ENVIRONMENTAL SCIENCE

Chapter 4 The Organization of Life4.1 Ecosystems: Everything is

Connected

4.1 Ecosystems: Everything is Connected Objectives

• Distinguish between the biotic and abiotic factors in an ecosystem.

• Describe how a population differs from a species.

• Explain how habitats are important for organisms.

Defining an Ecosystem

• An ecosystem is all of the organisms living in an area together with their physical environment.

• Coral reefs, rainforests, oak forests, and deserts are all examples of ecosystems.

• Ecosystems have no clear boundaries – they are all interconnected.

The Components of an Ecosystem

• All ecosystems need five basic components in order to survive.

1. Energy2. Mineral nutrients3. Water4. Oxygen5. Living organisms

• The energy source for most ecosystems is the sun.

The Components of an Ecosystem

• An ecosystem is made up of both living and nonliving things.– Biotic factors are the living (and once living)

components of an ecosystem including all of the plants, animals, dead organisms and their parts, and waste products

– Abiotic factors are the nonliving parts of an ecosystem which include water, air, rocks and soil, light, and temperature

The Components of an Ecosystem

• Life can be organized into different levels of ecological organization from most inclusive down to individual.– Biosphere – an inclusive term for all of the life on Earth– Ecosystem – all of the organisms in a given area along

with the physical factors in the area– Community – a group of various species that live in the

same place and interact with one another– Species – a group of organisms that are closely related

and can mate to produce fertile offspring– Population – all the members of the same species that

live in a given area and time– Organism – an individual living thing

The Components of an Ecosystem

• Every organism is a member of a species.– For example, a human is a member of the species

Homo sapiens

• If members of a given species are separated, they may never interact, thus forming more than one population of a given species.

• All living things in an ecosystem belong to one or more communities.

• The plants present often determine what other organisms can live in a certain area.

Habitat• A habitat is the specific place that an organism lives

kind of like our address to humans.– For example, a habitat could be as specific as a pool area

or ripples in a stream or as broad as a desert• Every habitat has specific characteristics that meet

the needs of the organism which lives there.• If the factors that make the habitat suitable for

certain species change, then the nature of the habitat and the organisms that it can support changes.

• Animals need specific habitats in order to survive.• If habitat change is so rapid that species cannot

adapt, then extinction may be the result.

Habitat• The Red Hills Salamander (Phaeognathus

hubrichti) is a large, terrestrial salamander discovered in 1960.

• This salamander is confined to two geologic formations (Tallahatta and Hatchetigbee) in the Red Hills of Alabama.

• It’s habitat is burrows on the slopes of shaded mesic ravines with much hardwood vegetation.

• It is nocturnal and feeds primarily on insects and spiders.

References• Coral Reef Florida Keys -

http://www.photolib.noaa.gov/reef/reef2559.htm

• El Yunque Puerto Rico - http://www.elyunque.com/about.html

• Jaguar - http://www.nwf.org/internationalwildlife/bolivia.html

• Fungus - http://nhs.needham.k12.ma.us/cur/Bio96_97/P5/rainf/T_Rain_Forest.html

References• Wildebeest -

http://www.worldwander.com/southafrica • Wildebeest Herd -

http://peace.saumag.edu/faculty/Kardas/Courses/C&P/Homing_and_Migration.html

• Serengeti Community - http://www.africanluxuryholidays.net/tanzania-serengeti.htm

• Biosphere Concentration - http://oceancolor.gsfc.nasa.gov/SeaWiFS/BACKGROUND/Gallery

References• Red Hills Salamander Distribution

- http://www.pwrc.usgs.gov/ARMIatlas/species.cfm?recordID=173725

• Red Hills Salamander - http://www.forestry.state.al.us/publication/TF_publications/endangered/red_hills_salamander.htm