1. Miss Hillemann Biology I Neshaminy High School
Ecology
Miss Hillemann
Biology I
Neshaminy High School

2. Ecology
Study of interactions among organisms and between organisms and their environment.
Biotic factors: prokaryotes, protists, fungi, plants, and animals
Abiotic factors: nonliving physical and chemical conditions

3. Biotic & Abiotic Factors at 5 Levels
Organisms: smallest unit of ecological study. Ex: sweetlip fish in a coral reef
Population: group of individual organisms of the same species living in a particular area. Ex: group of sweetlip fish
Communities: all of the organisms inhabiting a particular area.Ex: coral reef is home to fish, coral, animals, microscopic algae and other living things

4. 5 Levels (cont’d)
Ecosystem: includes abiotic and biotic factors in an area. Ex: coral reef living creatures, water, sunlight.
Biosphere: sum of all Earth’s ecosystems
Not spread out evenly.
Patchiness creates different habitats or specific environments for organisms to live.

5. Key Abiotic Factors Sunlight- heats the Earth
Water- essential to all life
Temperature- (0 to 50°C) narrow range for most organisms
Soil
Wind
Severe disturbances

6. Biomes
Biomes- Terrestrial ecosystems that cover large regions of Earth
Tropical Forest: occur near the equator where temperatures are warm year round
Rain forest: 350 cm of rain yearly. Ideal growing conditions for a variety of plants
Madagascar- 8,000 species of flowering plants

7. Biomes
Savanna- grasslands with scattered trees (Africa, Australia, S. America).
Usually a warm climate with alternating wet and dry seasons
Desert: land areas receiving less than 30 cm of rain per year.

8. Biomes
Chaparral- temperate coastal biome dominated by dense evergreen shrubs
Climate consists of mild, rainy winters and hot, dry summers
Ex: California
Temperate Grasslands: deep, nutrient-rich soil that supports a variety of grass species and plants
Ex: S. Dakota (drier), Kansas (wetter)

9. Biomes
Temperate Deciduous Forest- full of trees that drop their leaves each year.
Cold winters and hot summers
Ex: maple, oaks, beeches, and hickory
Coniferous Forest: cone-bearing evergreens
Cold winters, heavy snowfall
Ex: pine, spruce, fir, hemlock

10. Biomes Tundra: bitterly cold temperatures and high winds
Permafrost: permanently frozen subsoil

11. Limits to Population Growth
Carrying capacity- # of organisms in a population that the environment can maintain with no net increase or decrease
Limiting Factor: a condition that can restrict a population’s growth
Ex: space, disease, availability of food

12. Factors Affecting Population Growth
Density-dependent factors: availability of high-quality food  more dense
Density-independent factors: extreme weather conditions (hurricanes, blizzards, ice storms, droughts) effect a population
The same regardless of its size

13. Energy Flow Producers- plants obtain energy from sun
Consumers- organisms that obtain energy from producers and other consumers
Decomposers- breakdown organic material and put nutrients back into environment

14. Food Chains Producers- photosynthetic consumers Herbivores- eat plants
Carnivores- eat other consumers
Omnivores- eat both producers and consumers

15. Consumer classification
Consumers are categorized by their position in the food chain.
Primary- feeds directly on producer
Secondary- eat primary consumer
Tertiary- eat secondary consumers
Quaternary- eat tertiary consumers (usually low)

16. Food Web

17. Carbon Cycle CO2 in atmosphere- used by plants in photosynthesis
Consumers eat producers and release CO2 during cellular respiration

18. Nitrogen Cycle N2 in atmosphere converted to NH3 by bacteria
NH3 becomes NH4+ in soil
Bacteria in soil convert NH4+ to NO3-
Denitrifying bacteria convert NO3- to N2 (back to atmosphere)

19. Water Cycle H2O vapor in atmosphere condensed Precipitation
Groundwater
Absorbed by plants
Transpiration and evaporation put H2O vapor back in atmosphere

20. Energy Flow vs. Chemical Cycles
Energy flows in one direction.
Chemicals recycle.

21. Competition Between Species
Members of a population may compete for limited resources in the environments.
Competition within a single species limits the growth of the population.
Within a community, interspecific competition (competition between species) takes place when 2+ species rely on the same limited resource.

22. Competitive Exclusion
If 2 species are so similar in their requirements that the same resource limits both species’ growth, one species may succeed over the other.

23. Niches
A niche includes an organism’s habitat, its food sources, the time of day it is most active, and other factors specific to its way of life.
No 2 species can occupy the same niche in the same habitat at the same time because of the competitive exclusion principle.

24. Symbiotic Relationships
Symbiotic relationship- close interaction between species in which one of the species lives in or on the other.
Parasitism- one organism benefits; the other is harmed.
Ex: blood-sucking mosquito
Ex: tapeworm that live and feed in the intestines of larger organisms

25. Symbiotic Relationships (cont’d)
Mutualism- both organisms benefit
Ex: a flower’s nectar provides the insect with food and the insect pollinates the flower
Commensalism- one organism benefits; the other is neither harmed nor helped
Ex: spider crab places seaweed on its back to camouflage it from predators, but the seaweed is not significantly affected

26. Global Warming CO2 allows sunlight to pass but traps heat
“Greenhouse effect”- atmospheric gases act like the glass windows of a greenhouse
As levels of CO2 and other “greenhouse gases” rise, average temperatures on Earth rise  global warming