unit 1 bio - Characteristics and Classification of Living Organisms

Movement

An action by an organism or part of an organism that causes a change in position or place.

Respiration

The chemical reactions in cells that break down nutrient molecules and release energy for metabolism.

Sensitivity

The ability to detect and respond to changes in the internal or external environment.

Growth

A permanent increase in size and dry mass.

Reproduction

The process of making more organisms of the same kind.

Excretion

The removal of waste products of metabolism and substances in excess of requirements.

Nutrition

The intake of materials for energy, growth, and development.

Classification of organisms

Organisms are classified into groups based on shared features.

Species

A group of organisms that can reproduce to produce fertile offspring.

Binomial system

An internationally agreed naming system where an organism’s name has two parts: genus and species.

Dichotomous key

A tool that uses a series of questions with two choices to identify organisms.

Purpose of classification systems

To reflect evolutionary relationships.

DNA in classification

DNA base sequences are compared to classify organisms.

Similarity in DNA

Organisms with more similar DNA sequences share a more recent common ancestor.

Kingdom classification (animals vs plants)

Based on features like cell structure, nutrition method, and reproduction type.

Main vertebrate groups

Mammals, birds, reptiles, amphibians, and fish.

Main arthropod groups

Myriapods, insects, arachnids, and crustaceans.

Five kingdoms

Animal, Plant, Fungus, Prokaryote, Protoctist.

Plant group classification

Based on reproduction method: ferns (spores) vs flowering plants (seeds).

Monocots vs dicots

Monocots have one seed leaf, parallel veins; dicots have two seed leaves, net-like veins.

Virus features

Protein coat and genetic material (DNA or RNA); not considered living.