Characteristics of Living Organisms

Study Notes

Movement: Living organisms can change position or place; single-celled organisms and animals move as a whole, while fungi and plants can move parts of their body.
Respiration: Involves chemical reactions that break down nutrients to release energy, typically requiring oxygen.
Sensitivity: The ability to detect changes in internal and external environments.
Growth: Characterized by a permanent increase in size and dry mass, observable in unicellular organisms and complex multicellular organisms.
Reproduction: Processes that produce more organisms of the same kind; includes binary fission in unicellular organisms and sexual/asexual reproduction in multicellular organisms.
Excretion: The removal of waste products formed during metabolism, such as carbon dioxide, through various means of expulsion.
Nutrition: The intake of materials necessary for energy, growth, and development; plants (autotrophs) absorb light, while animals (heterotrophs) consume organic materials.

Species Definition: A species is a group of organisms capable of producing fertile offspring.
Binomial Nomenclature: An internationally recognized system for naming species, consisting of two parts representing genus and species.
Classification Hierarchy: Organisms are grouped into Kingdom, Phylum, Class, Order, Family, Genus, and Species, focusing on unchanging traits that differentiate them.
Evolutionary Relationships: Classification reflects phylogenetic connections, indicating organisms with shared features likely descended from common ancestors.

Conservation Efforts: Understanding diversity among organisms supports habitat management and breeding programs.
Common Ancestry: Organisms with numerous shared traits are typically more closely related, suggesting more recent common ancestry.
Historical Grouping: Previous systems relied mainly on morphology and anatomy for classification due to observable characteristics.

DNA Sequences: Closely related organisms exhibit similar DNA base sequences due to fewer mutations over evolutionary time.
Importance of Similarity: The more closely related two organisms are, the more similar their DNA sequences, indicating recent common ancestry.

Dichotomous Keys: Simple classification tools based on identifiable features that help organize organisms.
Five Kingdoms of Life: Initial classification divides all organisms into five kingdoms: Animals, Plants, Fungi, Protists, and Monera.