Biology Fairbanks/Wilson/Young The Study of Life Biology Fairbanks/Wilson/Young

Organisms and Their Relationships Ecology – the study of relationships between living organisms and their interactions with their environments are studied.

Abiotic vs. Biotic Factors ABiotic factors Biotic factors – living factors in an organisms environment. Examples: fish, plants, algae microorganisms, fungi Abiotic factors – nonliving factors in an organisms environment. Examples: temperature, air water, soil type, nutrients

Characteristics of Life

1. Cells All living things are composed of and developed from cells. Unicellular organism – composed of only one cell. Multicellular organism – composed of more than one cell.

Sailor’s Eyeball

2. Organization All organisms are organized at both a molecular and cellular level.

3. Energy Use All organisms use energy for growth and maintenance. Energy is used to repair damaged tissues, generate new cells, and manufacture and break down food into useable energy.

4. Response to the Environment All organisms respond to their environment. Response - is a reaction to a stimulus. Behavior – a complex set of responses.

5. Growth All living things grow. Growth occurs through cell division and cell enlargement. Cell Division – the orderly formation of new cells from the parent cell. Cell Enlargement – increase in cell size.

6. Reproduction All species of organisms have the ability to reproduce. Species reproduce either asexually or sexually. How do the offspring produced through asexual reproduction differ from those that reproduce sexually?

Asexual vs. Sexual Reproduction Asexual: an organism makes a copy of it’s genes and cellular material, turning one organism into two daughter organisms that are genetically identical Sexual: two organisms, one male and one female, have to exchange genetic material. Males donate sperm cells, females donate egg cells. Offspring are genetically distinct.

7. Adaptation Organisms have adaptations or traits that give the organism an advantage in an environment.

Six Major Kingdoms Grouping Species

Eubacteria Prokaryotes whose cell walls contain peptidoglycan. Can survive in many different environments. Can be either aerobic or anaerobic depending on the particular organism.

Archaebacteria Thought to be more ancient than bacteria and more closely related to our eukaryotic ancestors. Can live in extreme environments. Their cell walls do not contain peptidoglycan.

Protista Eukaryotic organisms that can be unicellular, multicellular, or colonial. Classified into 3 broad groups – Algae, protozoans, and fungus- like (for example slime molds and mildews).

Fungi Unicellular or multicellular eukaryote. Have cell walls. Lack the ability to move. More than 70,000 known species. Some fungi are parasites.

Plantae All are multicellular and have cell walls composed of cellulose. More than 250,000 species. Form the base of all terrestrial habitats. While most are autotrophic some are heterotrophic relying on other plants for food.

Animalia More than 1 million species have been identified. All are heterotrophic, multicellular eukaryotes. Range in size from a few millimeters to many meters. Most are motile although some lack motility as adults.

Principles of Ecology

Levels of Ecological Organization Organism Population Biological Community Ecosystem Biome Biosphere

Organisms, Populations, and Biological Communities. Population – individual organisms of a single species that share the same geographic location at the same time. Biological Community a group of interacting populations that occupy the same geographic location at the same time.

Ecosystems, Biomes, and the Biosphere Ecosystem – a biological community and all of the abiotic factors that affect it. Biome – a large group of ecosystems that share the same climate and have similar types of communities. Examples: Marine, Tundra, Temperate forest