BIOL 2040 Midterm 2 Study Guide PDF

**Origin of Life** - **Chemical Experiments**: Miller-Urey experiment demonstrated that organic molecules could form from simple inorganic compounds under early Earth conditions. - Organic could come from Inorganic - **Protobionts**: Simple, cell-like structures that formed from...

**Origin of Life** - **Chemical Experiments**: Miller-Urey experiment demonstrated that organic molecules could form from simple inorganic compounds under early Earth conditions. - Organic could come from Inorganic - **Protobionts**: Simple, cell-like structures that formed from organic molecules, hypothesized as precursors to cells. - Primitive Cells - RNA is first **History of Life on Earth** - **Environmental Changes**: Oxygenation of the atmosphere, volcanic activity, and glaciation events. - Appearance of oxygen from photosynthesizing bacteria, cyanobacteria - **Changes in Diversity**: Evolution of multicellularity, Cambrian Explosion. - **Origin of Animals**: Emergence of multicellular animals \~600 million years ago. **Prokaryotes vs. Eukaryotes** - **Prokaryotes**: Single-celled, no nucleus (e.g., Bacteria, Archaea). - **Eukaryotes**: Have a nucleus and organelles (e.g., plants, animals). - **Differences**: Membrane-bound organelles, larger cell size, complex reproduction in eukaryotes. **Three Life Domains** - **Bacteria, Archaea, Eukarya**: Based on genetic differences; Archaea and Eukarya more closely related. - Ribosomal Rna to find it **Origin of Eukaryotic Cells** - **Endosymbiosis Theory**: Mitochondria and chloroplasts originated from prokaryotic cells engulfed by ancestors of eukaryotic cells. **Protists -- Do not represent a monophyletic group** - **Evolutionary Relationships**: Diverse group, paraphyletic. - **Metabolic Diversity**: Include autotrophs, heterotrophs, mixotrophs. **Fungi** - **Body Structures**: Mycelium (vegetative), spores (reproductive). - Spores is what you usually see - Break down cell walls, nucleus move around - **Absorptive Heterotrophs**: Decompose organic material. - **Dikaryotic Stage**: Two genetically distinct nuclei coexist before fusion. - Body with two different nucli - **Ecological Role**: Decomposers, symbionts (e.g., mycorrhizae). **Plants** - **Key Characteristics**: Multicellular, autotrophic, alternation of generations. **Alternation of Generations** - **Sporophyte (2n)**: Produces spores by meiosis. - **Diploid** - **Gametophyte (1n)**: Produces gametes by mitosis. - **Haploid** - **More acenstral** **Mitosis vs. Meiosis** - **Mitosis**: Produces identical cells. - **Meiosis**: Produces genetically unique gametes/spores. **Major Plant Groups** - **Bryophytes**: Non-vascular plants (e.g., mosses). - **Vascular Plants**: With vascular tissues. - **Traceophytes** - **Big have to be vascular** - **Non-seeded**: Ferns and allies. - **Seeded**: Gymnosperms (naked seeds) and Angiosperms (protected seeds). - Fern, Conifer, Flowering plants **Evolutionary Trends in Plants** - **Gametophyte to Sporophyte Dominance**. - **Vascular System**: Allowed independence from water. - **Apical Meristems**: Growth at root and shoot tips. - **Seed Evolution**: Protection and nutrient support for embryos. **Animal Development** - **Developmental Stages**: Zygote -\> Cleavage -\> Gastrula -\> Tissue layers. - **Colonial to Multicellular Transition**. - **Tissue Layers**: - **Diploblastic**: Two layers (ectoderm, endoderm). - **Triploblastic**: Three layers (add mesoderm). - **Body Cavity Types**: - **Acoelomate**: No cavity. - **Pseudocoelomate**: Partial cavity. - **Coelomate**: Full cavity. - **Developmental Patterns**: - **Protostome**: Mouth develops first. Blastopore - **Deuterostome**: Anus develops first. **Animal Diversity** - **Protist Ancestor**: Early single-celled ancestor of animals. - **Major Phyla and Key Traits**: - **Porifera**: No true tissues (e.g., sponges). Ancestral - **Cnidaria**: Radial symmetry, stinging cells (e.g., jellyfish). - **Platyhelminthes**: Flatworms, no body cavity. - **Annelida**: Segmented worms. - **Mollusca**: Shell, diverse body plans (e.g., snails, octopuses). - **Nematoda**: Roundworms, pseudocoelomate. - **Arthropoda**: Exoskeleton, segmented bodies (e.g., insects). - **Echinodermata**: Radial symmetry as adults (e.g., starfish). - **Chordata**: Notochord, dorsal nerve cord. **Evolutionary Trends in Animals** - **Multicellularity**. - **Body Plans and Cavities**: Simple to complex. - **Digestive and Nervous Systems**. - **Cephalization**: Development of a head region. **Vertebrates** - **Evolutionary Transitions**: Jawless fish -\> cartilaginous and bony fish -\> amphibians -\> reptiles -\> birds -\> mammals. - **Chordata Traits**: Notochord, dorsal nerve cord, pharyngeal slits, post-anal tail. **The Amniotic Egg** - **Adaptation**: Allows terrestrial reproduction; protective membranes and shell. **Evolution of Mammals** - **Monotremes**: Lay eggs (e.g., platypus). - **Marsupials**: Pouch development (e.g., kangaroo). - **Eutherians**: Placental mammals. **Evolution of Humans** - **Defining Traits**: Bipedalism, large brain, use of tools, complex social structure.