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139 Cards in this Set
- Front
- Back
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What is taxonomy?
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Branch of biology concerned with identifying, describing, and naming organisms.
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What’s the difference between folk taxonomies and scientific taxonomy?
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Phylogenetics, or classification based on kinship (differentiated from systemics)
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Who is the father of modern taxonomy?
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Carolus Linnaeus
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Define binomial nomenclature.
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A two-named system adopted by Linnaeus to replace the unwieldy polynomial naming system.
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What two words make up a species name?
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Genus + specific epithet = species name
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Describe four difficulties in distinguishing what is actually a new species.
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Variability (how much variability is needed to distinguish a new species); sexual dimorphism (males look different than females); clinal variation (superficial changes across a geographical gradient); and hybridization (how much is too much)
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Name the 7 basic categories or TAXA (sing. Taxon) into which organisms are placed.
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Kingdom, phylum (or division for plants), class, order, family, genus, species
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What is meant by “hierarchical classification system”?
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In a hierarchical system, each taxon includes all those below it.
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Which taxon is the most inclusive?
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Kingdom
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Which taxon is the least inclusive?
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Species
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What is systematics?
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The study of the diversity of organisms using information from cellular to population levels
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Define Phylogeny.
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The evolutionary history of an organism; Taxonomy attempts to show the phylogeny of all organisms currently known to biologists
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What are homologous characteristics?
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Similar characteristics due to common ancestry
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What are analogous characteristics?
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Similar characteristics NOT due to common ancestry
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Give two examples of homologous characteristics.
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Radius & ulna (all vertebrates have forearms)
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Give two examples of analogous characteristics.
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Wings on bats, and wings on insects
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What is convergent evolution?
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The acquisition of the same or similar characters in distantly related lines of descent
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Give two examples of convergent evolution.
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Wings on bats and wings on insects
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What tools are used to determine relatedness?
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The fossil record, homology (comparative anatomy), molecular data
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What method analyzes shared derived characters to classify organisms in a phylogenetic tree?
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Cladistics
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What is the tree derived by this method called?
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Cladogram
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What method analyzes similarities of traits to develop a phylogenetic tree?
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Phenetics
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What is the tree derived by this method called?
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Phenogram
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Which method of determining phylogeny requires an out-group to rule out ancestral characteristics?
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Cladistics
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What is an autotroph?
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An organism that makes its own food; that is, it is capable of photosynthesis
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What is a Heterotroph?
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An organism that is not capable of making its own food; therefore it must consume other organisms for energy
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Name two domains of prokaryotes.
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Bacteria & archaea
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Name four kingdoms of eukaryotes.
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protista, fungi, plantae, animalia
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Which kingdom(s) comprises predominantly single-celled organisms?
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Archaebacteria, eubacteria / unicellular protista(?)
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Which kingdom(s) comprises predominantly multi-celled organisms?
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Plantae, animalia, fungi / & multicellular protista(?)
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Which kingdom(s) comprises predominantly motile organisms?
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Protista, animalia
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Which kingdom(s) comprises predominantly non-motile organisms?
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Archaebacteria, eubacteria, plantae, fungi
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Which kingdom(s) comprises predominantly saprophytes?
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Fungi
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Which kingdom(s) comprises predominantly heterotrophs?
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Fungi, animalia / protista(?)
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Which kingdom(s) comprises predominantly autotrophs?
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Archaebacteria, eubacteria, plantae
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Which kingdom(s) reproduce sexually?
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Protista, plantae, animalia, fungi
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Which kingdom(s) reproduce asexually?
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Archaebacteria, eubacteria
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What are Archaebacteria?
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Prokaryotes that seem to be more closely related to eukaryotes at the molecular level than to eubacteria; examples include methanogens, extreme halophiles, and extreme thermophiles
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Who was the originator of the theory of natural selection?
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Charles Darwin
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Who was Charles Darwin’s grandfather, and why did he think evolution had occurred?
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Erasmus Darwin hypothesized evolution based on ontology and vestigial organs.
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What is uniformitarianism?
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Charles Lyell – uniformitarianism; Father of Modern Geology; thought the Earth was old – concept that the same processes in geology have always been occurring.
