18.1 A2 Level

Classification

8 flashcards to master this topic

Definition Flip

What is the biological species concept?

Answer Flip

The biological species concept defines a species as a group of organisms that can interbreed in nature and produce viable, fertile offspring.

Example: Lions and tigers can interbreed, but their offspring (ligers/tigons) are infertile, so they are considered different species.
Key Concept Flip

What are the key differences between Archaea and Bacteria?

Answer Flip

Archaea and Bacteria differ in membrane lipids (Archaea have branched isoprene chains, Bacteria have fatty acids), ribosomal RNA (different sequences), and cell wall composition (Archaea lack peptidoglycan, Bacteria have peptidoglycan). Both are prokaryotes.

Definition Flip

List the taxonomic hierarchy from kingdom to species.

Answer Flip

The taxonomic hierarchy is: Kingdom, Phylum, Class, Order, Family, Genus, and Species. This system organizes organisms into increasingly specific groups based on evolutionary relationships.

Key Concept Flip

Outline two characteristic features of the Kingdom Protoctista.

Answer Flip

Protoctista are eukaryotic, mostly unicellular organisms. They exhibit a wide range of nutritional modes, including autotrophic (photosynthetic) and heterotrophic.

Key Concept Flip

Describe the classification of viruses based on nucleic acid.

Answer Flip

Viruses are classified based on their nucleic acid type: either DNA or RNA, and whether this nucleic acid is single-stranded (ss) or double-stranded (ds). Examples include ssRNA (

Example: influenza), dsDNA (. herpes).
Key Concept Flip

Outline two characteristic features of the Kingdom Fungi.

Answer Flip

Fungi are eukaryotic, heterotrophic organisms with cell walls made of chitin. They obtain nutrients through absorption, often acting as decomposers or parasites.

Key Concept Flip

Outline two characteristic features of the Kingdom Plantae.

Answer Flip

Plantae are eukaryotic, multicellular organisms that are autotrophic (photosynthetic) and possess cell walls made of cellulose. They are primary producers in many ecosystems.

Key Concept Flip

Outline two characteristic features of the Kingdom Animalia.

Answer Flip

Animalia are eukaryotic, multicellular, heterotrophic organisms that lack cell walls. They obtain nutrients through ingestion and have complex organ systems.

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17.3 Evolution 18.2 Biodiversity continued