving into new habitats.
Healthy populations have limiting factors that prevent overpopulation.
In order for population to be stable or sustainable it must never exceed its carrying capacity.
What is an example of an abiotic limiting factor?What is an example of a biotic limiting factor?
Case Study – Lynx & Snowshoe Hare
As population of hares (prey) increases the lynx can capture hares more easily.
Lynx = well feed increased offspring population increases.
Increase in Lynx causes a decrease in hare population due to predation.
As lynx food supply runs out lynx population will decrease
Finally fewer lynx causes hare population to begin to rebound or recover and the cycle continues.
What Else is Going On?In the perfect world we would see this ideal population cycle, however there is always more to the story. Read the case study and determine what other factors may impact the populations.
Consolidation – Analyze This!
Look at the graph and determine the following: Carrying
capacity Limiting factors Trends Anomalies What is going on in
this population of Canadian Cod?
