Biology

NOTES BIOLOGY 003

Section 1.1

Life shows many levels of organization. All things, living and nonliving, are made of CELLS The properties of life emerge in CELLS An organism may be a single cell or multicelled. In most multicelled species, cells are organized as TISSUES, ORGANS and organ systems.

A POPOLATION consists of individuals of the same species in a specified area. A COMMUNITY consists of all populations occupying the same area. An ECOSYSTEM is a community and its environment. The BIOSPHERE includes all regions of Earth's atmosphere, waters, and land where we find living organisms.

Section 1.2

Life shows unity. All organisms have DNA which holds instructions for building proteins. They inherit the instructions from their parents and pass them on to offspring. By a process called METABOLISM, every cell uses ENERGY and raw materials from the environment to grow and reproduce. Sunlight energy is captured by PRODUSERS, who make their own food molecules from simple raw materials.CONSUMERS survive by feeding on tissues, wastes, and remains of other organisms. All organisms sense changes in the surroundings and respond to them in controlled ways to maintain HOMEOSTASIS.

Section 1.3

Life shows tremendous diversity. Many millions of SPECIES exist; many more lived in the past. Each is unique in some aspects of its body plan, function, and behavior. We group species that are related by descent from a common ancestor. A current classification system puts species in three domains:ARCHAEA,BACTERIA, and EUCARYA. The eukarya includes the PROTIST,PLANTS, FUNGI and ANIMALS

Section 1.4

MUTATIONS change DNA and give rise to new variations of heritable traits.NATURAL SELECTION occurs if a variation affects survival and reproduction. A population is evolving by natural selection when an adaptive form of a trait is becoming more common.

Section 1.5

Scientific methods are varied, but all are based on a logical approach to explaining nature....