Module 2
Monday, January 20, 2025
3:52 PM
Characteristics of Life
Organisms - an individual, living creature.
7 widely accepted characteristics of living organisms:
Order (anatomical features)
Evolutionary adaptation
Regulation (tendency toward stability)
Energy processing (convert food to energy)
Growth and development
Response to their environment
Reproduction
Order - Highly ordered structures are comprised of the basic unit of life (the cell). Life is then structured
into developmental hierarchy, where cells give rise to tissues, tissues to organs, etc. The cell, being the
most basic unit of life, is also highly ordered since it contains organelles, cytoplasm, it conducts
metabolic processes, as well as undergoes adaptations.
Evolutionary Adaptation - It refers to smaller, genetic changes that allow for better survival of an
organism, like camouflage, or coat (such as fur) which provides better odds for survival.
Regulation - Living organisms are sensitive to temperature, environmental stress, pH requirements, etc.
and they need to maintain optimal levels (homeostasis), deviations for these optimal conditions require
regulatory processes, e.g. shivering to generate body heat.
Energy processing- Biochemical reactions are utilized to produce energy. The sum of these is referred to
as metabolism. Living organisms must obtain ATP or use metabolic processes to produce their own
energy. Many prokaryotes use organic substances metabolizing them via anaerobic metabolism, plants
use light and create energy via photosynthesis, and animals ingest food and use macromolecules as part
of aerobic respiration.
Growth and Development- All living things grow or change over the course of their life. A living thing
grows, matures, ages, and dies.
Response to Environment- Through adaptation, which is a change that allows an organism to become
better suited for their environment. A stimulus causes the organism to respond, these adaptations can
be physical or behavioral.
Reproduction - Living things must have a way of producing new and thriving generations to replace
previous ones. It may occur through sexual or asexual reproduction. Asexual reproduction examples are,
spore formation, binary fission, vegetative reproduction, budding, and fragmentation.
Levels of Organization, from broadest to smallest.
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Inter organismal (outside of the organism) and intra organismal (inside of the organism) context/levels
of inquiry
Biosphere
o Ecosystem
Communities
Populations
Organisms
Organ Systems
Organs
Tissues
Cells
Molecules and Atoms
Biosphere - broadest level encompassing planet earth and the atmosphere.
Ecosystem - System of living and non-living things in a region. Organisms, soils, and climate conditions
associated are examples.
Communities - all the collective organisms living in a biological ecosystem.
Population - a group of one particular species living within defined boundaries of a community.
Organisms - individual living members of a population.
These are then composed of:
Organ Systems - group of organs classified as a unit because of shared functions.
Organs - structure composed of two or more tissue types, that performs a common function.
Tissues - group of similar cells and the immediate environment surrounding them.
Cells - living structures with organelles that function on a microscopic level to keep the individual alive.
Atoms and molecules- connected by chemical bonds and interactions.
History: Hierarchical system was first developed by Carolus Linnaeus in the 18th century.
Taxon: Unit or level of classification (e.g. species) it refers to each level of classification that forms a
hierarchy.
Taxonomic levels (broadest to smallest)
Domain (3 recognized: Eubacteria, Eukarya, and Archaea)
o Kingdom
Phylum
Class
Order
Family
Genus
Species
Phylogeny: Plotting the evolutionary history of a group or species.
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