Concept explainers
One way to determine the number of species on Earth might be to simply count them. You could comb the scientific literature to find all the species that scientists have discovered and named, and then tally up the total number. One attempt to do just that, the Catalogue of Life project, has compiled an online searchable database that listed 1,612,941 species as of 2015. But even the Catalogue of Life can’t tell you how many species are on Earth.
Why doesn’t counting work? Because most of the planet’s species remain undiscovered. Relatively few scientists axe engaged in the search for new species, and nearly all undiscovered species are small and inconspicuous, or live in poorly explored habitats such as the floor of the ocean or the topmost branches of tropical rain forests. So no one knows the actual number of species on Earth. But biologists agree that the number must be much higher than the number of named species. A commonly held view is that the actual number is close to 8.7 million, the number estimated by a recent analysts that used sophisticated statistical methods to extrapolate past trends in species discovery.
How Many Species Inhabit the Planet?
Want to see the full answer?
Check out a sample textbook solutionChapter 17 Solutions
Biology
- In the figure below, each number represents a species. The closer two numbers are on the diagram the more similar the two species. The circles represent taxonomic groups. For example, the diagram shows that 2, 3, 4, and 5 are in the same genus. (Species within a group may be written as 2-5, 11-16 etc. Separate two or more groups with a coma) A. State one species that is in a genus with no other species B. State the species that are in a family with 2 genera C. State the species that are in order with 2 families D. State the species that are in a class with 3 orders E. Deduce whether species 8 is more closely related to species 16 or species 6 F. Explain why three concentric circles have been drawn around species 34 on the diagramarrow_forwardEarly classification systems from Aristotle to Linneaus would have been most like what we now call the ________. 1)biological species concept 2)morphospecies concept 3)phylogenetic species conceptarrow_forwardIf you start conversing with a friend who is not familiar with scientific names, how would you describe how scientists name species and why it is important to name them properly? What is the correct way of writing a scientific name following the rules of binomial nomenclature?arrow_forward
- Below is a phylogenetic tree. Which of the following statements is correct? Species C and D are called sibling taxa because both are derived from the same parent species H. Species F is more related to species K than species D is. Species A, B, and D share a common ancestor of species I. All species shown are currently with us. All of the abovearrow_forwardFor novice biologists, taxonomy and phylogenetics are difficult concepts to understand and keep separate. This confusion is made worse because modern taxonomic methods make use of molecular tools. Write an essay that contrasts taxonomy to phylogenetics and explain how both disciplines are important to our understanding of species and evolution. Your essay should include a description of taxonomy and phylogenetics, as well as a detailed explanation about how information is represented in a phylogenetic tree or a cladogram.arrow_forwardPeople studying fossils have to employ which of the following species concepts? a. The Morphospecies Concept b. The Biological Species Concept c. The Phylogenetic Species Concept d. The Physical Species Conceptarrow_forward
- Biologists assign each organism on Earth to a species containing similar organisms. Related species are grouped into a _________, which is the next-larger type of biological taxon. The scientific name of a species starts with this larger taxon, and ends with a "specific epithet". Group of answer choices Order Genus Class Familyarrow_forwardWhich species concept defines a species as a group of individuals that can reproduce and produce fertile offspring? Morphological species concept Darwinian species concept Phylogenetic species concept Biological species conceptarrow_forwardA taxonomic group that contains species that have similar phenotypes due to convergent evolution is a. paraphyletic. b. monophyletic. c. polyphyletic. d. a good cladistic group.arrow_forward
- Of all taxonomic categories, only species has an objective definition. What is it?arrow_forwardIn which type of classification system are names assigned only to groups that include a common ancestor and all of its descendants? Question 30 options: a system based entirely on evolutionary history a system based solely on cellular structures a system that groups organisms based solely on similar morphologies a system that groups organisms based on similar roles in the environmentarrow_forwardWhat is a taxon? is. a group of related species a group of related families a type of living organisms a group of any rankingarrow_forward