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Transcript of Ecology

What limits a populations growth?
Levels of Organization
The largest level is the biosphere, which refers to the thin layer on earth where life is found.
Population Dynamics

Includes organisms and environment they live.
Coral Reef
All of the organisms living within an ecosystem or area.
All of the individuals of a
single species in one place.
The smallest level of organization in Ecology.
A typical representation
of Ecology organization
What is...
a flock of geese

a mountain stream

the organisms living in and by the stream

a single minnow

the 20km thick layer that life occurs in

What is being used to classify these factors?
Amount of rainfall
Amount of sunlight
Length of winter
amount of nitrogen
number of parasites
number of predators
number of prey
What is your habitat?
Biotic factors and Abiotic Factors

-Of your habitat

-One of your animal's habitat

Coral Reef
What is a niche?
What niche do these two have?
What niche do plants have? fungi?
Niche- an organisms way of life within an ecosystem

-Social Animals

Ecosystems are related from top to bottom and bottom to top.

What happens the the community when there is a year with no rain?
What can make a population change?
Birth Rate-
Death Rate-
Life Expectancy-
So if you have a population of pigeons that have a population of 100 and they
have a mortality rate of 12 deaths per year and 10 births per year.

What is the expected yearly growth rate per year?
Limiting factors
and more depending on the organism
What would a growth model look like if we took limiting factors in mind?
Logistic growth model: a model that takes limiting factors into account.
What happens to
the logistic growth line
when it reaches K?
K represents the _____
What would the population of grass look
like if there were no herbivores?

What would the population of grass look
like if there were herbivores?

What would the population of herbivores
look like?

Life Expectancy and Populations
Survivorship Curves

When resources are shared, there
is _________ between species and within species.
Competitive Exclusion
One species is better adapted to acquire resources, grow and reproduce
The other species is slowly/quickly replaced by the better adapted species.
What is Ecology?
What are the levels of organization?
What are abiotic and biotic factors
How do they affect a population?
Why are population models used?
Coexistence can occur when two organisms can exist despite interactions.
How do populations of producers, herbivores, carnivores, and decomposers influence each others populations?
Population Changes
Does a forest fire affect a large population the same as it would a small population?
Does an increase in average temperature affect populations of all sizes?
Does a shortage in water affect a large population in the same way it would affect a small population?

Logistic growth is controlled by limiting factors.
Limiting factors_____________________

Density _________ factors
Floods, Fires, Regional heating/cooling
Factors that ____________________

Density _________ factors
Food/Water shortages, space shortage
Factors that ____________________
Population Fluctuations
are _______________
What type of factor is driving these population changes?
How do you know?
New/current population
problems in the US-

White nose fungus
among bats that hibernate in caves.

Why are bats important to this biome/regoin of the US?

$3.7 Billion Dollars/year
Small Populations

Genetic diversity is _________
__________(mating with relatives) is increased
This leads to less diversity, which lowers the ability of a species to __________ to changing conditions
These offspring are also more susceptible to disease
Human Population
How has it changed in the
last millennium?


What should we expect?
Human population growth
varies from country to country.


What could cause this?
20 percent of countries are well developed

Meaning these countries __________________

80 percent of countries are still developing

These counties are much poorer, _____________
When will the human
population growth level out?
A study published in June by researchers at the University of Arizona, for example, found that many of the planet's animal species -- from amphibians, birds and crocodilians to mammals, squamates and turtles -- have proved quite adaptable to changes in average temperature that unfolded at a rate of about 1-degree Celsius per million years.
If they hope to adapt to current climatic changes, however -- including the potential for average temperature increases of 4-degrees Celsius over the next 100 years -- the same species would need to evolve 10,000 to 100,000 times faster.
Levels of Ecology

Population Changes and Models

Human Growth and Effects
Topics covered so far
Topics to Cover

Why are models important?

