Pioneer Organisms and Climax Community in Ecological Succession

2. Pioneer Organisms • Some of the FIRST species that come in and repopulate an area that is either a Primary Succession spot or has suffered damage and is experiencing Secondary Succession. • 1. Mosses/Lichen • 2. Grasses • 3. Small shrubs • Climax Community / Climax Organisms • These are species of plants that take a long time to get established, but tend to provide a sense of permanence to an environment. • -Often referred to as MATURE or OLD-GROWTH • 1. Redwood Trees • 2. Douglas Fir • 3. White Oak

3. Ecological Succession • The observed process of change in the species structure of an ecological community over time. • Gravitropism / Geotropism • Turning or growth movement by a plant or fungus in response to gravity. • It is essentially the method by which plant roots go downward, while their stems grow upward. • Photosynthesis is the chemical process which changes • chemicals and nutrients into food. • Any species that uses photosynthesis to produce food is called a phototroph.

4. Primary Succession • Succession that begins in new habitats, uninfluenced by pre-existing communities of plants. • In other words, this is Succession that occurs if we start in a desert or other very desolate area. • Secondary Succession • Succession that follows disruption of a pre-existing community. • Disruption includes: • 1. Forest Fire • 2. Floods • 3. Tornadoes or other Weather events • 4. Human Logging and Agriculture

5. Petal- Modified leaves that make up the outermost ring of flower parts and protect the bud. They also attract insects. • Sepal-small leaves under the flower. • Stamen-The male reproductive structure of flowers. • Pistil-The female reproductive structure of flowers.

6. Filament-A thin stalk of the stamen that holds the anther. • Anther-The part of the stamen that contains pollen (sperm). • Pollen-A fine dust that contains the sperm of seed-producing plants. • Stigma-The tip of the pistil that receives the pollen during fertilization.

7. Style-The narrow elongated tube part of the pistil between the ovary and the stigma. • Ovary-The rounded base of a pistil that contains one or more ovules. The female reproductive organ. • Ovule-reproductive cell which will become the seed when fertilized by pollen. • Peduncle (stem)-A slender or elongated structure that supports a plant or fungus.

8. For photosynthesis to occur a plant needs: • Water • Chemical Energy from Sunlight • Chlorophyll • Carbon Dioxide • Photosynthesis yields (produces): Oxygen & Glucose • Formula for photosynthesis • 6CO2+6H2O------> C6H12O6+6O2

9. Glucose • Sugar is chemically called Glucose, and produces energy. Glucose is a common substance in nearly every form of life that produces energy. All of the food we eat is converted to glucose. Plants use glucose as the primary part of the food that is stored. The oxygen is released into the air since the plant no longer needs it. • Respiration • The opposite reaction to photosynthesis. Respiration occurs once an animal or human eats the food that contains glucose. • Formula for respiration: C6H12O6+6O2 ---> 6CO2+6H2O

10. Turgor Pressure • Pushes the plasma membraneagainst the cell wall of plant, bacteria, and fungi cells as well as those protist cells which have cell walls. • When plants begin to wilt, it is said that they are experiencing LOW turgor pressure • Once plants fill their vacuoles with water, the cells are now experiencing HIGH turgor pressure. • When a plant is wilting, the force is greatest at the CELL WALL. When a plant is wilting, the force is weakest at the VACUOLE.

11. Ecological Succession