1. Ecosystem Balance
Ch. 6

2. Relationship in Ecosystem
Energy is cycled in ecosystems……
Predator: hunts other organisms
Prey: the hunted
Praying mantis
Increases in a prey generally lead to increase in predator populations

3. Population Changes

5. Parasitism
One organism feeds on tissues/body fluids of another (the host)
Parasite
Harmful to hosts, but usually don’t kill
Live on the body of host
Density dependent
Population size of parasite depends on population of host

6. Symbiosis Two species live closely together Examples
Parasitism: one species benefits, other is harmed
Aphids and plants
Commensalism: benefits one species and doesn’t really affect the other
Barnacles and whales
Mutualism: both species benefit
Plants and insects that pollinate them

7. Use the information below to answer the following.
Aphids are insects that feed on fluids from the stems of plants. After the aphids ingest the plant fluids, they excrete a liquid called honeydew.
Ladybugs eat aphids, which are a source of protein for the ladybugs. Which of these terms best describes the relationship between the ladybugs and the aphids?
A. mutualism
b. parasite–host
C. predator–prey
D. commensalism
Praying mantis

8. A few examples of parasites are tapeworms, fleas, and barnacles
A few examples of parasites are tapeworms, fleas, and barnacles. Tapeworms are segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans. They get food by eating the host's partly digested food, depriving the host of nutrients. Fleas harm their hosts, such as dogs, by biting their skin, sucking their blood, and causing them to itch. The fleas, in turn, get food and a warm home. Barnacles, which live on the bodies of whales, do not seriously harm their hosts, but they do itch and are annoying.
Some parasitic animals attack plants. Aphids are insects that eat the sap from the plants on which they live. Parasitic plants and fungi can attack animals. A fungus causes lumpy jaw, a disease that injures the jaws of cattle and hogs. There are also parasitic plants and fungi that attack other plants and fungi. A parasitic fungus causes wheat rust and the downy mildew fungus attacks fruit and vegetables. Some scientists say that one-celled bacteria and viruses that live in animals and harm them, such as those that cause the common cold, are parasites as well. However, they are still considered different from other parasites. Many types of parasites carry and transmit disease. Lyme disease is trasmitted by deer ticks.

9. Ecological Succession
What happens to a lawn or garden overtime if it is not cared for?

10. Ecological Succession
Succession: changes overtime to a landscape
Types:
Primary
Secondary
Aquatic
Island

11. Primary Succession Sequence of organisms coming to a lifeless habitat
First: colonization by new organism
Pioneer Community: 1st to colonize
On Land: rocks are colonized by lichens
Lichens: fungus and an alga
Secrete acids to break down rock form organic material
Help to form soil
Second: formation of soil
Third: grasses and small plants (block light so no more lichen)
Fourth: shallow root trees
Fifth: deep root trees
Climax Community: undergoes no more growth/change (stable)

12. Secondary Succession
Occurs in area after a disturbance eliminates most organisms, but doesn’t destroy soil
Usually after human disturbances (fires)
Resembles later stages of primary succession
Will also eventually result in climax community
Example:grasslands

13. Aquatic Succession Starts as a nutrient –poor lake
Supports few organisms
Overtime water plants begin to grow near the shore
Becomes more nutrient-rich
lake fills with sediment and becomes a marsh
Land plants move in; ultimately turns into a forest

14. Island Succession New islands can form after volcanoes erupt
New organisms’ ancestors came there by water, wind, or hitching a ride
Majority have large bird populations
Offspring evolves to fill several niches
Usually is little competition for food/resources because few organisms
New species tend to form because mates may be difficult to come by and available niches
Ecological succession

15. Stability in the Ecosystem
Stability: measure of how easily an ecosystem is affected by a disturbance and how quickly it returns to it original condition after the disturbance.
Equilibrium: disrupted ecosystem returns to a state of balance

16. Disruptions
Major disruptions can cause drastic changes-even complete destruction of the ecosystem
A new ecosystem will eventually evolve
Dinosaurs
Were believed to go extinct due to the impact of a large object from space
After the dinos were gone, many different kinds of mammals evolved

17. Chaos Theory
Chaos Theory: ecosystems may be sensitive to very small changes
Now: species are becoming extinct at faster rates
Reasons:
Human population growth
Habitat destruction
Introduction of foreign species
Pollution of fresh water

18. Biomes
Biome: a major type of ecosystem with distinctive temperature, rainfall, and organisms
Land (terrestrial)
amount of precipitation and temperature
Water (aquatic)
Water depth, nutrients, nearness to land
Biomass: total mass of organic material

19. Figure 9k-1:
Figure 9k-1: Distribution of the Earth's eight major terrestrial biomes. Legend is below. (Adapted from: H.J. de Blij and P.O. Miller Physical Geography of the Global Environment. John Wiley, New

20. Land Biomes Desert Tundra Coniferous forest Deciduous forest
Rain forest
Savanna
Temperate Woodland and Shrubland
Steppe and Prairie
Very little water; small amt biomass
Forests: contain 75% Earth’s biomass

21. Rain Forests Cover 6% surface, but contains 50% biomass Most diverse
Tropical Dry Forest: rainy season followed by dry season

22. Temperate Woodland and Shrubland
Precipitation varies
Located only 5 areas-all on shorelines
Contain chaparral: low plants that contain flammable oils
Catch fire easily  some plants have seeds that can only germinate after being exposed to fire