Chapter 13: Energy and Nutrients

Ecology→ the scientific study of interactions between different kinds of living things and between living things and the environment in which they live. Ecologists study the Biosphere-or living world. ↓This is done through 3 basic methods pg.284 fig Observations 2. Experiments 3. Models 13-1

→ Ecologists have found two ecological truths: 1. Our planet is home not only to humans but to many other forms of life as well. 2.The health of human society depends on the well-being of much of that life.

→ At the core of every organism’s interaction with its environment and with other organisms is the organisms need for energy and nutrients- energy to power life’s processes and raw materials to build and maintain living tissue.

* The study of ecology must begin with the study of how different organisms obtain and use energy and nutrients on which all life depends. Section review 13-1 pg.286

Section 13-2 Energy: Essential for life’s processes All of life’s processes require energy ↓both animals and plants require energy→ *only plants (some bacteria) can collect energy from their environment and harness it to do biological work. → Animals can store energy in forms of carbs. or fat, but an animal must eat something to obtain energy.

Energy from the Sun Plants harness energy from sunlight by a process called photosynthesis. ↓ use this energy to build carbs., fats, and proteins. Primary producers: Plants are Primary producers. ↓ use energy from sun to make food. ↓ also called autotrophs. Consumers: Animals can’t build their own building blocks (carbs, fats, and proteins) Animals must eat→ therefore they are called consumers or Heterotrophs.

Heterotrophs → There are different types of heterotrophs: Herbivores- obtain energy by eating autotrophs (plants). Ex. Cow Carnivores- eat other animals. Ex. Snake Omnivores- eat both plants and animals. Ex. Humans Decomposers- feed on dead bodies. Ex. Flies

Energy flow through the biosphere Energy cannot be recycled in the biosphere→it is called a one way flow. *Arriving as Sunlight, energy flows through the tissues of Primary Producers to the tissues of consumers and then to the tissues of decomposers. Trophic Levels Each step in the series of organisms eating other organisms makes up a trophic level or a feeding level. The greater the # of trophic levels between consumers and primary producers, the smaller amount of energy that is available to the consumers compared to the energy originally captured by the primary producers. The energy chain from primary producers to herb to carnivore creates ecological pyramids.

Section 13-3 Nutrients: Building blocks of Living Tissue. Nutrients: The substances that organisms use to build living tissues and to grow. Plants: Need H₂O, CO₂, P, K, N, Fe, etc, to build carbs. Heterotrophs- must eat other organisms in order to obtain the nutrients. Nutrients→ Either become part of living tissue or they are eliminated from the organism as waste product. ↓Nutrients that are available in fixed quantities on earth are passed from one organism to another and from one part of the biosphere to another through the pathways of nutrient cycles. Nutrient cycles may be limited to smaller parts of the biosphere called ecosystems. ↓An ecosystem’s productivity is a measure of the rate at which energy is captured by its autotrophs. ↓This productivity may be limited by a single nutrient that is in short supply or moves through the ecosystem very slowly (this is known as Nutrient limitation). Ex.) Farmers use fertilizers to combat nutrient limitation ↓contain three plant nutrients (nitrogen, phosphorus, and potassium) ↓help the plant to grow

Pg H₂O Cycle: Consists of the processes of evaporation, condensation, and precipitation.

Nitrogen Cycle: Found in the atmosphere in the soil and in the nucleic acids and proteins that make up the tissues of living things.

Carbon Cycle: Carbon is found on the Earth in three large reservoirs-in the atmosphere as CO₂ gas, in the oceans as dissolved CO₂, and undergrounds as coal, petroleum, and calcium carbonate rock.

13-4: Food Webs In the Biosphere, all organisms are linked together into complex networks based on who eats who. ↓These relationships were thought as simple Food Chains ↓sequence of organisms related to one another as predator and prey. A food web is a better way to explain this ↓show the complex feeding relationship that result from interconnecting food chains. ↓Food webs contain three categories of organisms: Fig a. primary producers b. consumers c. decomposers

Food Web Diversity Coastal Salt Marsh Food Web 1.Few of the animals eat grasses directly. 2. Most of the primary producers die, decompose, and are converted into Detritus.(decaying organism) Marine Food Web- Fig In open ocean, it contains many trophic levels. 2. In an up welling zone, it contains fewer trophic levels. Section Review 13-4 Pg. 295

Marine Food Web