Chapter 3: The Biosphere

Chapter 3: The Biosphere Pages 62-80

Chapter 3-1: What is Ecology? Pages 63-65

ecology species population community ecosystem biome biosphere Hemoglobin is a complex organic molecule in blood that carries oxygen to tissues. It contains the elements carbon, hydrogen, iron, nitrogen, oxygen, and sulfur. Which of the following elements is least common in organic molecules? A. hydrogen B. iron C. nitrogen D. oxygen Vocabulary Brain Candy

Question: How do organisms affect one another’s survival? Answer: No organism can live in isolation. Organisms are interdependent and rely on each other for things like food and shelter.

Ecology • Study of interactions among organisms and between organisms and their environment

Levels of Organization Ecologists Study: • Individual Organism • Species: a group of individuals so similar that they can interbreed and produce fertile offspring in nature • Population: individuals of the same species living together in the same area • Community:different populations living in the same area

Ecosystem: all the organisms in a community interacting with their non-living or physical environment • Biome: a group of ecosystems that have the same climate and dominant communities • Biosphere: the portion of the planet where life exists, including land, water, and atmosphere *Extends 5 miles above earth’s surface and 7 miles below ocean’s surface.*

organism  species  population  community  ecosystem  biome  biosphere

Methods of Studying the Biosphere • Observing: using one or more of the senses to gather information • Experimenting: performing tests in artificial environments that mimic real conditions or within natural ecosystems • Modeling: making predictions based on data collected through observing and experimenting and mathematical formulas

Critical Thinking Question Suppose you wanted to know if the water in a certain stream was safe to drink. Which ecological method would you use and why?

Chapter 3-2: Energy Flow Pages: 67-73

autotrophs producers photosynthesis chemosynthesis heterotrophs consumers herbivores carnivores omnivores decomposers detritivores food chain food web trophic level ecological pyramid biomass A particular protease enzyme breaks proteins down into amino acids within a cell. The optimum temperature for the function of this enzyme is 35° C. Which of the following choices is the best prediction of what could be observed in a cell containing protease? A. The protein concentration in the cytoplasm would be highest at 35° C. B. All the protease molecules in the cell would bind to amino acids at 35° C. C. The amino acid concentration in the cytoplasm would be highest at 35° C. D. No protease molecules would be found in the cell at temperatures above 35° C. Vocabulary Brain Candy

Question: We get energy from our food. Where does our food get its energy? Answer: The SUN! (and some inorganic molecules in soil and water)

Energy Flow • Energy always flows in one direction through an ecosystem – from autotrophs to heterotrophs

Autotrophs • a.k.a. PRODUCERS • organisms that use energy from the environment to change CO2 into organic compounds (food) Two types of producers: • photosynthesizers – use energy from the sun (plants, algae, bacteria) • chemosynthesizers – use energy from chemical reactions inside Earth (bacteria)

Heterotrophs • a.k.a. CONSUMERS • organisms that rely on other organisms for their energy and food supply

Critical Thinking Question We benefit a great deal from plants. But, how do plants benefit from animals?

Types of Consumers • herbivore – plant eater • carnivore – meat eater • omnivore – eat both plants and animals • detritivore – eat dead plants and animals • decomposer – breakdown organic matter into inorganic compounds like CO2, H20, NO3

Feeding Relationships food chain: a series of steps in which organisms transfer energy by eating and being eaten producer → herbivore → carnivore food web: a linking of all the food chains in an ecosystem

Critical Thinking Question Why are straight-line food chains so rare?

Trophic Levels • each step in a food chain or food web • producers make the first trophic level • herbivores make the second level • a.k.a. first level consumers • carnivores and omnivores make up all the remaining levels (3rd, 4th, etc) • a.ka. 2nd, 3rd, etc. level consumers

Critical Thinking Question Can consumers eat within their own level? Can you think of an example?

Ecological Pyramids • A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web • Three types of pyramids: • Energy • Biomass • Numbers

Critical Thinking Question All the plants in a particular pyramid represent 450,000 calories. Here are the next levels in the food chain…indicate the number of calories available to the next level: 1. mice and insects 2. snakes 3. hawks How much energy does the hawk store? How much does it lose as heat?

Critical Thinking Question How would an ecological pyramid of numbers look for a forest ecosystem?

