Limiting FactorsEQ: How do the biotic and abiotic factors of an ecosystem

interact?https://www.youtube.com/watch?v=QI2ixJeIxEU&spfreload=10

What Limits Your Species?

1. Fit as many organisms (m&m’s) into your ecosystem (the box labeled “Carrying Capacity”) as you can without stacking them or overlapping over the sides

Count your organismsThis is your ecosystem’s carrying capacity.What is meant by carrying capacity?T-P-S

Types of Interactions

Look at the seaweed forest on the left.

How many fish do you count?

How many seaweed plants can you see?

Why do you think there are more members of the seaweed population than members of the fish population?

Interactions with the Environment

Most living things produce more offspring than will survive.

A female frog will lay hundreds of eggs in a small pond

In a few months, the frog population will not increase appreciably.

T-P-S – Why?

Organisms, such as frogs, interact with the biotic and abiotic factors in its environment.

The environment will control the size of its population

Limiting Factors

Populations cannot grow without stopping, because the environment has a limited amount of food, water, living space and other resources

Limiting Factors

A resource that is so scarce that it limits the size of a population is called a limiting factor.

FoodWaterSpace

Limiting Factors

Limiting factors are very closely tied to carrying capacity.

Many species of plants and animals can increase in number very quickly, and may exceed the carrying capacity of their habitat.

This results in stress, starvation, predation, parasites, and damage to the habitat.

Limiting Factors

Conditions that may limit the population of an ecosystem include, but are not limited to are:

DiseaseAccidentsNatural Factors (fires,

floods, etc.)StarvationHuntingPredation

Carrying Capacity

The largest population that an environment can support is known as its carrying capacity.

When a population grows larger than its carrying capacity, limiting factors in the environment cause individual organisms to die off and leave.

This causes a decrease in population

Limiting Factors & Carrying Capacity

For example, multiplying otters can quickly eat all of the fish in a stream.

With the fish gone, food becomes a limiting factor and the otters will starve or move to another area.

The stream now has a reduced carrying capacity for river otters until the fish population grows back again

Heads Together!

1. I will give you a question, then I will announce "Heads Together!“

2.Students stand up and lean in toward the others in your small group - literally heads together!

3.In your group, you will discuss answers to the question

4.After a minute or two, I will announce "Heads Apart!“

5.Students end their discussion and sit back down.

A resource that is so scarce that it limits the size of a population is called: __________________

Conditions that may limit the population of an ecosystem include, but are not limited to are:

Which resources may become so scarce that it limits the size of a population?

The largest population that an environment can support is known as its __________________

Why is it essential that the population of an ecosystem stay balanced?

What would happen if limiting factors didn’t exist?

InteractionsEQ: How do the biotic and abiotic factors of an ecosystem

interact?

Interactions

Nature is amazing! For the most part, it keeps itself balanced (homeostasis) without human interference.

An ecosystem can only support a certain number of organisms (its carrying capacity).

To keep this number in check, each organism within an ecosystem has a specific role, or niche to fill.

As a result of the interactions between organisms as they

carry out their roles, ecosystems generally stay balanced.

Limiting factors!

Interactions Between Organisms

Ecologists have described four main ways that species interact:

CompetitionPredator/PreySymbioticCoevolution

Competition

When two or more individuals or populations try to use the same resource such as food, water, shelter, space or sunlight, it is called competition

Ex: Buffalo competing for mates

One wins, the other loses

Competition

Because resources are in limited supply in the environment, their use by one individual or population decreases the amount of resources available to other organisms

Predator/Prey

Many interactions between species consist of one organism eating another.

The organism that is being eaten is the prey.

The organism that eats the prey is called the predator.

Ex: Lion and zebra

Predator/Prey

To survive, predators must be able to catch their prey.

To survive, prey must have methods and abilities to avoid capture.

These methods and abilities are called adaptations.

Symbiosis

Some species have very close interactions with other species.

Symbiosis is a close, long-term association between two or more organisms or species.

