Lesson 1 - Introduction to Biology and Scientific Investigation The study of the living world.
Modern biology encompasses all levels of organization and interaction: •
among organic molecules
among organelles within a cell
among cells in an organ
among the organ systems in an organism
between organisms and the abiotic environment
among individuals in a population
among species in a biological community
Knowing the facts of biology without an understanding of the relationships among these levels of organization is insufficient to understand the biological world. How do I know that you are alive?
Life is defined in terms of qualities that the living uniquely share: •
Life is organized
in sequences of increasing complexity (structures within structures) o
the basic unit of life is the cell
levels of biological organization are hierarchical from cells - organisms - communities - biosphere • Life requires energy
the natural tendency of matter is towards disorder (i.e., entropy or randomness) o
living systems acquire and use energy to maintain their highly organized state o
metabolism: the biochemical reactions that acquire and use energy • Living things must maintain an internal constancy
this requires a separation from the non-living world
for metabolic processes to function normally, living things need to keep themselves stable in temperature, moisture level, chemistry, etc. o
homeostasis: the ability to maintain internal constancy (i.e., to stay the same) • Living things grow, develop, and reproduce
vital if a population of organisms is to survive more than one generation> o
"Instructions" for growth and development are encoded in genes • Living things react to environmental change - Irritibility - (an individual reacts to its environment) o
reaction may be immediate as in a reaction to extreme heat, or longer term as in a change in leaf color in response to day length, but certainly within the lifetime of the individual. o
behavior - move towards or away from stimuli
change in metabolism
change in development
• Living things adapt (evolutionary change in a population over many generations) o
an inherited characteristic or behavior enables an individual to live and reproduce with greater success than other members of their population in a given environment o
these adaptations/modifications become more frequent in the population over several generations Of all of the Qualities of Life, the last two, reacting to environmental change and adapting to environmental change are most often confused. An INDIVIDUAL REACTS to environmental change within the range of its lifetime. •
A reaction can be immediate, like the defensive actions of the bombardier beetle picture above. •
A reaction may take longer, like the changes made by your body in reaction to the new hormones produced during puberty. A POPULATION ADAPTS to a changing environment over a longer period of time measured in GENERATIONS of the population. •
"Adaptation", in biological terms, means evolution.
Individuals can not adapt in the evolutionary meaning of the word, but populations can change and become better adapted to a new environment by natural selection. Scientific Inquiry:
The scientific method of investigation involves making a series of inquiries by observing, questioning, reasoning, predicting, testing, interpreting, and concluding. However, because these inquiries spawn new ideas and raise new questions, the scientific method is more like a cycle of inquiry, rather than a simple linear process of investigation. •
Make observations, ask questions, and consult prior knowledge •
After synthesizing this information, formulate a hypothesis - a tentative EXPLANATION of the observed facts (i.e., this is how I think the natural world works) •
Make a prediction based on the hypothesis.
The prediction is often phrased in conjunction with the hypothesis as an "If........then....." statement. o
IF - state your...
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