Biological Diversity Chapter 15

Chapter 15: Exploring Biological Diversity

• Learning changes everything.
• Essentials of the Living World, Seventh Edition by George Johnson and Joel Bergh.
• Chapter 15 explores biological diversity.

15.1 The Invention of the Linnaean System

• Organisms need names for study and discussion.
• Biologists group organisms using classification.
• Early classification grouped animals and plants into genera (singular, genus).

15.1 The Invention of the Linnaean System

• Modern naming and classification systems were developed by Carolus Linnaeus.
• Linnaeus assigned organisms two-part names, called binomials.
• Linnaeus grouped similar organisms into higher categories based on similar traits.

15.1 (Figure 15.1) Carolus Linnaeus

• A depiction of Carolus Linnaeus.
• Linnaeus lived from 1707 to 1778.

15.2 Species Names

• A taxon (plural, taxa) is a group of organisms at a specific level in a classification system.
• Taxonomy is the branch of biology that identifies and names groups of organisms.
• No two organisms can share the same name; all names are in Latin.

15.2 Species Names

• A scientific name, or species name, is a two-part binomial.
• The first part is the genus (capitalized).
• The second part refers to the species (not capitalized).
• Names are written in italics or underlined.

15.3 Higher Categories

• The binomial system is expanded to a Linnaean system of classification.
• Hierarchy of categories: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

15.4 What is a Species?

• The basic biological unit is the species.
• Members of a species can interbreed and produce fertile offspring.
• The biological species concept defines species as reproductively isolated groups.
• This concept works well for animals but might not be suitable for organisms with asexual reproduction.

15.4 What is a Species?

• The biological species concept isn't always used for plants and other organisms.
• Molecular data are prompting reevaluation of traditional classification systems.
• Approximately 1.5 million species have been named.
• The actual number of species is likely much higher.

15.5 How to Build a Family Tree

• Phylogeny is the evolutionary history of an organism and its relationship to other species.
• Scientists use various methods to construct phylogenetic trees.

15.5 How to Build a Family Tree

• Cladistics infers phylogeny based on similarities.
• Derived characters are traits present in a group that arose from an ancestor lacking that trait.
• A clade is a group of related organisms sharing a derived character.
• Cladograms (branching diagrams) represent a species' phylogeny based on derived trait distributions.

15.5 (Figure 15.6) Cladogram of Vertebrate Animals

• A cladogram showing the evolutionary relationships of vertebrate animals.
• Features like jaws, lungs, hair, and amniotic membrane are shown as derived characters.

15.5 How to Build a Family Tree

• Traditional taxonomy is another approach to constructing phylogenies.
• Information on morphology and biology is used.

15.5 (Figure 15.7) Two Ways to Classify Terrestrial Vertebrates

• A comparison of traditional phylogeny/taxonomy and cladistic approaches.

15.6 The Kingdoms of Life

• Most biologists use a six-kingdom system (proposed by Carl Woese).
• Four kingdoms (Animalia, Plantae, Fungi, and Protista) are eukaryotes.
• Two kingdoms (Archaea and Bacteria) are prokaryotes.

15.6 The Kingdoms of Life

• The domain level was created to reflect distinctions among prokaryotes.
• Domain Archaea encompasses Kingdom Archaea.
• Domain Bacteria encompasses Kingdom Bacteria.
• Domain Eukarya includes the eukaryotic kingdoms.

15.7 Domain: A Higher Level of Classification

• Bacteria are the most abundant organisms on Earth.
• There are various bacterial types, and relationships are often unclear.
• Bacteria play essential roles in the biosphere.

15.7 Domain: A Higher Level of Classification

• Archaea, also prokaryotes, share key traits with eukaryotes but differ from bacteria in various aspects, e.g., cell walls, lipids, rRNA sequences. Intracellular, circular genetic material.
• Archaea are often found in extreme environments.

15.7 Domain: A Higher Level of Classification

• Eukaryotes emerged about 1.5 billion years ago.
• Three multicellular kingdoms (fungi, plants, and animals) dominate.
• Protista (the remaining eukaryote kingdom) is a diverse group of primarily unicellular organisms not fitting other kingdoms.

15.7 Domain: A Higher Level of Classification

• Mitochondria and chloroplasts are believed to have stemmed from bacteria entering early eukaryotic cells via endosymbiosis.

15.7 (Figure 15.12) Endosymbiosis

• Illustrates the endosymbiosis theory.

15.7 (Table 15.1) Characteristics of the Six Kingdoms

• A table summarizing characteristics (e.g., cell type, presence of a nucleus, mitochondria, chloroplasts, cell wall, method of reproduction, nutrition, motility, multicellularity) comparing Domains Bacteria, Archaea, and Eukarya in their kingdom forms (e.g., Plantae, Animalia, Protista).

Explore Chapter 15 of 'Essentials of the Living World' which delves into biological diversity and the significance of classification systems. Learn about the contributions of Carolus Linnaeus and the structure of species naming. This chapter emphasizes the importance of taxonomy in understanding organisms.