H O M E S C H O O L W E B A C T I V I T YM A R C H 2 0 1 2

POPULATION DYNAMICSHOUSTON ZOO

WHAT IS POPULATION DYNAMICS?

•The study of changes in a population(s) within an ecosystem

LET’S BREAK IT DOWN…

• In order to understand populations within an ecosystem, we need to first understand how an ecosystem is organized!

ECOSYSTEM

• What is an ecosystem?• The interactions and relationships between

biotic factors (living things) and abiotic factors (non-living things) within a location (forest, pond, city, cave, etc.)• These biotic and abiotic factors form a

functioning unit• The two major forces that link all the biotic

and abiotic factors in an ecosystem are:• The flow of energy through an ecosystem • Cycling of nutrients within an ecosystem

ORGANIZATION OF ECOSYSTEMS

• Living organisms are in groups ranging from specific to broad :• Individuals• Population• Community • Ecosystem

INDIVIDUAL

• Biotic; one living thing (cat, oak tree, human, etc.)

POPULATION

• Biotic; a group of individuals of the same species who inhabit a location (i.e. a pride of lions in a wildlife preserve, packs of wolves who live in Yellowstone, etc.)

COMMUNITY

• Biotic; a group of different populations (of different species) who inhabit a location (i.e. wolves, bison, deer, and bear within Yellowstone)

*Photos courtesy of U.S. Fish and Wildlife Service

ECOSYSTEM

• Biotic and abiotic; the interaction between the community and the abiotic factors within a certain location (i.e. fish, rays and sea turtles interacting with rocks, water and sand within a coral reef)

*Photo courtesy of U.S. Fish and Wildlife Service

Individual ↓

Population ↓

Community↓

Ecosystem

CHANGING THE POPULATION DYNAMICS

Imagine yourself in Yellowstone National Park…• What would happen if you removed all of the predator

species (mountain lions, bears, wolves)?• What would happen if you removed all of the prey

species (deer, moose, rabbits)?

• If the balance of predators or prey (or both) is disturbed in an ecosystem, the ecosystem becomes unhealthy.

• What can affect ecosystem imbalance?• Natural disasters (earthquakes, hurricanes, tornadoes,

blizzards, mud slides, etc.)• Human interaction• Natural resource depletion

MAINTAINING ECOSYSTEM BALANCE

• Conservationists work to maintain ecosystem balance, and they can do it in several ways:• Studying/researching declining animal populations• Studying/researching declining plant populations• Natural resource management• Natural disaster recovery efforts• Educating people who live near animal populations about those

species’ and the importance and benefits of biodiversity• Working alongside communities where endangered species live

to improve their standard of living

• Successful conservationists don’t just work with one animal. To be successful, they must consider all aspects of an ecosystem (both biotic and abiotic) to save endangered animals, plants, or both.