What are some types of models we have learned about and how could they be used?
Species Interactions
Predator and Prey
-survival of a predator depends on ______
-survival of prey depends on ___________
-All are considered to be forms of consumers
1. Producers
2. Consumers
All organisms have a niche that they fill in their ecosystem. NO ecosystem can survive without at least one of these.
Nutrient and Energy Cycling
Organisms that can make their own
energy using photosynthesis or
Other Relationships


Break down and recycle organic matter
-Where do they fall in a food chain?
Can we keep track of how energy is transferred?
Trophic levels let us look at general groups of organisms and where they fit in the sequence of energy transfer

_______ shows how energy is transferred through a series of organisms

_______show how food chains are interlinked within an ecosystem
An example:

A plant absorbs 1000 calories of energy from the sun.

A cow eats the plant, breaks it down and absorbs only a fraction of the energy stored in the plant. Some of the plant material is ________________
Some of the energy in the plant is lost____________
The energy absorbed by the cow is ___________
What else is transferred from our food to us?
Carbon Cycle
Nitrogen Cycle
Nitrogen is abundant in the atmosphere, but many plants and animals cannot breath it in and use it.
How does carbon flow from the atmosphere to us?

How is carbon returned to the atmosphere from us?

Are human actions affecting the carbon cycle?
Humans effect on the biosphere:
What else besides energy will flow through an ecosystem?

What is the primary source of energy for the earth?
Energy flow is the flow of energy from one organism to the next.

How is the energy transferred?

How can we show this in a model?
Carbon Cycle Out of Balance
Extra carbon can be expelled into the atmosphere by ______________________

Decreasing ____________ will lower the rate that carbon is captured from the atmosphere.
Legumes are plants that form ____________ relationships with
____________fixing _____________
Levels of Ecology
Factors of an Ecosystem
Growth Models
Human Population
Community Interactions
Chemical and Energy Cycles

What is ecology?

What are the levels of organization in ecology?
How is an ecosystem different from a community?

What are factors within an ecosystem that effect living organisms?
What are factors that affect population growth within an ecosystem?

How do you find the growth rate for a population?
What does this model show?

How can a population grow like this?

How is it useful?

What grows like
What does this model show?

What causes a population to grow like this?

How is this type
of growth
different than
What would happen if a new species moved in that used the same source of food?

What would happen if there was a major decrease in the
predator population?

What would happen if there was a major natural disaster within the ecosystem?
How is this model useful?
What does this type of model show?

How is it useful?

Which population is growing the fastest?
When did the human population "take off"?

What are some attributes to this change?

What should happen to human population growth
over time?

Do all countries grow at the same rate?

Which countries are growing the fastest? Why?

Which countries are very slow growing?

How does the growth of the United States compare?
How do populations interact within a population?
An organisms role________
Who makes energy?

Who consumes?

How are these organisms categorized?

How can we show these types of relationships in a diagram?

How does an energy pyramid organize animals?

What percent of energy is
What trophic level contains the most energy?

What trophic level contains the most organisms?

Why do food chains end?

What else is transferred along a food chain?

Your assignment:

Pick 5 different animals from 5 different ecosystems.

Make a concept map that shows how they fit into the biosphere.
***All levels need to be drawn***
Habitat- the environment where an
organism lives.
Organisms that ________________________.
__________-show the relationship between energy, number and type of organism.

As you grow, the enrgy
in the food you eat is
used to build parts of
your body.
(energy passed to your level)
What happens to the rest of the energy?

Why are food chains, food webs and energy pyramids
important models to study?
Abiotic Factors-
Biotic Factors-
Trying it out

1. Create 4 different food chains that each contain four animals

2. Create a food web that contains 10 animals total

3. Create a food pyramid using the animals from your food web
So populations that make up each level constantly

Bottom levels get energy from the _______

Levels above the bottom level __________

Do populations of animals and plants grow forever?
Exponential growth model- populations grow
without limits. Ex _____
Types of Relationships

Symbiosis- living together in very close relationships

Symbiotic Relationships



1. Draw a relationship and then make a drawing
in one of your squares. See if other students can
guess the type of relationship

2. Repeat until you have all four relationships
Predator-Prey, Mutualism, Commensalism, Parasitism

Turn to pg 453 and read the problem for 24-27
Who benefits?
Who loses?
Nutrient Cycles
-From a pond to the earth three key ingredients are always being passed
_________, __________, ___________
The Water Cycle
Every living thing needs water to live
How do humans
change the water




All of these are important ways that carbon is transferred on earth.
It is fixed by plants and
bacteria to make protein

Full transcript