characteristics and classification of living organisms

Movement

The ability of an organism to change its place or position.

Respiration

Chemical reactions releasing energy from food (glucose + oxygen → carbon dioxide + water + energy).

Sensitivity

Ability to detect and respond to environmental changes (stimuli).

Growth

Permanent increase in size, cell number, or dry mass.

Reproduction

Production of new organisms of the same species.

Excretion

Removal of toxic metabolic waste or excess substances.

Nutrition

Obtaining or making food for energy, growth, and development.

Respiration equation

Glucose + oxygen → carbon dioxide + water + energy.

Photosynthesis equation

Carbon dioxide + water → glucose + oxygen.

Deamination

Amino acids → urea + carbohydrate (urea is excreted).

Egestion

Removal of undigested food as feces (not excretion).

Purpose of classification

Helps scientific study and shows relationships.

DNA analysis in classification

Uses DNA sequences; more similarity = closer relation.

Advantages of DNA analysis

Accurate, fast, cheap, scalable, requires little sample.

Classification hierarchy

Kingdom → Phylum → Class → Order → Family → Genus → Species.

Genus

Group of similar organisms; crossbreeding → infertile offspring.

Species

Organisms that can breed and produce fertile offspring.

Binomial system format

Genus capitalized, species lowercase, Latin name (e.g., Homo sapiens).

Eukaryotes

Cells with nucleus, mitochondria, linear DNA; often multicellular.

Prokaryotes

Cells with no nucleus, looped DNA, plasmids, small ribosomes.

Animals

Multicellular, no cell wall, heterotrophic.

Plants

Multicellular, cell wall of cellulose, autotrophic.

Fungi

Cell wall of chitin, saprophytic or parasitic.

Protoctists

Mostly unicellular; may have chloroplasts or cell walls.

Vertebrates

Animals with a backbone.

Mammals

Hair/fur, live births, mammary glands, four-chambered heart.

Reptiles

Dry scaly skin, leathery eggs.

Amphibians

Moist skin, jelly eggs in water; gills→lungs as they mature.

Birds

Feathers, beak, hard-shelled eggs, wings, scaly legs.

Fish

Scales, gills, fins, jelly-coated eggs.

Invertebrates

Animals without a backbone.

Arthropods

Segmented body, jointed legs, exoskeleton.

Myriapods

Many legs, many body segments.

Crustaceans

5+ pairs legs, 2 body parts, 2 antenna pairs, chalky shell.

Arachnids

4 pairs legs, 2 body parts, no antennae.

Insects

3 pairs legs, 3 body parts, 1 antenna pair, wings, compound eyes.

Flowering plants

Plants with true roots, stems, leaves; produce seeds in flowers.

Monocots

1 cotyledon, narrow leaves, parallel veins, petals in 3s, fibrous roots.

Dicots

2 cotyledons, broad leaves, network veins, petals in 4/5s, tap root.

Ferns

Non-flowering plants; reproduce by spores; fronds, rhizomes; need shady humidity.

Excretion

Removal of toxic metabolic waste (e.g., CO₂, urea, water).

Egestion

Removal of undigested food; not a metabolic waste.