Unit 2 – Ecosystems and Population Change Chapter 3 deals with Ecosystems and Diversity. During this chapter we will be going on a field trip to study some of the populations in our area. After that, we will move on to Chapter 4, which deals with the Mechanisms of Population change. Discuss the information on page 77 regarding the mountain pine beetle. Give students 10 minutes to complete the launch lab (may extend to 15 minutes if the students are working hard). 3.1 – Individuals, Populations, and Communities in Ecosystems Mr. Standring

Learning Objectives What is an ecosystem? What are populations and communities? How do these fit into ecosystems? Mr. Standring

The Parts of an Ecosystem An ecosystem is made up of many parts. Ecosystems can take up many hectares of land or can be small, such as a tide pool or a rotting log. Abiotic factors include air, water, soil, nutrients, and light. Biotic factors include plants, animals, and micro-organisms. A habitat is where an organism lives. The habitat of the red fox often includes the edges of forests or marshlands. (c) McGraw Hill Ryerson 2007

Ecotones Ecotones A transition area between ecosystems Mr. Standring

Abiotic Interactions in Ecosystems The abiotic components are what allow the biotic components to survive in an ecosystem. Abiotic factors include: oxygen, water, nutrients light and soil. Mr. Standring See pages 37 - 38

Abiotic factors: Oxygen Oxygen is produced by the green plants and certain micro-organisms and is used by animals and most other micro-organisms. Mr. Standring

Abiotic factors: Water Water is necessary for all life. Mr. Standring

Abiotic factors: Nutrients Nutrients often enter the food chain with plants and are very important for growth. Mr. Standring

Abiotic factors: Light Light is required for photosynthesis, which is the process in plants that converts and stores the Sun’s energy in the form of starches and carbohydrates. Mr. Standring

Abiotic factors: Soil Soil not only contains water and nutrients but also is home to many plants and animals. Earthworms in soil Mr. Standring

Individual Organisms How does the environment affect Behavior? Physical features (Morphology)? Helps to explain why some organisms are only present in certain areas What physical features (morphology) allows this cactus to grow in some environments but not others? Mr. Standring

Populations Species Population Organisms that can breed with each other and produce fertile offspring Population A group of individuals of the same species living in a specific area at the same time Population Ecologists study the changes in populations over time (increase, decrease, stay the same), and what factors determine the relative numbers of males and females or young and old individuals. Mr. Standring

Communities Community Interactions affecting communities: All individuals in all of the interacting populations in a given area Interactions affecting communities: Competition Predator/prey relationships Symbiotic Relationships Abiotic factors Community ecologists study the interactions among the members of different populations Mr. Standring

Symbiotic relationships Symbiotic relationships are the interactions between members of two different species that live together in a close association. Mr. Standring

Commensalism Commensalism – one species benefits, one is not affected Example: Clownfish living in a sea anemone Mr. Standring

Parasitism Parasitism – one species benefits, the other is harmed Example: hookworm living in dogs A mosquito drinking human blood A lamprey eel living off a fish Mr. Standring

Mutualism Mutualism – both species benefit Example: a bee gathering nectar from a flower Birds eating parasites off a rhino. Mr. Standring

Niches and Competition A niche refers to the role an organism has within an ecosystem, physically, chemically and biologically. Competition occurs when a resource is needed by two or more individuals. Competition usually means resources are limited. This limits the size and health of that individual and perhaps that population. Coyotes compete over habitat or food sources. Mr. Standring

Predation Predation is the relationship between the “eaters” and the “eaten”. Predators have adaptations to help them catch their prey. Prey have adaptations to help avoid predators. Examples of adaptations include spines and shells, camouflage and mimicry. The numbers of predators and prey influence each other. Mr. Standring

Biodiversity in Ecosystems Biodiversity refers to the variety and number of different individuals and species in an ecosystem. Healthy ecosystems generally have high biodiversity. Most biodiversity losses occur from the loss of habitat. Wetlands provide habitats. Mr. Standring

The impact of Humans on Ecosystems Humans often have a negative impact on biodiversity. Many efforts are now made to lessen this impact in order to maintain biodiversity. Ecological management programs try to balance human progress with maintaining biodiversity. Mr. Standring

Environments Change Over Time Abiotic factors Biotic Factors Populations/Communities Succession Here are two places where succession occurs. In the salt marsh, new silt is deposited through tidal action, providing great substrate for some types of hardy plants. These grasses thrive for a few years, and eventually completely cover the new land. After the grasses change the soil, other new plants can begin to grow. This trend continues with increasingly larger plants until trees are able to grow. (as seen on the other side of this body of water). The same thing happens in a forest. After a fire, meadow grasses begin to grow. Next come shrubs and other low plants, and eventually trees can begin to take root. With each different type of plant, the soil, light, and wind conditions change, making the environment more hospitable for the new life forms, and less hospitable for the old. Mr. Standring

Primary Succession Mr. Standring

Earth’s Biosphere Biosphere All of the ecosystems and their interactions Atmosphere, Lithosphere, Hydrosphere Each species has its own niche in the biosphere They live in specific places and are well suited to survive in these areas Assignment: After checking out what sites are possible field trip sites, tell the students where we might go and have them complete Thought Lab 3.1 (Planning for your Field Study) Assign Section 3.1 Review, page 84, #1-8 Assign Case Study (Nelson) Page 88 – Natural and Artificial Ecosystems (this could possibly be part of an assignment for the substitute when I am at the conference) Mr. Standring

The Big Picture Mr. Standring