Lesson 1: Characteristics and Unifying Themes of Life

This set of vocabulary flashcards covers the fundamental characteristics of living organisms, the hierarchical levels of biological organization, and the relationship between biological structure and function.

Cellular Organization

A characteristic of life where the cell serves as the basic unit of life, and all living organisms are composed of cells where essential chemical processes occur.

Metabolism

The chemical reactions that occur in organisms to process energy and sustain life functions.

Homeostasis

The maintenance of relatively stable internal conditions despite changes in the external environment.

Growth

Biological changes involving an increase in size or cell number.

Development

The changes that occur as an organism matures.

Reproduction

The process by which organisms produce offspring to maintain the continuity of their species.

Irritability / Response to Stimuli

The ability of living organisms to respond to changes in their environment.

Stimulus

A change in the environment that produces a response.

Evolutionary Adaptation

The process where populations evolve over generations as favorable traits increase survival and are passed to offspring.

Cell

The basic unit of life.

Tissue

A group of similar cells working together.

Organ

Structures made of tissues that perform specific functions.

Organ system

Organs working together to perform major functions.

Organism

An individual living thing.

Population

Individuals of the same species living in a shared area.

Community

Populations living and interacting in an area.

Ecosystem

A community interacting with its physical environment.

Biosphere

The sum of Earth's ecosystems and life-supporting zones.

Structure and Function

A major theme of biology where the physical form of a biological structure enables it to perform its particular function.

Red Blood Cells

Cells with a biconcave disc shape and no nucleus, providing increased surface area for enhanced oxygen diffusion and efficient transport.

Dendrites

Structures of a neuron that receive signals.

Axon

The part of a neuron that transmits impulses.

Myelin

A component of a neuron that helps speed up the transmission of impulses.

Alveoli

Structures with thin walls and large surface area adapted for efficient gas exchange.

Root Hair Cells

Cells with long, thin projections, thin walls, and many mitochondria, designed for the absorption and transport of water and materials.