BIOL 202 MIDTERM GUIDE EXAM 2025

Microevolution - -change in the frequency of alleles Macroevolution - -large-scale changes that result in selection or extinction of species Homology - -structures that demonstrate evolutionarily close relationships Phylogeny - -evolutionary relationships among species determined from homologous traits Systematics - -science of organizing the history of animal organism evolution Taxonomy - -assigning scientific names according to specific rules Asymmetry - -lack of symmetry Radial symmetry - -one axis of orientation Biradial symmetry - -can only fold one way Pentaradial symmetry - -can fold many ways Bilateral symmetry - -two axes of orientation Unicellular - -single-celled aggregates (protists) Diploblastic organisms - -cells devised into tissues and two embryonic cell laters (tissues have to work together) Triploblastic organisms - -three embryonic cell layers (ectoderm, mesoderm, endoderm) Coelom - -body cavity entirely surrounded by mesoderm Acoelomate - -has no cavity Pseudocoelomate - -cavity not fully surrounded by mesoderm Deuterstomes - -radial cleavage, blastosphere develops into anus, no trochophore larva Protosomes - -spiral cleavage, blastosphereinto mouth, trochophore larva Three domains of life - -bacteria, archaea, eukarya Biology 202 Biology 202 Biology 202 Protists - -a eukaryotic organism that cannot be classified as an animal, plant, or fungus. Pellicle - -a firm, flexible coating outside the plasma membrane Contractile vacuole - -the cell structure that collects extra water from the cytoplasm and then expels it from the cell Cytopharynx - -tubular invagination lined with cilia where food enters and food vacuoles form Binary fission - -a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size Schizogony - -asexual reproduction by multiple fission Budding - -a new organism grows by mitosis and cell division on the body of its parent Excavata - -the eukaryotic supergroup that contains flagellated single-celled organisms with a feeding groove Amoebozoans - -a member of a clade of protists that includes amoebas and slime molds and is characterized by lobe-shaped pseudopodia. Rhizaria - -the eukaryotic supergroup that contains organisms that move by amoeboid movement Alveolata - -a eukaryotic superkingdom, defined by the presence of cortical alveoli, small vesicles that, in some species, store calcium ions. Malaria life cycle - -◊ life cycle • transmitted via mosquitoes - in sporozoite form inside bugs - delivered into blood stream when bitten • travel to the liver and begin their infection there - may become dormant - may reinfect the liver after spreading throughout the body • hypnozoites are then released into the blood stream Biology 202 ◊ they then attack the red blood cells • schizonts then accumulate in the rbc until it bursts ◊ when the schizonts and merozoites are released, the immune reaction begins • travel throughout the body and infect other rbcs and replicate in there • merozoites are asexual • some may become gametocytes (sexual) ◊ gametocytes can enter a mosquito • produce sporozoites • can then infect another victim Metazoans - -- multicellular animals - appear before cambrian period Colonial hypothesis - -a dividing protist remained together Phylum porifera (bearing pores) - -aka sponges; means animal that contains holes; are sessile feeders (stuck to the ground, eating what comes near them); body symmetry: asymetric, can be sexual and asexual Choanoflagellates - -protists that are the closest living relatives of animals Cnidaria (stinging) - -jellyfish, coral - radial symmetry - diploblastic - simple nervous system - most species marine - have polyp and medusa stages (through budding) Cnidocytes - -special stinging structures on cnidarians Hydrostatic skeleton - -a fluid skeleton in many soft-bodied invertebrates, including annelids, that allows an organism to change shape but not volume. Hydrozoan - -a class of cnidaria where most of the organisms alternate between polyp and medusa except hydras, which are only polyp. They can reproduce both asexually and sexually. Scyphozoa - -true jellyfish Cubozoa - -box jellies Biology 202 Biology 202 Anthrozoa (flower, animal) - -sea anemone and coral Ctenophora (comb animal) - -comb jellies -diploblastic -biradial symmetry -opening for mouth and anus -two tentacles Placozoa - -organism with no shape - flagellated upper cell layer and ciliated bottom layer Throchophore larva - --band of cillia -complete digestive system -ciliated tentacles around mouth Platyhelminthes (flat) - -flatworms, tapeworms - no defining feature -much of body is unspecialized cells - bilateral symmetry - incomplete gut - primitive nerve systems Turbellaria - -free-living flatworms - excretion through tubes on either side