BSCI 124 Midterm: Unit 2 Review (The Evolution of Plants)

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University of Maryland
Biological Sciences Program
BSCI 124
Edgar Moctezuma

Unit 2 Study Guide Part 1 (Lectures 8-11) Lecture 8: Plant Systematics and Darwinian Evolution Taxonomic hierarchy  Kingdom  Phylum  Class  Order  Family  Genus  Species: a set of individuals that are closely related by descent from a common ancestor and ordinarily can reproduce with each other, but not with members of any other species Biological Species concept: Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups A. Lamarckism  Lamarck believed that traits acquired (or diminished) during the lifetime of an organism can be passed to its offspring  This theory was later disproved, but it did introduce the mechanism for evolution and the idea that species can change by some natural process B. Charles Darwin  Introduced the concept of natural selection while observing animals in the Galapagos Islands  Natural Selection: the differential survival and reproduction of individuals with inheritable characteristics – nature is the selective mechanism. 1. This concept operates on the premises of Variation, Overproduction, Competition, and Survival to reproduce  Artificial Selection - selective breeding practiced by humans on domesticated plants and animals  Gradualism- the view of evolution claiming that evolution occurs as a slow and steady accumulation of changes in organism  Punctuated equilibrium- evolution proceeds with periods of inactivity, followed by periods of very rapid evolution Lecture 9: Plant Adaptations and Evolutions 3 types of Natural Selection  Directional Selection- one trait at the extreme of the range is favored over individuals with the average or opposite extreme of the trait  Stabilizing Selection- the average trait is favored over the extreme traits  Disruptive Selection- all of the extreme traits are favored over the average traits Evidence in support of evolution 1. Comparative Anatomy: Animals and plants can have homologous organs (organs with the same evolutionary origin but different functions) and analogous organs (same function but different origins). They can also operate through convergent evolution (unrelated organisms in a similar environment evolve similar adaptive structures), and also carry vestigial organs (non-functional/degenerative organs or parts of organs) 2. Mimicry (a harmless species may resemble a dangerous species) and protective coloration (Coloration that allows an organism to blend with its environment) 3. Developmental Biology/Embryology: Early embryos of different mammal species look very much alike due to the common features that they share. 4. Biogeography: The unequal distributions of organisms on earth which begins with a species originating from one location and spreads out across the world until they encounter a barrier 5. Molecular Biology: Our genes can provide an evolutionary record through our own DNA 6. Fossil record- fossils (traces left by previous organisms) are the most compelling evidence for evolution as they are tracked by the ever growing fossil record The 3 types of Co-evolution/Symbiosis (the long term evolutionary adjustment of one group of organisms to another through cooperation)  Parasitism: The interaction benefits one organism but harms the other one.  Commensalism: One organism benefits from the bond, but the other is not affected in any way  Mutualism: The interactions benefit both organisms (The Endosymbiont Theory is an example of this since chloroplasts and mitochondria are descendants of prokaryotes Lecture 10: Viruses, Bacteria, and Fungi A. Viruses  Made of a protein coat (capsid) and a nucleic acid for information on how to replicate themselves  Not affected by antibiotics since they focus on killing bacterial threats  Viruses are not able to self-replicate, but they still count as living organisms since they can replicate with a host B. Bacteria  Most bacterial species are heterotrophic (obtain food from other organisms) while others are autotrophic (can make their own food)  Can reproduce asexually  The 6 kingdoms Kingdom Archaebacteri Eubacteria Protista Fungi Plantae Animalia a Prokaryoti Prokaryotic Prokaryoti Eukaryoti Eukaryotic Eukaryotic Eukaryoti c or c c c Eukaryoti c Trivia ‘ancient’ Originally Ex. Ex. Obtain Obtains bacteria; classified Algae, Mushroom nutrients by nutrients often live in as plants protozoa; s, mold; photosynthes via harsh due to cell have a rooted is ingestion environments walls cell wall, plants not cellulose C. Fungi  Can act as decomposers by obtaining nutrition from organic matter to recycle nutrients  Composed of branched hyphae, which contributes to spore production  Causes a majority of plant diseases through mycotoxins  Capable of fermenting yeast, brewing alcohol, and producing bread and cheese Lecture 11: Algae, Bryophytes, and Ferns A. Algae  Can be microscopic or macroscopic  Lacks vascular tissues (xylem and phloem) Algae Type Algae division Location Functions/Structure Diatom Heterokontophyta In cool oceans Can provide phytoplankton in aquatic food chains Kelp/Brown algae (Same as Diatom) rocky coasts in Consists of holdfast, temperate zones or stipe, blade, air open seas (Cold bladder/float waters) Dinoflagellates Dinophyta Warm, tropical Chromosomes are oceans always visible in the nucleus Red Algae Rhodophyta Tropical, coastal The algae looks red due waters to accessory pigments (Phycobilins) blocking Chlorophyll a. It also acts as food and habitat for many aquatic species Green Algae Chlorophyta Mostly fresh waters Important source of and land oxygen and food for aquatic organisms. They can also form symbiotic relationships with fungi to make lichens 1. Kingdom Plantae  Plants evolved from charophytes  Over time, the plants gained more advanced traits as they turn into bryophytes (terrestrial plants), ferns (vascular stomata leaves), gymnosperms (seeds), and angiosperms (flowers)  As plants move from the water to land they had to find new ways to obtain enough water
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