Chapter 17
What is a fossil?
A fossil is the preserved remains or traces of an organism from the past.
What is an index fossil, and why is it useful?
Index fossils help date rock layers because they lived briefly but were widespread.
What is taxonomy?
Taxonomy is the science of classifying organisms.
What is the difference between homologous and analogous structures?
Homologous structures share common ancestry; analogous structures do not.
What are bacteria?
Bacteria are single-celled prokaryotes without a nucleus.
Why is fossilization considered a rare event?
Fossilization is rare because organisms usually decay or are destroyed before preservation.
How does the fossil record provide evidence for evolution?
The fossil record shows how species have changed over time.
Who was Carolus Linnaeus, and why is he important to classification?
Carolus Linnaeus created the modern classification system and binomial nomenclature.
What are the three domains of life?
The three domains are Bacteria, Archaea, and Eukarya.
How do bacteria reproduce?
Bacteria reproduce by binary fission.
Which types of organisms are most likely to become fossils?
Organisms with hard parts fossilize more easily than soft-bodied organisms.
What is a transitional fossil?
Transitional fossils show traits of both ancestral and modern organisms.
What is binomial nomenclature?
Binomial nomenclature is a two-part scientific naming system (genus and species).
How is DNA used in modern classification?
DNA evidence is used in modern classification systems.
What structures are found in a typical bacterial cell?
Bacteria have cell walls, cell membranes, cytoplasm, ribosomes, and DNA.
What is the difference between relative dating and absolute dating?
Relative dating compares ages; absolute dating gives an age in years.
What does the law of superposition state?
The law of superposition states that lower rock layers are older than layers above them.
What are the seven major taxonomic categories from broadest to most specific?
The seven categories are Kingdom, Phylum, Class, Order, Family, Genus, Species.
What is a dichotomous key used for?
A dichotomous key helps identify organisms using paired choices.
How do some bacteria move?
Some bacteria move using flagella.
How does radioactive dating determine the age of rocks or fossils?
Radioactive dating measures isotope decay to determine age.
Why is the fossil record incomplete?
The fossil record is incomplete because not all organisms fossilize.
What is a phylogenetic tree used to show?
A phylogenetic tree shows evolutionary relationships.
How are scientific names written correctly?
Scientific names are italicized, with the genus capitalized and species lowercase.
Why are viruses not considered living organisms?
Viruses are not living and must infect a host to reproduce.