Biology Is the Study of Life

Living things,

from simple

cells to

complex

multicellular

organisms,

share common

features and

characteristics

Characteristics of Life• Organization • Metabolism• Acquisition and Utilization

of Energy• Acquisition and Utilization

of Matter• Homeostasis• Response to

Environmental Stimuli• Evolution• Genetic Transmission• Reproduction• Development, Growth,

Maintenance, Repair

The Unity In Life’s Diversity Theme is Evolution

The vast diversity of life forms on the planet have evolved to their present form from a common ancestor.

Nature selects successful organisms who survive to reproductive maturity, therefore, differential reproduction ensures survival of the fittest, best adapted species.

Living things are interactive through the transfer of energy and interconnected through cycles of matter.

Organizational Hierarchy

• Atoms to molecules• Molecules to macromolecules• Macromolecules to organelles• Organelles to cell (unicellular or

multicellular organisms)• Cells (multicellular) to tissue• Tissues to organs• Organs to systems• Systems to organisms• Like organisms compose a

species• Members of the same species

compose a population• Different population compose a

community• Communities compose

ecosystems• Ecosystems compose biomes• Biomes compose the biosphere

Organisms Maintain Order and Organization

• According to the Second Law of Thermodynamics, Entropy, which is disorder, is always increasing in the universe.

• Living organisms use energy and macromolecules from food to maintain organization through metabolism.

Energy Flow and Cycles of Matter Form Interacting and Interconnecting Webs

• Producers transform energy and use it to chemically bond molecules to produce food.

• Both producers and consumers transform the energy in food and use it and the molecules in food to maintain organization and do work.

-Decomposers recycle matter

• Matter is recycled, energy is not.

• Metabolism- sum total of all of the chemical reactions that maintain an organism functioning.

Homeostasis Maintenance of Optimal Ranges and Conditions

• Internal consistency of temperature, pH, concentrations of sugars, electrolytes, etc.

• Along with optimal conditions, for metabolic reactions to occur the following are necessary:

• Enzymes• Energy

Feedback Loops Establish Homeostasis

Response to Environmental Stimuli

• Response to internal environmental stimuli by feedback loops to maintain homeostasis -short range responses are mediated by the nervous system.-long range responses are mediated by the endocrine system.

• Response to external environmental stimuli is also necessary to maintain homeostasis, as well as for survival.

• Nature selects the fittest for survival “Evolution”

Change in pigmentation to camouflage ensures survival.• Organisms must respond to environmental stimuli in order to survive, as well as to maintain internal homeostatic balance. •Adaptations are features that allow organisms to survive in their environment.

Reproduction and Genetic Transmission

• Genetic transmission ensures the inheritance of traits that are successful for survival.

• Inheritance, from parent to offspring, through genes, which are contained on the DNA of the chromosomes and in some cases the mitochondria. In some viruses the genes are on the RNA.

• Expression of genetic traits provide instructions for development, growth, metabolism, etc.

• Members of a species have the same kind and number of chromosomes

Development, Growth, Maintenance, and Repair

• Living organisms must put their genes into action through the development, growth, and maintenance of their body’s organ systems to fulfill their roles as successful members of their species, which is to reproduce effectively.

The uniquecharacteristics of life are a common theme in bothsimple organisms and complex organisms, whether unicellular or multicellular, whether prokaryotic or eukaryotic.