survivor: who will be the best competitor? how environmental change affects competition

Survivor:

Who Will Be the Best Competitor?

How environmental change affects competition

Competition

• Organisms require resources from their environment to grow, survive and reproduce

• Plants in the rainforest require sunlight, water and nutrients

• Different species of plants compete for these resources

Competition Examples

http://www.youtube.com/watch?v=d26AhcKeEbE&feature=related

Within Species Competition VideoClover sprouts compete above and below ground.

Between Species Competition VideoDamselfish defend territories to compete with other fish.

http://www.youtube.com/watch?v=9YR7VfsR5iA&feature=related

Competition Examples

Competition Examples

What examples of competition can you think of?

Why is it important to understand competition?

• Predict if species can coexist• Predict what will happen if – species are lost (extinction)– species are introduced• Invasive species• Biological controls

Environmental Change = Competition Change

If global warming decreased rainfall, • how would that affect plant competition?

Sea lamprey are an invasive species that attack fish and suck their blood.

If sea lamprey, invade Lake Michigan• how would that affect fish competition?

Species Loss in Stickleback Fish

• Historically 2 species that differ in– Color, size, shape, behavior– Feeding & mating habitats

• One species mates in the open; the other species mates in the vegetation

Invasive Species Changed Mating Habitats

• Recent crayfish introduction

Historical Conditions Current Conditions

• Ecological changes:- Vegetation loss- Increased turbidity- Water color

Loss of habitat increased species competition

• Bigger males compete better

• Bigger males = more aggression = gain a territory

• Need a territory to build a nest and attract females

0 1 2 3 4 5-0.02

-0.01

0

0.01

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After habitat loss

Before habitat loss

Male Size Rank

Ag-gres-sion

largest smallest

Loss of habitat increased species competition

0 1 2 3 4 5-0.02

-0.01

0

0.01

0.02

0.03

After habitat loss

Before habitat loss

Male Size Rank

Ag-gres-sion

largest smallest

Loss of habitat increased species competition

Benthic Species

Limnetic Species

0 1 2 3 4 5-0.02

-0.01

0

0.01

0.02

0.03

After habitat loss

Before habitat loss

Male Size Rank

Ag-gres-sion

largest smallest

Loss of habitat increased species competition

0 1 2 3 4 5-0.02

-0.01

0

0.01

0.02

0.03

After habitat loss

Before habitat loss

Male Size Rank

Ag-gres-sion

largest smallest

Loss of habitat increased species competition

Competition: The Game

Species A vs. Species B Environment 1

• Species A = Red-filtered vision • Species B = Blue-filtered vision species• Multiple types of available food items• 60 seconds to collect as many food items as you can• You need 5 units of food to survive until tomorrow• You must

– Pick up one food item at a time and return it to your stomach (cup)– Walk carefully– Not physically interfere with other organisms

Competition: The Game

• Use your worksheet to record food items eaten by each member of your species

Competition: The Game

Species A vs. Species B Environment 2

A disease has drastically reduced the number of one of the prey items.

You must forage for food in this new environment.

Competition: The Game

• Use your worksheet to record food items eaten by each member of your species in Environment 2.

• Graph total # of food items of each color eaten by all members of your species.

• How do results compare between environments? (Groups prepare to report out)

Competition: The Game

• How do results for each species compare?

Competition: The Game

• What other changes to the game environment can you imagine?

• Small groups develop ideas

• Entire group votes on one question to test

• Make predictions

• Test question and interpret results

• Competing takes energy and time

• Poor competitors get less of the resources (food, territory)

• This leads to lower survival and reproduction

Competition is Costly

How can organisms reduce this cost?

Reduce competition by specializing

Eats detritus (dead material on pond bottom)

Eats shrimp that swim in pond

Reduce competition by specializing

Eats invertebrates in the sediment of the lake bottom

Eats plankton that swim in open water of the lake

= Niche differentiation

Competition in Bioenergy Plots

How might competition be important in bioenergy plots?