Principles of Ecology Chapter 2 Section 1

Standard 4.1 Standard 4: The interdependence of Organisms - Interdependence of organisms in an environment includes the interrelationships and interactions between and among organisms. Substandard 1: Organisms both cooperate and compete in ecosystems (symbiotic relationships)

Ecology Def: the study of interactions that take place between organisms and their environment. Where are living things found? – Biosphere: the portion of Earth that supports living things

Ecology Living things are affected by both the physical (nonliving environment) and by other living things. Ecologists study how organisms survive and reproduce under different physical and biological conditions in Earth’s biosphere.

The Non-living Environment Abiotic factors: the nonliving parts of an organism's environment. – Examples: air currents, temperature, moisture, light, soil, water salinity, drought

Abiotic factors affect organisms What is the factor influencing photosynthesis? How much glucose is being produced at 20 degrees? At what temperature is glucose production greatest? What happens to the formation of glucose after the temperature reaches 30?

The Living Environment Biotic factors: all the living organisms that inhabit an environment. – Examples?

Levels of Organization

Section 2.1 Summary – pages Biotic and abiotic factors form ecosystems Terrestial ecosystems are those located on land. Table 2.1 Examples of Ecosystems Terrestrial Ecosystems Forest Old farm field Meadow Yard Garden plot Empty lot Compost heap Volcano site Rotting log Aquatic Ecosystems Freshwater Pond Lake Stream Estuary Salt water (marine) Ocean Estuary Aquarium Other Sites for Ecosystems Human body Skin Intestine Mouth Buildings Mold in walls, floors, or basement Ventilation systems Bathrooms Food Any moldy food Refrigerator Aquatic ecosystems occur in both fresh- and saltwater forms.

Mini-Lab 2.1: Salt Tolerance of Seeds (Page 36 in textbook) Salinity is the amount of salt dissolved in water- a nonliving factor. How do you think salinity might affect the germination of certain seeds? – Create a hypothesis: If the ___________ increases than the rate of ________ will __________. – Identify control, dependent and independent variables.

Section 2.1 Summary – pages Organisms in Ecosystems A habitat is the place where an organism lives out its life.

Section 2.1 Summary – pages Organisms in Ecosystems Habitats can change, and even disappear. Habitats can change due to both natural and human causes.

Section 2.1 Summary – pages Niche Although several species may share a habitat, the food, shelter, and other essential resources of that habitat are often used in different ways. A niche is the role or position a species has in its environment—how it meets its specific needs for food and shelter, how and where it survives, and where it reproduces in its environment. It is thought that two species can’t exist for long in the same community if their niches are the same.

Section 2.1 Summary – pages A niche is the role or position a species has in its environment It is thought that two species can’t exist for long in the same community if their niches are the same.

P. means Parmecium which is a one-celled protist that lives in ponds and other freshwater bodies of water. Competitive Exclusion

Graphs showing competition between two species of Paramecium. Since each population alone prospers (FIRST two graphs), when they are in a competition situation one species will win, the other will lose (THIS graph). Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates ( and WH Freeman ( used with permission..

Survival Relationships Symbiosis is a close ecological relationship between two or more different species. Three types: m

Section 2.1 Summary – pages Both benefit Oxpeckers and zebra/rhinoceros Mutualism

Section 2.1 Summary – pages one species benefits and the other species is neither harmed nor benefited. Commensalism

Section 2.1 Summary – pages Parasitism Some interactions are harmful to one species, yet beneficial to another. Parasites have evolved in such a way that they harm, but usually do not kill the host species.

Type of Relationship? WHY? Carcass eaters that follow hunting animals Cattle egrets and livestock Fleas/ticks on an animal Mosquitoes and humans Bird and a tree (that it lives in) C. difficile (bacteria in intestine) and humans Bee and flower