Lecture # 5 SCIENCE 1 ASSOCIATE DEGREE IN EDUCATION POPULATIONS AND ECOSYSTEMS Continue…..

FROM SIMPLE TO COMPLEX Follow Up on last week In last week, Students explored: 1.Their own plot of land, a tiny section of an ecosystem. They should have catalogued the organisms that live in it and the physical environment that provides the resources organisms need to survive. 2.These resources include water; soil; the appropriate temperature; gases, such as carbon dioxide and oxygen; organic and inorganic nutrients; sunlight; and shelter. They should have observed that organisms in an ecosystem may cooperate or compete for these resources and that these interactions can vary. 3.They ended the week by creating a concept map of their sample ecosystem and hypothesized how it might react to change.

FROM SIMPLE TO COMPLEX continue…….. This week, Students further explore the complex interdependence and interactions of organisms in an ecosystem and how ecosystems adapt to changes.

ACTIVITY # 1 Students first explain their understandings of the interrelationships in ecosystems and then explore the concept of an ecological niche. They describe how niches help increase diversity within an ecosystem and maximize the number of populations that can live in that ecosystem.

ACTIVITY # 1 continue Students then explore populations by examining the factors that cause natural populations of organisms to increase or decrease in size. To describe the dynamics of population growth, they analyze complex patterns of population size. Then they determine how populations change over time. By analyzing data and creating and interpreting graphs, they understand the importance of population patterns and use this knowledge to predict future trends. By using graphs of population data, they can calculate the carrying capacity for a population in an ecosystem.

ACTIVITY # 1 continue They analyze the effects of mutual relationships, such as symbiosis, parasitism, and commensalism by interpreting data and graphs and carrying out simulations. By the end of the week, Students understand that the population size an ecosystem can support depends on the resources available. They also understand that certain factors limit the growth of populations.

ACTIVITY # 1 continue The analysis of population trends leads to a study of change in ecosystems and dynamic equilibrium. Students learn that ecosystems are dynamic, not static, and that populations of organisms and their physical environment adjust constantly. They explore the effects that changes have on populations. They then determine factors that add to an ecosystem’s stability, particularly how feedback loops keep an ecosystem in equilibrium.

ACTIVITY # 1 continue As a conclusion to this unit, Students investigate the effects of human activities (such as pollution, habitat destruction, or urbanization). They examine naturally occurring changes to ecosystems (such as natural disaster, disease, population increase, or depletion of food) and the short-term and long-term results of those changes.

Extension As an extension, you could provide Students with the following ‘long-term’ research project: what happens to an ecosystem when a major event—such as a raging fire, volcano, or typhoon—destroys large parts of the ecosystem?