Chapter 3-3: Cycles of Matter Pages 74-80

biogeochemical cycles evaporation transpiration nutrients nitrogen fixation denitrification primary productivity limiting nutrient algal bloom Which of the following members of a forest ecosystem is directly dependent on plants? A. producerB. primary consumerC. secondary consumerD. tertiary consumer Vocabulary Brain Candy

Question: What happens to rain when puddles “dry up”?

Biogeochemical Cycles • process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another • unlike energy, matter is recycled within and between ecosystems in biogeochemical cycles • matter can cycle through the biosphere because biological systems do not use up matter, they transform it

Water Cycle 1. Water molecules enter the atmosphere as a gas • evaporate: from the ocean and other bodies of water • transpiration: evaporation of water from the leaves of plants • aerobic respiration: organisms breath contains water vapor

2.Cloud formation • water vapor loses heat energy and changes back into a liquid (condensation) • liquid water droplets in the air form clouds

3.Precipitation • when water droplets in clouds become large and too heavy they fall back to Earth’s surface in the form of rain, snow, sleet, or hail

4.Water returns to the oceans • runoff – water runs along the surfaces of the ground until it reaches a river or stream that will carry it to the ocean or a lake • seepage – water goes down deep into the ground to become part of ground water • ground water – underground lakes and streams

Critical Thinking Question Question: 95% of the body is made up of C, H, O, N…so how do we get them into our system?

Nutrient Cycles nutrient: a chemical that an organism needs to live Three nutrient cycles: • Carbon • Nitrogen • Phosphorous

1. Carbon Cycle • Carbon is the key ingredient in the organic compounds that make up living things • Of all the carbon on Earth, less then 1% circulated in the biosphere

Carbon Cycle Involves: • biological processes like photosynthesis, respiration and decomposition • geochemical processes like CO2 released from volcanoes • human activity – burning of fossil fuels • conversion of carbon-rich remains into coal and petroleum from pressure of the earth after burial

CO2 is returned to the atmosphere when: • animals break down organic compounds for energy • fossil fuels are burned • decomposers decay the bodies of dead organisms • volcanic activity • “waste product” of aerobic respiration

Critical Thinking Exercise Write a short paragraph describing what could possibly happen to a molecule of carbon dioxide that you breathe out. Use at least seven steps in your cycle. Creativity is a plus!

2. Nitrogen Cycle • 78% of the atmosphere is nitrogen gas • nitrogen fixing bacteria change gaseous nitrogen into nitrogen compounds (nitrogen fixation) • plants absorb these nitrogen compounds through roots and change them into proteins • animals get nitrogen in the form of proteins when they eat plants or other animals

When an organism dies: • decomposers change nitrogen back into nitrogen compounds such as ammonia (some is used by producers) • denitrifying bacteria change ammonia back into nitrogen gas (denitrification) to be released into the atmosphere

Phosphorous in the Biosphere • phosphorus is important in the formation of DNA, RNA, and high energy compounds like ATP • it is not found in the atmosphere • it is found mostly as inorganic phosphates (PO4) in rocks and ocean sediment

3. Phosphorous Cycle • PO4 dissolved in ocean waters is taken in by marine organisms • on the land PO4 dissolved in the soil is absorbed through the roots of plants • plants change these important inorganic PO4 to organic PO4 compounds • animals get PO4 when they eat other organisms

Nutrient Limitations: • primary productivity of an ecosystem is the rate at which producers change inorganic compounds into organic compounds • if a nutrient is short in supply it will limit an organism’s growth • called a limiting nutrient or limiting factor • farmers use fertilizers to overcome limiting factors and increase crop production

Nutrient Limitations continued… • these fertilizers usually contain nitrogen, phosphorus and potassium • if too many nutrients are added to aquatic environments this might lead to increased amounts of algae and other producers • called an algal bloom • if there is not enough consumers to eat the algae the health of the ecosystem can be upset

Critical Thinking Question Question: How does algal bloom actually upset an ecosystem? Answer: The extra algae dies, and decomposing bacteria deplete the oxygen in the lake. As a result organisms that need oxygen, like fish or amphibians, die off.

Critical Thinking Question Native Americans taught European settlers to bury pieces of fish with the seeds of corn they planted. Why might this practice ensure a good harvest? Can you think of a current day practice that is similar to this?

Chapter 3: The Biosphere