Question

guided notes worksheet: crash course biology #19 – taxonomy: lifes filing system

1. introduction to taxonomy
2. taxonomy is the science of _______________.
3. according to the video, taxonomy helps tell the story of _______________.
4. why do we classify living things?
5. the video compares taxonomy to what organizational system?

(hint: something used in libraries.)
answer: _______________

1. why is classifying organisms helpful for scientists?

answer: _______________

1. phylogenetic trees
2. a phylogenetic tree shows _______________.
3. what does branching represent on a phylogenetic tree?

answer: _______________

1. traits used in classification
2. define analogous (homoplasic) traits:

answer: _______________

1. define homologous traits:

answer: _______________

1. why is the difference between these types of traits important in taxonomy?

answer: _______________

1. taxa & binomial nomenclature
2. what is a “taxon”?

answer: _______________

1. what is binomial nomenclature?

answer: _______________

1. who developed this naming system?

answer: _______________

1. the three domains of life

fill in the three domains and the major characteristics mentioned in the video.
domain 1: _______________
key characteristics: _______________

• example organisms: _______________

domain 2: _______________

Explanation:

All answers are based on content from Crash Course Biology #19: Taxonomy: Life's Filing System.

1. Answers address core taxonomy definitions, purposes, and key concepts from the video.
2. Phylogenetic tree and trait definitions align with standard biological taxonomy terminology from the lesson.
3. Binomial nomenclature and domain details match the video's coverage of modern taxonomic systems.

Answer:

1. Classifying living things
2. all life on Earth
3. The Dewey Decimal System
4. It helps scientists organize, identify, and study organisms, and see evolutionary relationships.
5. evolutionary relationships between organisms
6. Branching represents the point where a single species split into two distinct, new species.
7. Traits that are similar in structure/function but evolved independently in unrelated organisms (not from a common ancestor).
8. Traits that are similar in structure and come from a shared common ancestor.
9. Using homologous traits helps correctly map evolutionary relationships, while confusing them with analogous traits can lead to wrong taxonomic groupings.
10. A taxon is any level of group in the taxonomic classification system (e.g., species, genus, family).
11. Binomial nomenclature is the two-part scientific naming system for organisms, using a genus and species name.
12. Carolus Linnaeus
13. Domain 1: Bacteria

Key characteristics: Prokaryotic, single-celled, have cell walls with peptidoglycan

• Example organisms: E. coli, Streptococcus

1. Domain 2: Archaea

Key characteristics: Prokaryotic, single-celled, live in extreme environments, cell walls without peptidoglycan

• Example organisms: Thermophiles, halophiles

1. Domain 3: Eukarya

Key characteristics: Eukaryotic (cells have a nucleus and organelles), includes single-celled and multicellular organisms

• Example organisms: Humans, trees, mushrooms, amoebas