Chapter 3 and 4 Biosphere, Ecosystems, and Communities

1. Levels of Organization Cells: Basic unit of all life forms. Tissues: a group of similar cells that perform a specific function

Levels inside of us Organs: Group of tissue that work together to preform closely related functions Organ Systems: Group of organs that work together to perform a specific function

Organisms of the levels Species: a group of similar organisms that can breed and produce fertile offspring Population: Group of individuals of the same species that live in the same area Community: Different populations that live together in a defined area.

The Whole Enchilada Ecosystem: All organisms in a defined area and the physical environment. Biome: Group of ecosystems that share similar climates and organisms. Biosphere: All life on Earth and all parts of the Earth where life exists.

What do we study in Ecology? Ecology is the interactions among organisms and between organisms and their environment (Chapter 1) So that means… we are covering everything from the species level up to the biosphere in ecology.

2. Abiotic or Biotic Biotic factors: Any living part of the environment that an organism might interact with, including other organisms. –Ex: Animals, plants, fungi, bacteria, etc… Abiotic factors: Nonliving parts of the environment. –Ex: sunlight, heat, precipitation, wind, soil

How they work together Many biotic factors can be influenced by the abiotic factors. –Ex: Pond Muck Likewise, abiotic factors are also influenced by biotic factors –Ex: leafy canopy, forest pond, roots of a tree

How these all shape the role of the ecosystem They determine the survival and growth of an organism They determine the productivity of the ecosystem where the organism lives

3. The Trophs Autotrophs: Organisms that capture nergy in the form of sunlight or chemicals and convert it into usable energy for cells –Ex: Algae, certain bacteria, and plants Heterotrophs: Organisms that must acquire energy from other organism, usually by ingesting them.

4. Food Chains and Webs Food chain: series of steps in which organisms transfer energy by eating and being eaten. These can vary in length Interactions between food chains leads to what is called a food web.

5. Producers A food chain/web always starts with organisms called producers Producers: autotrophs that support the other organisms by producing energy that they use Can’t have a food chain without them

Consumers Consumers: Organisms that rely on other organisms for energy and nutrients (Heterotrophs) Many different type of consumers. Multiple consumers will be in one food chain, while only one producer.

Types of Consumers Carnivores: Kill and eat other animals Herbivores: Eats producers Omnivores: Eat both animal and plants Scavengers: Eat dead carcasses Decomposers: “feed” by breaking down organic matter Detritivores: Feed on detritus (garbage)

6. Where do they fit in our chain? Picture here

Where do they fit in our web? Picture here

7. Energy Pyramid Each step in a food chain is called a trophic level Producers always make up the first level Various consumers occupy the rest Energy Pyramid: show the relative amount of energy available at each trophic level of a food chain or food web.

10% rule On average, about 10% of the energy available in one trophic level is transferred to the next level Ex: Grass  Cow  Humans The more levels that exist between producer and consumer, the smaller percent of the original energy they get

8. Nutrients Unlike energy (that flows one way), matter is recycled within and between ecosystems (It cannot be destroyed/created) Nutrients: A chemical substance that an organism needs to survive Every organism needs these to build tissues

9. Water Cycle Water is NOT a nutrient but works similarly to the nutrient cycles The movement of water moves between air, ocean, and land.

Water falls to the surface as precipitation (rain). Surface water that flows into rivers to lakes and oceans is called runoff. Some water seeps into the ground and becomes ground water. Water is then sent to the ocean via groundwater or soaked up into the roots of plants. Water from bodies of water evaporates while water from plants transpire. Water vapor then condenses to form rain clouds

Water evaporates Water becomes water vapor Water vapor condenses and form clouds Droplets large enough forms precipitation Water then goes to rivers, streams, and also soil. Process begins over again.

10. Carbon Cycle Carbon is a major component of the 4 main types of molecules that make living organisms

Carbon CYcle Ways we release Carbon into the air –Burning forests –Burning fossil fuels –Carbon Dioxide (CO2) dissolves in oceans and is returned via water vapor –Geological activity (volcanoes) –Animals release CO2 when they breathe –Decomposers break down bodies

Carbon Cycle Ways Carbon is brought back to Earth –CO2 dissolves in rainwater –Plants take in CO2 during photosynthesis Other processes –Passed from organism to organism in food chains –Pressure built up under ground causes organic matter to become fossil fuels

Nitrogen Cycle All organisms need nitrogen to make DNA and proteins Nitrogen gas (N2) makes up 78% of all Earth’s atmosphere Only bacteria can use this form directly though.

Conversion Nitrogen bacteria usually convert nitrogen gas into ammonia though Nitrogen fixation It is then converted again by bacteria into nitrates and nitrites Producers use these for proteins

Decomposers and nitrogen Decomposers return nitrogen to soil as ammonia Producers can use this ammonia Or Soil bacteria converts nitrates into nitrogen gas through denitrification

11. Limiting nutrient A single nutrient that is scarce or cycles very slowly that affects productivity. Ex: Fertilizers: –Contains 3 crucial elements –Nitrogen, phosphorus, potassium –That’s because phosphorus cycles very slowly in nature but is definitely needed for plants.

12. Niche Niche: The range of conditions in which a species lives and the way the species obtains what it needs to survive and reproduce. –AKA It’s the organisms job

13. Competition Occurs anytime two organisms try to use the same resource. –Competition can be between two same species or two different species. Direct competition always produce a winner and a loser.

Competitive Exclusion Principle States that no two species can occupy the exact same niche in the exact same habitat at the exact same time. Ex: Birds in a tree

14. Predation Predation: Interaction between one animal that captures and feeds on another animal. –They affect where prey live and the population size of the prey

Keystone Species A single species that is usually rare in a community yet applies strong control on the structure of the community.

Symbiosis Means “living together” 3 main forms of symbiosis –Mutualism –Parasitism –Commensalism

Mutualism A relationship that benefits both parties involved Ex: Sea Anemone and Clown Fish

Parasitism Relationship where one organism lives inside or on another organism (host) and harms it. Usually does not kill its host

Commensalism A relationship in which one organism benefits and the other gets nothing out of it. Ex: Barnacles on whales

15. Succession A series of more-or-less predictable changes that occur in a community over time. Ecosystems change over time, especially after a disaster. –New species move in while old ones die out.

Primary Succession Succession that begins in an area with no remnants of an older community –Starts anew Pioneer species: The first species to colonize areas.

Secondary Succession A disturbance affects the community but does not completely destroy it New vegetation grows back quickly Usually follows natural disasters Can also be caused by humans (log/farm)

16. Natural vs. Human Natural Usually produces the original community Are common in many communities Human Ecosystems may or may not recover from extensive human-caused disturbances like farming. Ex: farming tropical rain forests changes the soil and doesn’t allow for original growth