Symbiosis

In addition to the competitive relationships that help limit the population of an area, there are also cooperative relationships in an ecosystem that allow the habitat to function.

They are:

MutualismCommensalismParasitism

Mutualism

Mutualism is a symbiotic relationship in which both organisms benefit.

Example: Insects and plants

Insects get the tasty nectar

Flower gets pollinated

Commensalism

A symbiotic relationship where one organism benefits, and the other is unaffected is called commensalism

Example: Clownfish and sea anemone

Clownfish: protection

Anemone: doesn’t even notice

Parasitism

A symbiotic association in which one organism benefits and the other is harmed is called parasitism.

Example: Fleas and dogs

Fleas: food as it sucks blood from the dog

Dog: harmed

Interactions

A young girl is visiting her grandmother. The girl has noticed how her grandmother struggles to bend down to get things out of the lower cupboards.

The girl then decides to assist her grandmother with collecting utensils as they prepare dinner.

As the girl is helping, the grandmother notices the girl does not know some of the proper names of the utensils.

The grandmother then makes a learning game out of learning the utensils and then makes a song.

The two work together to prepare the meal.

What type of interaction? T-P-S

Interactions

You are seated in a class near a student. You do not “hang out” with this student, but you make conversation with him when he is here.

When he is in school, you do not benefit from him in any way. You are smarter, self-motivated, and social with others without him. When he is not here, you do not miss him.

He, on the other hand, returns from an absence and tells you he misses you. He always wants to be your partner, and without you, he does not socialize with others. He frequently asks you to help him.

Type of interaction? T-P-S

Interactions

You are walking through the woods and a tick bites you. The tick is carrying Lyme Disease. The bacteria are

transferred to you as long as the tick remains attached to your body as the tick sucks out your blood to feed itself.

You find the tick and remove it thinking nothing has happened.

Within a month, you see a rash around the bite site, and begin to run a fever. Other symptoms appear and you become very sick.

Interaction? T-P-S

Interactions

You and your dog are playing outside. You received the dog as a puppy when you were five

years old. Your dog misses you when you are gone and is always excited to see you when you return home. He sits on your lap when you watch TV and stroke his fur.

Sometimes you even talk to your dog as if he understands your deepest feelings.

Your dog is an important part of your life and you cannot imagine your life without him.

Type of interaction?T-P-S

Interactions

You are a hunter in need of providing your family with food.

You go out on a hunt for deer, much like a wolf goes hunting for rabbits.

Interaction?T-P-S

Coevolution

The Earth is not static, meaning that it stays the same, but instead it is dynamic, or constantly and continuously changing.

Because the Earth itself is dynamic, the organisms that inhabit the Earth must change as well, or they will evolve out.

Another relationship is called coevolution, which is when two different species who are interdependent evolve together in order to perpetuate the species.

Coevolution

The term coevolution is used to describe cases where two (or more) species reciprocally affect each other’s evolution.

So for example, an evolutionary change in the structure of of a plant, might affect the structure of an herbivore that eats the plant

This in turn might affect the evolution of the plant, which might affect the evolution of the herbivore...and so on.

Example: Ant and acacia tree

Coevolution

Some Central American Acacia species have hollow thorns and pores at the bases of their leaves that secrete nectar

These hollow thorns are the exclusive nest-site of some species of ant that drink the nectar.

But the ants are not just taking advantage of the plant—they also defend their acacia plant against herbivores.

This system is probably the product of coevolution:

The plants would not have evolved hollow thorns or nectar pores unless their evolution had been affected by the ants,

And the ants would not have evolved herbivore defense behaviors unless their evolution had been affected by the plants.

Assessment Prompt

Arrange the words Mutualism, Commensalism, and Parasitism in the center of your table.

Using your graphic organizer, categorize each example listed out on the cards in the baggie below the appropriate type of symbiosis

Summarizer

3-2-1

3 types of interactions

2 examples of an interaction between 2 biotic factors

1 possible outcome if limiting factors no longer existed