Primary Succession Succession Time Rocks Rocks with moss Grasses Shrubs Small Trees Big Trees Secondary Succession Sparse Grass

Discuss with your group… 1. Together, come up with a definition for succession by looking at the pictures. 2.What is the difference between Primary and Secondary succession?

2.1 Section Objectives – page 35 describe how events and processes that occur during ecological succession can change populations and species diversity. Today’s Objective: Can be found in the book: Pg

If grass were no longer cut on a lawn, what would it look like in a year? Five years? In 90 years? Ecologists can predict the changes that will take place over time in an area….like evolution of an environment

Section 3.1 Summary – pages Ecologists refer to the natural changes that take place in an ecosystem over time as succession. Succession occurs in predictable stages At each stage, different species of plants and animals may be present. Succession: Changes over Time

Section 3.1 Summary – pages As succession progresses, new organisms move in. Others may die out or move out. There are two types of succession— primary secondary. Succession: Changes over Time

Section 3.1 Summary – pages The colonization of organisms in a completely barren land is called primary succession. Primary succession takes place on land where there are no living organisms.

Section 3.1 Summary – pages The first species to take hold in an area like this are called pioneer species. PRIMARY SUCCESSION

Section 3.1 Summary – pages As these first organisms die, more soil builds- and it has more and more nutrients in it. ­ Exposed rock Primary succession PRIMARY SUCCESSION As soil builds, bigger plants will grow, bringing in herbivores and eventually carnivores

Section 3.1 Summary – pages Secondary succession is the sequence of changes that takes place after an existing community is severely disrupted in some way. Secondary succession, however, occurs in areas that still have land containing nutrients in the soil.- Not completely starting from scratch, like primary. SECONDARY SUCCESSION

Section 3.1 Summary – pages A stable, mature community that undergoes little or no change in species is a climax community.

In an evolving ecosystem, populations will continue to grow until they reach their carrying capacity. This is the maximum amount of organisms that can survive in an ecosystem –It is determined by the amount of resources available, such as: Habitat Water Food No population can live beyond the environment’s carrying capacity for very long.

● The “J” shape shows growth at a constant rate (exponential growth). ● When the “J” becomes an “S” shape…it means the population has reached carrying capacity.

Section 3.1 Summary – pages Life In an Ecosystem Conditions in one part of the world are suitable for supporting certain forms of life, but not others.

The ability of an organism to withstand fluctuations in biotic and abiotic environmental factors is known as tolerance. Ranges in Tolerance For example, some crops may survive a long drought period- They may not produce as well, but they’re able survive. This makes me think of “Children of the Corn” – shut up, it was scary when I was little…..

Common Limiting Factors Sunlight Climate Atmospheric gases Temperature Water Nutrients/Food Fire Soil chemistry Amount of Space Other organisms A limiting factor is any biotic or abiotic factor that can affect the existence of an organism.

Section 3.1 Summary – pages Factors that limit one population in a community may also have an indirect effect on another population. Limiting Factors For instance, what if a drought caused grass to reduce the number of seeds it produces… What would happen to the mice that feed on those seeds? What would happen to the hawks that feed on those mice?

What are some limiting factors for this little guy? And why? If it’s too dry, Mr. Frog can’t breathe…and if no water around, can’t reproduce.