Species Interactions

Bellringer Mass leaves to find biomass Defend the following statement: Species interactions are the driving

force behind natural selection.

Pop Quiz?? Cycles in Nature

Ecology vocabulary preview: Biotic factors Abiotic Niche (Fundamental and Realized) Competition

EQ: How do species interactions drive changes in organisms?

Predator/Prey Parasitism Commensalism Mutualism Commensalism

Predator-Prey

Parasatism

Parasitism

Mutualism

Commensalism

Competitive Exclusion Principle Tansley (1917) showed (1)

that the presence of absence of a species could be determined by competition with other species; (2) that conditions of the environment (in this case, soil type) affected the outcome of competition; (3) that competition might be felt very broadly at first (i.e., from other vegetation throughout the community); and (4) that the present ecological segregation of species might have resulted from competition in the past.

Bellringer: Explain the

predator-prey model

What is a symbiotic relationship?

Name the three types of symbiotic relations ships and give examples of each

Competition can be a driving force in evolution; this example is know as

character displacement.

of resource partitioning.

                                                 

Competitive Exclusion Principle

2. Gause: used cultures of protozoans to develop the competitive exclusion princple (1934).

two species cannot coexist on the same limiting resource.

Competitive Exclusion two species

competing for the same resources cannot stably

coexist Connell

(1961)

Limiting Resource/Factor

Resource Partitioning Charles Darwin noticed that competition

is most intense between similar species that require the same resources.

Robert MacArthur studied several species of warblers that foraged in the same tree. A closer look showed that each species hunts for insects in a different part of the tree.

process by which natural selection drives competing species into different patterns of resource use or different niches.

Resource partitioning: process by which natural selection drives competing species into different patterns of resource use or

different niches.

On the next slide, have students analyze the graph and then work with a partner to draw some conclusions.

Discuss the student’s ideas in class.

Competition can be a driving force in evolution; this example is know as

character displacement.

of resource partitioning.

                                                 

Coevolution Two or more species living in a close

relationship may cause each other to evolve as a response to each others changes.

My example: As a prey item evolves better camouflage, the predator evolves keener eye site.

Can you come up with an example?

Coevolution at its best!

                     Here you can see two Heliconius eggs

that have been layed on a passionflower leaf.

                             Here you can see the leaf on one

passionflower species which has evolved to "fake eggs" (nectaries) to make the moth think that the leaf is already occupied. (Moths will not lay their eggs on occupied leaves because newly hatched lavae will often eat other eggs on leaves before eating the leaf)

 

Begin Predator-Prey Model

Adaptations Mimicry Toxins Aposomatic coloration Plants: Physical defenese, chemical

defenses Secondary compounds – nicotine,

strychnine, poison ivey

Batesian Mimicry

Coevolution at its best!

This tropical ant of the species Cephalotes atratus is infected with a parasitic roundworm that makes its bulbous rear end, called a gaster, look like a juicy red berry. Researchers believe the parasites transform the gasters to trick foraging birds into eating the ants. Birds poop out parasite eggs, allowing the worms to spread to new ant colonies.

Ecological Succession Primary Succession Secondary Succession Pioneer Species Climax Community

Ecological Succession

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Primary or Secondary

Bellringer (Begins on pg 436) How does the greenhouse effect occur? What is biodiversity? Compare species richness and species evenness.

Compare species diversity and genetic diversity.

Calculate the species richness and species evenness for each island. Island X has 50 individuals of species A, 200 of species B and 2000 of species C. Island Y has 300 of species A, 300 of species B and 500 of 200 of species C and 500 of species D.

Which island has the greatest biodiversity?

Environmental Issues Pollution – smog Ozone thinning Global Warming Acide Rain Biological magnification Extinction Keystone species Sustainability Environmental Footprint