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Who developed the sciences of comparative anatomy and paleontology, noticing the stratification of the fossil record, but proposed catastrophism to explain it?
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Cuvier
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What is catastrophism?
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Concept proposed by Cuvier that the great flood is the cause of speciation
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Who first suggested a mechanism for evolution – the inheritance of acquired characteristics?
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Lamark
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Who was the geologist that proposed long periods of erosion and uplift to account for today's geology?
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James Hutton
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What is adaptive radiation?
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Evolution of several species from a common ancestor into new ecological or geographical zones
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Give two examples of adaptive radiation.
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Hawaiian honeycreepers, Darwin's finches
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Define niche.
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The ecological role of an organism in a community, especially in regard to food consumption
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What was Lamark’s contribution to our understanding of evolution?
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Acquired characteristics
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Describe the significance of the Galapagos Islands to Darwin. (Finches and tortoises)
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Abundant evidence of evolutionary adaptation
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List and describe three requirements for natural selection to occur.
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Heritable variation, struggle for existence, and difference in fitness
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Define adaptation.
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A derived characteristic that makes the individual better able to survive and reproduce; fitness is the ability to successfully get descendents into future generations
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List and describe four different transitional fossils which support the theory of evolution.
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fossils of sea animals in the mountains; fossils of extinct animals that look enough like living species that they could be ancestors; Eustheopteron (amphibious fish); Seymoria (reptile-like amphibian); Therapsids (mammal-like reptiles; Archeopteryx (bird-like reptile)
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Describe three different vestigial structures used to support the theory of evolution.
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Ostrich wings, human tail bones & large constrictors have pelvic girdles with leg stubs
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What are homologous structures?
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Similar characteristics due to a common ancestor
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Give two examples of homologous structures.
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Vertebrate forelimbs
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Name two structures that exist in all vertebrate embryos, supporting the theory of evolution.
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Postanal tail and pharyngeal pouches in all vertebrate embryos
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List and describe four different biochemical clues that support the theory of evolution.
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All organisms have the same genetic code; all use the same basic molecules; all use 20 amino acids – all L-isomers (none use D-isomers); variation in gene sequences fit evolution theory; variation in protein sequence fit the evolution theory
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Define population.
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All the members of a single species occupying a certain area at the same time
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Define microevolution.
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A variation in alleles in a gene pool; it is evolution that occurs within a population
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What is the Hardy-Weinberg principle?
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Equilibrium of allele frequencies are constant is (1) there are no mutations, (2) there is no gene flow, (3) there is random mating, (4) there is no genetic drift, and (5) there is no selection pressure; a Hardy-Weinberg equilibrium provides a baseline by which to judge whether evolution has occurred. A change in allele frequencies indicates the occurrence of evolution; p + q = 1; p2 + 2pq + q2 = 1
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Describe four causes of microevolution.
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Genetic mutations (new alleles); gene flow (movement of alleles among populations by migration of breeding individuals); non-random mating (inbreeding, sexual selection, and assortative mating), and genetic drift (changes in allele frequencies of a gene pool due to the chance reproduction of a few individuals
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Describe three types of non-random mating.
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Sexual selection (occurs when males compete for the right to reproduce and females choose to mate with males of a particular phenotype); assortative mating (tendency of individuals to mate with those of the same phenotype with respect to a certain characteristic), and inbreeding (mating with relatives)
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What is the Bottleneck Effect?
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An extreme example of genetic drift when populations get so low that genetic variation is affected (cheetahs?)
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What is the Founder Effect?
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The gene pool of populations is more similar to the first occupant of the area than the other populations
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What is meant by the phrase: “Heterozygosity protects the recessive allele”?
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Only exposed alleles are selected and the heterozygote is favored
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Describe a situation in which heterozygosity is actually favored by natural selection.
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Sickle cell anemia; the heterozygote is better against malaria than the homozygous dominant
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Define fitness in an evolutionary context.
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The extent to which an individual contributes fertile offspring to the next generation
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Define speciation.
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The splitting of one species into two or more species or the transformation of one species into a new species over time
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List and describe three types of natural selection.
