- Slides: 54
Ecology and our World Ecology The study of interactions between living things and their environment Levels in Ecology 1. Individual A single member of a species 2. Population A group of individuals of a species. 3. Community Several species in an area. 4. Ecosystem Living and nonliving things in an area Group of ecosystems 5. Biome 6. Biosphere All the biomes
How do organisms interact? Producers - organisms that produce their own energy, and are food for other organisms. They are also called autotrophs Consumers - organisms that have to eat other organisms for their energy They are also called heterotrophs
Consumers come in a wide variety Herbivores - Organisms that eat only plant material. Carnivores - Organisms that eat only other animals. Omnivores - Organisms that eat both plant and animal. Detrivores - Organisms that eat “dead matter” Decomposers - Organisms that break down organic matter
Who eats who? Food Chain - a series of steps showing which organisms eat which. (transfer energy) Food Web - a chart linking all food webs in a particular area
Feeding Relationships • A food chain shows a simple feeding relationship. Sun → • All food chains start with the sun
Feeding Relationships • A food chain shows a simple feeding relationship. Sun → grass →
Feeding Relationships • A food chain shows a simple feeding relationship. Sun → grass → rabbit →
Feeding Relationships • A food chain shows a simple feeding relationship. Sun → grass → rabbit → fox
All food chains start with ENERGY from the sun
carbon dioxide from the air water from the roots food transported to the rest of the plant energy from sunlight (or light)
Photosynthesis carbon dioxide from the air water from the roots food transported to the rest of the plant energy from sunlight (or light)
Because plants produce their own food, they are called ‘Producers’
The energy is then passed on to animals when they eat the plant.
Animals of all shapes…
Because these animals are the first to take the food energy from the plants, They are called primary consumers
Some of these primary consumers have predators. Other animals that feed on them
Aphids are eaten by….
Animals that eat primary consumers are called secondary consumers
• So far this is a straightforward food chain • Sun → leaves → aphid → ladybugs But in reality it is more complicated than that
This bird eats ladybugs and aphids
This bird eats smaller birds, mice, and rabbits
Mice and rabbits have other predators
What will eat the frog? What do you think the frog eats?
Sometimes it’s not entirely clear who eats who!
We can show what goes on with the help of a Food Web
What would happen if a disease killed off many of the hawks?
There will be nothing to eat the snakes, so their numbers will increase.
All the frogs get eaten
No frogs. More crickets
Most of the cattail gets eaten by the crickets
Now the crickets don’t have enough food so their numbers go down
. . and so on. Numbers of each species have an effect on the numbers of the other species in the web.
Handout is due at the beginning of class tomorrow
Warm-up (3/28) ■ What is the difference between a food web and a food chain?
Successiona series of changes in a community in which new populations of organisms gradually replace existing ones
Primary successioncolonization of new sites by communities of organisms – takes place on bare rock
Primary succession. New bare rock comes from 2 sources: 1. volcanic lava flow cools and forms rock
Primary succession. New bare rock comes from 2 sources: 2. Glaciers retreat and expose rock
Pioneer organismsthe first organisms to colonize a new site Ex: lichens are the first to colonize lava rocks
Primary Succession. Rock
Climax communitya stable, mature community that undergoes little or no succession
Climax community. Ex: In most of Virginia, the climax community would be a deciduous oak–hickory forest
Secondary successionsequence of community changes that takes place when a community is disrupted by natural disaster or human actions – takes place on existing soil
Secondary succession. Ex: A fire levels portions of a forest
Secondary succession. Ex: A farmer plows his field