* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Changes in Ecosystems
Survey
Document related concepts
Habitat conservation wikipedia , lookup
Crop rotation wikipedia , lookup
Theoretical ecology wikipedia , lookup
Ecological fitting wikipedia , lookup
No-till farming wikipedia , lookup
Regenerative agriculture wikipedia , lookup
Biological Dynamics of Forest Fragments Project wikipedia , lookup
Renewable resource wikipedia , lookup
Sustainable agriculture wikipedia , lookup
Perovskia atriplicifolia wikipedia , lookup
Transcript
Changes in Ecosystems: Ecological Succession 1.05 Determine the interaction of organisms within an ecosystem. Ecological Succession • Ecological Succession is the natural, gradual changes in the types of species that live in an area; can be primary or secondary • The gradual replacement of one plant community by another through natural processes over time Primary Succession • Primary succession is the beginning of a community where few, if any, living things exist, or where earlier communities were wiped out. • Begins in a place without any soil o Sides of volcanoes o Landslides o Flooding • Starts with the arrival of living things such as lichens that do not need soil to survive • Called PIONEER SPECIES – The first species living in an otherwise lifeless area. • • Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil A pioneer community is the first community thriving in a once lifeless area. • Simple plants like mosses and ferns can grow in the new soil • • The simple plants die, adding more organic material The soil layer thickens, and grasses, wildflowers, and other plants begin to take over These plants die, and they add more nutrients to the soil Shrubs and tress can survive now Insects, small birds, and mammals have begun to move in What was once bare rock now supports a variety of life • • • • Secondary Succession • Begins in a place that already has soil and was once the home of living organisms • Occurs faster and has different pioneer species than primary succession • Example: after forest fires Climax Community • A stable group of plants and animals that is the end result or final stage of the succession process • Does not always mean big trees – Grasses in prairies – Cacti in deserts Primary vs. Secondary Primary • No soil • Pioneer species • Weathering & decomposition • Humus and sand increase over time • End = climax community Secondary • Soil already exists • Seeds have suitable soil conditions. • Occurs much faster • Climax community. Key concepts: • Pioneer species—first species to begin a succession. • Climax community—the final stage in a succession. Ecological succession — Change of environment involving a series of species replacements in a community. Primary succession — occurs where there is no soil, e.g. after a volcanic eruption or a glacial retreat • “pioneer organisms” • Simple plants first – no or shallow roots. • Gradual influx of more complicated and larger plants as the habitat changes. • Ends with a “climax community” – ecosystem stays constant, provided there are no changes in abiotic influences. Secondary succession — begins in an area where soil is already present, (e.g. a once cultivated field or after a forest fire.) Old field succession: grasses + weedsÆ taller grasses + golden rodÆ small trees (cherries, dogwood, sumac) Æ mature climax forest (oak, beech-maple, hickory)