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Directional selection (when one extreme phenotype is favored the curve shifts); stabilizing selection (which may prevent speciation; extreme phenotypes are eliminated and the intermediate phenotype is favored); disruptive selection (occurs when both extreme phenotypes are favored over the intermediate – can lead to more than one distinct form)
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Which kind of natural selection is most likely to lead to speciation?
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Disruptive selection
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Which kind of natural selection is most likely to prevent speciation?
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Stabilizing selection
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Define species.
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A group of morphologically similar organisms sharing in a common gene pool; capable of interbreeding and producing fertile offspring
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Describe two basic types of reproductive isolation mechanisms that can lead to speciation.
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Prezygotic and postzygotic
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Which is the most efficient?
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Prezygotic, because it wastes less energy on a doomed offspring
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List and describe four different prezygotic isolation mechanisms.
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Habitat isolation; temporal isolation; behavioral isolation; mechanical isolation, and gamete isolation
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List and describe three different postzygotic isolation mechanisms
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Zygote mortality; hybrid sterility, and F2 fitness.
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Define ecology.
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Oikos ("home") & logy ("study of"); the study of interactions of organisms with their environment
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Define population.
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A group of the same species occupying a certain area; at this level, ecologists are interested in factors that effect population growth and success
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Define community.
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A community consists of all populations at one locale (e.g., a coral reef community)
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Define ecosystem.
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Ecosystems contain the community organisms and abiotic factors (e.g., energy flow, chemical cycling)
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Define habitat.
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An organism's habitat is where it lives
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How does habitat quality affect population dynamics in animals?
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The better the habitat for the species, the more biomass of that species can be supported by the habitat.
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How does habitat quality affect population dynamics in plants?
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For plants, there is a self-thinning, with larger individuals but smaller populations
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Define demography.
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Statistical study of populations with regard to density, distribution and rate of growth
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What is population density?
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Reference to how many individuals live per unit area or volume
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Give two examples of how resource limitations affect population distribution.
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Trout need fast water with high O2 concentrations. Desert plant populations trend to uniform due to water limitations.
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Define biotic potential.
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Maximum population growth rate under ideal conditions
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Describe four things that affect biotic potential.
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(1) Number of offspring per reproductive event; (2) Survivorship; (3) Frequency of reproduction; (4) Age at which reproduction begins
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Define cohort.
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All the organisms entering an ecosystem at the same time; members of a population born at the same time
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Define survivorship.
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The probability of newborn individuals of a cohort surviving to particular ages
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Differentiate between the three types of survivorship curves (Types I, II, III).
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Type I – most survive past the lifespan's midpoint; Type II – survivorship decreases at a constant rate throughout the lifespan; Type III – most don't reproduce
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List and describe the three major groups used in age structure diagrams.
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Increasing (pyramid shaped); Stable (looks like a Coca-Cola bottle); Decreasing (looks like a diamond)
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What would the age structure diagram look like for a growing population?
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Like a pyramid – lots of children
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What does exponential growth mean?
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Growth acceleration over time – dramatic population increase
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Define carrying capacity.
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Maximum number of individuals of a species that can be supported by the environment
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Define irruptive growth.
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Also known as Malthusian growth, it is unconstrained exponential growth
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What are r-selected species?
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Produce large number of offspring when young; "breed fast – die young"; an "opportunistic pattern"
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What are k-selected species?
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Allocate energy to survival of self and offspring; "live long – breed slow"; an "equilibrium pattern"
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Traits of an opportunistic pattern
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Small individuals, short life span, fast to mature, many offspring, little or no care of offspring, many offspring die before reproducing, early reproductive age
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Traits of an equilibrium pattern
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Large individuals, long life span, slow to mature, few and large offspring, much care of offspring, most young survive to reproductive age, adapted to stable environment
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Describe two density-independent means of regulating population size.
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Floods, hurricanes, fires
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Describe three density-dependent means of regulating population size.
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Competition, predation, parasitism & disease
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What is meant by the demographic transition in human population growth?
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A decline in mortality followed by a decline in the birthrate
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What is the most effect means of triggering this transition?
