Introductory Biology II Module 2: Diversity of Life | BIOL 1104 PDF

Module 2: Diversity of life, Single-celled life, Plants, Fungi BIOL 1104 Introductory Biology II 2.1 Diversity of Life BIOL 1104 | Fall 2024 | Sep 24 | 10:00-11:15am Module 2: Diversity of life, Single-celled life, Plants, Fungi Topics for the module 1. Diversity of...

Module 2: Diversity of life, Single-celled life, Plants, Fungi BIOL 1104 Introductory Biology II 2.1 Diversity of Life BIOL 1104 | Fall 2024 | Sep 24 | 10:00-11:15am Module 2: Diversity of life, Single-celled life, Plants, Fungi Topics for the module 1. Diversity of life 2. Single-celled life 3. Plants 4. Fungi M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life Topic 1: Diversity of life 1. Classification and Systematics 2. Phylogenetics M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Tree of Life All life on Earth evolved from a common ancestor From a single point on the tree of life, the three domains of life diverge and then branch repeatedly Figure 12.2 In the evolution of life on Earth, the three domains of life—Archaea, Bacteria, and Eukarya—branch from a single point. (credit: modification of work by Eric Gaba) M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Phylogeny and Systematics The evolutionary history of a species or group of species is called phylogeny. Systematics is the study of organisms with the purpose of deriving their relationships. Fossil record, structure of body parts or molecules used by an organism, and by DNA analysis. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Levels of Classification Taxonomy is the science of naming and group species to construct an international shared classification system Taxonomic classification system (Linnaean system) developed by Carl Linneaus. A hierarchical system that has levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species The groups at the lowest level belong to a series of nested groups M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Levels of Classification inclusive Phylogenetic taxa can be arranged DOMAIN Eukarya into ranks on the basis of KINGDOM Animalia Inclusiveness vs. Exclusiveness. PHYLUM (DIVISION) Chordata CLASS Mammalia The group at each level is called a ORDER Carnivora taxon FAMILY Felidae For example, for lions, they are in the order named Carnivora. GENUS Panthera SPECIES Panthera leo exclusive M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Figure 12.3 At each sublevel in the taxonomic classification system, organisms become more Taxonomic levels move toward similar. Dogs and wolves are the same species because they can breed and produce viable specificity offspring, but they are different enough to be classified as different subspecies. Organisms become more similar as they are closely related The classification system should reflect evolutionary relationships All members of a taxon should have a common ancestor and more closely related than members of other taxa M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Scientific Names Taxonomists assign each species a two-part scientific name, or binomial nomenclature. The first part is the genus: a proper noun The second part, the specific epithet, is used to distinguish each species within a genus: an adjective. Example: "White Oak" = Quercus alba Only genus name is capitalized The entire name is italicized or underlined Sometimes includes an author or year: Pholcus phalangioides Linnaeus Pholcus phalangioides Linnaeus, 1758 M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Other examples of scientific names... Scaptia beyonceae Could also be written as: S. beyonceae Scaptia beyonceae Lessard Scaptia beyonceae Lessard, 2011 Classification: Domain Eukarya Kingdom Animalia Phylum Arthropoda Class Insecta Order Diptera Family Tabanidae Genus Scaptia M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics The problem with common names... M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics Classification and Phylogeny Phylogenetic tree: shows evolutionary pathways and connections among organisms A lineage from a common ancestor A hypothesis that proposes the relationships among organisms M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics 1735: Linnaeus—kingdoms Plantae and Animalia Limitations: bacteria placed with eukaryotes, some protists possess characteristics seen in both plants and animals. 1866: Ernst Haeckel—Kingdom Protista for unicellular organisms. Kingdom Monera added later for cells that lack nuclei. Ernst Haeckel’s rendering of the tree of life, from his 1866 book General Morphology of Organisms, contained three kingdoms: Plantae, Protista, and Animalia. He later added a fourth kingdom, Monera, for unicellular organisms lacking a nucleus. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 1. Classification and systematics 1969: Robert Whittaker—added Kingdom Fungi to make a five-kingdom tree. Empire Eukaryota: organisms with membrane-bound nuclei in cells (Kingdom Fungi, Protista, Plantae, and Animalia). Empire Prokaryota: no nuclei in cells. Kingdom Monera. This timeline shows how the shape of the tree of life has changed over the centuries. Even today, the taxonomy of living organisms is continually being reevaluated and refined with advances in technology.​ M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life Topic 1: Diversity of life 1. Classification and Systematics 2. Phylogenetics M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Phylogenetic Tree Components Branch Points – Represents a common ancestor; divergence of lineage Basal Taxa – Older Taxa found at the bottom of the Phylogenetic Tree Sister Taxa – Two lineages stemming from the same branch point Polytomy – Multiple Taxa diverging from a common ancestor M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Example of Phylogenetic Tree Figure 12.4 A phylogenetic tree is rooted and shows how different organisms, in this case the species and subspecies of living apes, evolved from a common ancestor. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Phylogenetic Tree and Characteristics Branches and branch points also imply significant character/evolutionary changes The branch point that gives rise to organisms with legs is indicated at the common ancestor of mammals, reptiles, amphibians, and jawed fishes. Figure 12.5 This phylogenetic tree is rooted by an organism that lacked a vertebral column. At each branch point, organisms with different characters are placed in different groups. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Limitations of Phylogenetic Trees Closely related organisms don’t always look alike! Different selective pressures! Distantly related may look similar = convergent evolution Branches do not account for length of time, only evolutionary order Long branch ≠ More Time Phylogenetic trees do not grow in one direction after a new branch develops. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Two Degrees of Similarity Evaluation of Morphological characters Genetic evidence Homologous structures: similarity in physical features and genetic sequences. Common origin Implies an evolutionary relationship Figure 12.6 Bat and bird wings, For example, forelimbs of the foreleg of a horse, the flipper vertebrates. of a whale, and the arm of a human are homologous structures, indicating that bats, birds, horses, whales, and humans share a common evolutionary past. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Misleading Appearances Closely related organisms may have major morphological differences due to minor genetic changes. Chimpanzees and Humans share 99% of their genes. Difference in length of arms and legs, and protrusion of jaw. Figure 12.7 (a) The chimpanzee jaw protrudes to a much greater degree than (b) the human jaw. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Two Degrees of Similarity, cont. Analogous characters Superficial similarities of form and function Adaptations formed due to convergent evolution Does not imply an evolutionary relationship For example, wings in insects, birds, and bats. Difference in development signals no sharing of a common ancestor that had a wing. Figure 12.8 The wing of a honey bee is similar in shape to a bird wing and a bat wing and serves the same function (flight). M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Molecular Comparisons Molecular systematics uses DNA (or RNA, or protein) sequences to infer relatedness More similar sequences inferred to mean more recent branching of two species from a common ancestor Less similar sequences inferred to mean lineages are more distantly related Sequences of myoglobin from five different animals are compared to create a phylogenetic tree. Each molecule is colored to show differences from the human protein. Amino acids that are identical are pink, amino acids that are different but similar are lighter pink, and amino acids that are completely different are in white. The heme is shown in bright red. M2 Diversity, single-celled, plants, fungi | 1/4 Diversity of life | 2. Phylogenetics Evolutionary history is documented in genomes Different genes evolve at different rates Example 1: DNA coding for ribosomal RNA (rRNA) changes relatively slowly and is useful for investigating relationships between taxa that diverged hundreds of millions of years ago. Example 2: DNA in mitochondria (mtDNA) evolves rapidly useful to about