STANDARD 02 Biological Processes

Students will understand that energy from sunlight is changed to chemical energy in plants, transfers between living organisms, and that changing the environment may alter the amount of energy provided to living organisms.

Objective 1 Compare ways that plants and animals obtain and use energy

The Sources of Energy All energy on the surface of Earth comes originally from the sun (photosynthesis) Energy on the bottom of the ocean comes from chemicals (chemosynthesis)

Photosynthesis The process by which plants are able to convert the sun’s energy into chemical energy Chlorophyll (the green pigment inside plants and some algae) absorbs energy in sunlight and combines CO2 and H2O 6CO2 + 6H2O→C6H12O6 + 6O2

Respiration The process by which animals convert food (chemical) energy into mechanical and heat energy Takes place in the animal’s cells using a chemical called ATP – sugar is broken down into CO2 and H2O, releasing energy C6H12O6 + 6O2 →6CO2 + 6H2O

The Path of Energy Solar energy Mechanical energy Chemical energy Chemical energy, Mechanical energy, Heat energy Chemical energy, Heat energy

Objective 2 Generalize the relationships between organisms

Energy Roles An organism’s energy role is determined by: how it obtains energy and how it interacts with the other living things in its ecosystem

Producers Some organisms are able to capture the sun’s energy and store it as food energy They are called producers because they produce all the energy used in an ecosystem

Consumers Can not make their own food or produce their own energy They must eat producers or other consumers

The Cycle Energy enters an ecosystem and moves from producers to consumers to decomposers

Herbivores Consumers that eat only plants

Carnivores Consumers that eat only animals

Omnivores Consumers that eat both plants and animals

Decomposers Break down wastes and dead organisms and return the raw materials to the ecosystem Bacteria and fungi

Scavenger Carnivores that feed on dead organisms

Carrying Capacity The largest population that an ecosystem can support

Predators An animal that hunts and eats other animals

Prey The animal hunted by a predator

Symbiosis A close relationship between two species that benefits at least one of the species

Mutualism The relationship in which both species benefit Saguaro cactus and long-eared bats The saguaro benefits because the bat carries its pollen to another plant The bat benefits because the cactus flowers provide it with food

Commensalism One species benefits and the other is neither helped nor harmed Not very common in nature because two species are usually either helped or harmed a little by any interaction Saguaro and red-tailed hawks The hawk has a place to build a nest The saguaro is not affected

Parasitism One organism lives on or inside another and harms it The parasite is usually smaller and rarely kills the host because it then loses its food supply. A flea, tick, or leech on your body.

Food Chain Shows the movement of energy through an ecosystem A series of events in which one organism eats another and obtains energy

Grass →crickets→frog→snakehawk

Food Web All of the many overlapping food chains in an ecosystem Food Webs are more accurate but more complicated

Relationships between producers and consumers in a food chain The first organism is always a producer The second is always a consumer (first-level consumer) The third is the second-level consumer The fourth is the third-level consumer The different levels are called trophic levels

Energy Pyramid Used to show the amount of energy that moves from one feeding level to another in a food web.

Energy Passed on to the Next Higher Feeding Level At each level, 90% is used to support the organism’s life processes or is lost as heat, so only 10% is passed on Because of this, most food webs only have 3 or 4 feeding levels because there is not enough energy to support more

Objective 3 Analyze human influence on the capacity of an environment to sustain living things.

Species A group of organisms that are physically similar and can reproduce with each other (have “viable” offspring) Hybrids (like a liger) are not a new species because they are sterile (cannot reproduce).

Population All the members of one species in a particular area are a population

Community All the different populations that live together in an area and interact with one another

Ecosystem All the living and nonliving things that interact in a particular area Examples are prairies, mountain streams, deep oceans, or dense forests

Ecology The study of how living things interact with each other and with their ecosystem

Extinction The disappearance of all members of a species

Endangered A species in danger of becoming extinct in the near future Utah sucker

Threatened Species that could become endangered Desert tortoise

Environmental Issues Habitat destruction, pollution, global warming, acid rain, and ozone are all environmental issues that interfere with food chains