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Education & empowerment of women, which delays the onset of childbearing
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Most population growth occurs in less developed countries, but the largest environmental impact is from the more developed countries. Why is that?
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MDCs simply consume more resources than LDCs despite the smaller population
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Define community.
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A group of populations that interact with one another in the same environment
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Define species composition.
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All the species within the community; different communities have different groups of species
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Define biodiversity.
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The variation of life forms within a given ecosystem, biome, or the Earth; Biological diversity in an environment as indicated by numbers of different species of plants and animals; two qualitative measures of biodiversity include richness and evenness
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Are community boundaries always obvious? Why or why not?
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No – due to gradation; communities grade into one another very gradually so that sometimes it is difficult to detect transition
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Describe two different models of community composition.
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Individualistic model (Gleason) & Interactive model (Clements)
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Which community composition model predicts major interdependencies?
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Interactive model
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Which community composition model predicts gradual changes in community composition?
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Individualistic model
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Define tolerance.
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Tolerances are the special range of conditions for an organism that must be met for survival; the tolerance of desert plants to low rainfall is greater than wetlands plants
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How do tolerances fit into the individualistic model of community formation?
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Tolerances and abiotic factors determine community composition
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Describe the Island Biogeography theory.
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Island biodiversity is positively correlated with island size and inversely correlated with distance from the mainland
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Describe Gause’s Principle.
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No two organisms can occupy the exact same niche in the same area at the same time.
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Describe the Competitive Exclusion Principle.
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Modern term for Gause's Principle; no two species can occupy the same niche at the same time
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What is resource partitioning and how does it work?
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"Niche partitioning" – dividing resources and function to accommodate several species
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What is predation and how does it influence the selective pressure on prey organisms?
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One organism feeding on another; Predation places selective pressure on the prey population resulting in an adaptive improvement of the prey population's defenses against predation
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Describe four defensive mechanisms for prey organisms (other than running fast).
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Camouflage (hard to detect the prey); Bluffing (prey appears threatening to predator); Warning colors (prey is brightly colored making it easy to detect, but is also poisonous or comes with some other deterrent characteristic); Mimicry (prey appears like a non-prey species to the predator)
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Why are Monarch Butterflies bright orange?
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To warn of their poisonous nature
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Why do Viceroy butterflies look so much like Monarch butterflies?
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Batesian mimicry; the Monarch is the model and the Viceroy is the mimic
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Define symbiosis.
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"Living together"
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Describe four types of symbiotic relationships.
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Parasitism (parasite benefits, host is hurt); Commensalism (symbiont benefits, host is neither hurt nor helped); Mutualism (both benefit); Amensalism (one is harmed, the other unaffected)
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Define ecological succession.
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The change in plant community composition over time
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Differentiate between primary and secondary succession.
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Primary – where soil does NOT exist; Secondary – where soil exists (also known as "old-field succession)
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What is facilitation, and how does it relate to succession?
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Each stage of succession creates the conditions under which it will be replaced
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Describe two different mechanisms for secondary succession.
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(1) Inhibition – each stage holds on to the site until something happens to them to allow other stages in; (2) Tolerance – all seeds arrive at the same time, but some develop faster – you see the ones developed enough to be obvious
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What is a climax community?
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The culmination of a series of successions leading to a stable community, known as the climax community
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Describe the difference in how the interactive model of communities and the individualistic model account for succession.
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Interactive (Clements): Communities succeeded toward one definite climax community characteristic of a region; Individualistic (Gleason): Time since the last disturbance represents just another environmental gradient
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Ruderal species
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A ruderal species is a plant species that is first to colonise disturbed lands. The disturbance may be natural (e.g., wildfires or avalanches), or due to human influence - constructional (e.g., road construction, building construction or mining), or agricultural (e.g., abandoned farming fields or abandoned irrigation ditches).
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What is a pioneer species?
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The first species to occupy a newly vacated site
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What is a pyroclimax?
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Fire maintained climax
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What is edaphic climax?
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Soils (not climate) determine climax
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What is a keystone species?
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A species responsible for the maintenance of biodiversity; examples include starfish, elephants, and alligators
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Why do exotic species so often become pests?
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No natural predators
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