Ecosystems and Ecology Ecological

Ecosystems and Ecology

Ecological Succession

• Definition: The natural progression of communities/ecosystems over time, leading to a climax community.

• Types:

  • Primary Succession: Occurs in areas devoid of life, e.g., after volcanic eruptions or glacial retreats.

  • Secondary Succession: Occurs in areas where an ecosystem was disrupted but soil remains, e.g., after wildfires or hurricanes.

Ecotones

• Definition: The zones of transition between two adjacent ecosystems.

Organization of Nature (From Least to Most Complex)

1. Chemical: Atoms and molecules essential for life.

2. Cellular: Basic unit of life.

3. Tissues: Groups of similar cells performing a function.

4. Organs: Composed of different tissues, functioning together.

5. Organ Systems: Groups of organs working together.

6. Organism: A single living entity.

7. Population: All members of one species in an area.

8. Community: All populations in a given area.

9. Ecosystem: All living (biotic) and nonliving (abiotic) factors in an area.

10. Biosphere: The portion of Earth where life exists (all ecosystems combined).

Climate and Environmental Factors

• Ocean Currents & Hurricanes:

  • In the northern hemisphere, ocean currents move clockwise, and hurricanes circulate counterclockwise.

• Causes of Wind: Differential heating of the Earth's surface.

• Seasons: Caused by the tilt of the Earth's axis.

• Climate Zones: Exist due to the Earth's spherical shape.

Major Elements & Their Biological Importance

Reproduction & Population Dynamics

Types of Consumers

• Omnivore: Eats both plants and animals.

• Herbivore: Consumes only plants.

• Carnivore: Consumes only animals.

Territory vs. Home Range

• Territory: Defended area within a home range.

• Home Range: Total area an animal normally inhabits.

Types of Population Growth

• Exponential Growth (J-shaped curve): Rapid growth without environmental limits.

• Logistic Growth (S-shaped curve): Growth slows as it reaches carrying capacity.

• Complex Growth: Fluctuations due to environmental factors.

Reproductive Strategies

• Sexual Reproduction: Genetic variation, better adaptation.

• Asexual Reproduction: Fast, no partner required.

Mating Systems

• Promiscuity: Random mating among many males and females.

• Monogamy: One male and one female mate exclusively.

• Polygyny: One male mates with multiple females.

Species Interactions

• Altruism: One organism sacrifices to help another.

• Commensalism: One benefits, the other is unaffected.

• Mutualism: Both organisms benefit.

Energy Flow in Ecosystems

• Producers (Autotrophs): Convert sunlight into energy.

• Consumers (Heterotrophs): Obtain energy by consuming other organisms.

• Decomposers: Break down dead organisms, recycling nutrients.

• Only ~10% of energy is transferred between trophic levels.

Additional Topics to Review

• R-strategists vs. K-strategists:

  • R-strategists: Many offspring, little parental care, short lifespan.

  • K-strategists: Few offspring, high parental care, long lifespan.

• Specialists vs. Generalists:

  • Specialists: Thrive in specific environments (e.g., koalas).

  • Generalists: Adapt to various environments (e.g., raccoons).

Niche: The role an organism plays in its ecosystem.