LIVING THINGS
CHARACTERISTICS OF LIVING THINGS
All living things….
 Have CELLS—all organisms are made of 1 or more cells
 RESPOND to stimuli—organisms detect and respond to a change in their environment
 REPRODUCE—organisms make more organisms like themselves
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Asexual Reproduction: 1 parent
Sexual Reproduction: 2 parents
Have DNA—DNA is contained in cells and provides instructions for making proteins
USE ENERGY—organisms use energy to carry out the chemical activities of life
GROW & DEVELOP—organisms grow by increasing their # of cells OR by increasing the size of their cell
NECESSITIES OF LIVING THINGS
All living things need…
 FOOD—food provides organisms with the energy and raw materials necessary to carry on life
 WATER—water is necessary for maintaining metabolism. Cells are about 70% water
 AIR—air is a mixture of several different gases including oxygen and carbon dioxide
 SPACE—organisms must have somewhere to live that contains all the things they need to survive
INTERACTIONS OF LIVING THINGS
ECOLOGY: study of the connections/interactions among living things and their environment
An environment has 2 parts:
 BIOTIC—living factors in the environment (trees, plants, insects, humans, etc)
 ABIOTIC—nonliving factors in the environment (water, soil, light, temperature, etc.)
5 Levels of Environmental Organization
 ORGANISM—an individual living thing
 POPULATION—group of individuals of the same species that live together in the same area at the same time
 COMMUNITY—all of the populations of different species that live and interact in an area (biotic)
 ECOSYSTEM—communities of organisms and their nonliving environment (biotic and abiotic)
 BIOSPHERE—the part of Earth where life exists
The way energy moves through an ecosystem can be represented by…
 FOOD CHAIN: Shows how energy in food molecules (sun producers  herbivores  carnivores  scavengers)
 FOOD WEB: diagram that represents the many energy pathways in a real ecosystem
 ENERGY PYRAMID: triangle-shaped diagram that shows the loss of energy at each level of a food chain
NICHE: an organism’s way of life within an ecosystem (what it eats, where it finds shelter, how it reproduces, etc)
HABITAT: the environment where an organism lives
CARRYING CAPACITY: the largest population an environment can support over a long period of time
LIMITING FACTOR: when 1 or more resources become scarce, occurs when a population reaches its carrying capacity