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58 Cards in this Set
- Front
- Back
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What is example of primary and secondary succession and describe the stages
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Primary succession: Area covered by lava
1) Appearance of simple plants, lichens and mosses because they are able to spring up from cracks where water and minerals collect (pioneer plants) 2) when they die they decompose to form soil and more complex plants like grasses herbs and small herbs form annual plants which only live one year but leave behind a lot of offspring 3) those plants die and soil will continue to support larger trees and shrubs final stage- those trees become larger and a complex community forms secondary succession is generally the same except that the first stage begins with annual plants like weeds |
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the study systematics
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is the study of biological diversity and its origins. It focuses on understanding evolutionary relationships among organisms, species, higher taxa, or other biological entities, such as genes, and the evolution of the properties of taxa including intrinsic traits, ecological interactions, and geographic distributions
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binomial nomenclature
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binomial nomenclature is the formal system of naming species whereby each species is indicated by a two-part name, a capitalized genus name followed by a lowercase specific epithet or specific name, with both names italicized (or underlined if handwritten, not typeset) and both in (modern scientific) Latin
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Taxon
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A taxon (plural taxa), or taxonomic unit, is a name designating an organism or a group of organisms
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Higher taxa
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The names (taxa) that rank above (i.e., are more generalized) than the species level (e.g., genus, family, order, phyllum, and kingdom)
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Type specimen
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A type specimen is a preserved specimen designated as a permanent reference for a new species, new genus or some other taxon. The type is the first specimen bearing the new scientific name, and the one true example of the species. Since they are considered permanent reference specimens, types are the most important specimens in a herbarium; they anchor their species.
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plesiomorphic
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Features shared more widely than in a group of interest. These are primitive for the group in question and cannot provide evidence for the group.
An evolutionary trait that is homologous within a particular group of organisms but is not unique to members of that group (compare apomorphy) and therefore cannot be used as a diagnostic or defining character for the group. For example, vertebrae are found in zebras, cheetahs, and orang-utans, but the common ancestor in which this trait first evolved is so distant that the trait is shared by many other animals. Therefore, possession of vertebrae sheds no light on the phylogenetic relations of these three species. |
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apomorphic
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A novel evolutionary trait that is unique to a particular species and all its descendants and which can be used as a defining character for a species or group in phylogenetic terms. Hence, the possession of feathers is unique to birds and defines all members of the class Aves. An apomorphy that is restricted to a single species is termed an autapomorphy
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monophyletic group
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A monophyletic group is a group which contains all the descendants of a common ancestor: the group has a common ancestor unique to itself. It is the only group recognized by cladist classification. Monophyletic groups contain all the branches below a given ancestor; nothing is said about the phenetic evolution of species within each branch.
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homology
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homology refers to any similarity between characteristics that is due to their shared ancestry
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homoplasy
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Homoplasy occurs when characters are similar, but are not derived from a common ancestor
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when does Divergent evolution occur?
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Divergent evolution occurs when a group from a specific population develops into a new species in order to adapt to various environmental conditions, the two groups develop into distinct species due to differences in the demands driven by the environmental circumstances
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convergent evolution
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represents a phenomenon when two distinct species with differing ancestries evolve to display similar physical features
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evolutionary reversal
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reverting to the older form or more primitive form of species
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in group
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the monophyletic set of species whose relationships we wish to infer
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out group
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distantly related taxa
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sister group
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groups derived from common ancestor that is not shared with any other groups
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clade
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A clade[note 1] is a monophyletic group - that is, a single common ancestor and all its descendants.[note 2][1] The common ancestor of any reasonably sized group, and many of its descendants, will be not be living.[note 3] It is not necessary for a clade to contain living representatives.
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what are the taxonomic categories of hierarchical classification?
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kingdom, phylum, class, order, family, genus, and species
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how should species names be written?
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consist of the genus and its specific epithet both of latin or latinized words always italicized or underlined and the genus is always capitalized
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what are the two rules of nomenclature
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the first rule is no two species of animals can have the same name the second rule is priority the valid name is the oldest one
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phylogenetic tree
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the tree of life shows relationships and lineages diverging from common ancestors and give rise to both extinct and extant species
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compare ancestral and derived character states
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ancestral state are found in common ancestor derived are those that have evolved from the ancestral state
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why are synapomorphies important in determining species relationships
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these are shared derived character states shared derived states that help decide which groups are sister taxa with in a clade
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what are three complications in inferring phylogenies
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1. the rate of evolution can be misleading because then number of evolutionary change is the most parsimonious
2. Homoplasious characters a similar feature occurs in different species but their immediate common ancestor was different and did not have the feature. They are functional adaptations. E.g. Anteater features in eutheria, metatheria and prototheria • Convergence: two species with similar phenotype whose common ancestor is very far in the distant past. Independent genetic origin. E.g. the hydrodynamic morphology of marine predators from the widely separated fish, reptile and mammalian classes and evolutionaty reversal can also make it difficult |
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what is maximum parsimony? how is it used to infer phylogonies
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Parsimony refers to the principle that states that the simplest explanation requiring the least number of undocumented assumptions, should be preferred over more complicated hypotheses that require more assumptions for which evidence is lacking.
• The best estimate of true phylogeny requires the fewest number of evolutionary changes. |
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punctuated equilibria
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instead of a slow, continuous movement, evolution tends to be characterized by long periods of virtual standstill ("equilibrium"), "punctuated" by episodes of very fast development of new forms
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punctuated gradualism
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is selection and variation that happens more gradually. Over a short period of time it is hard to notice. Small variations that fit an organism slightly better to its environment are selected for: a few more individuals with more of the helpful trait survive, and a few more with less of the helpful trait die. Very gradually, over a long time, the population changes. Change is slow, constant, and consistent
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sibling species
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Sibling Species are species very similar in appearance, behavior and other characteristics while they are reproductively isolated.
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hybrid zone
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A hybrid zone is an area of contact between two noticably different forms of a species at which hybridization takes place. A hybrid zone is a necessary stage for parapatric speciation to take place.
Hybrid zones are examples of stepped clines. A cline is a geographic gradient in the frequency of a gene and stepped clines have more dramatic gradients. A hybrid zone can develop into a species barrier by the process of reinforcement |
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allopatric population
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is the evolution of reproduction barriers in populations that are prevented by a geographic barrier from exchanging genes at more than negligible rate distinction made by vicariance (divergence of two large population)
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parapatric population
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neighboring populations between which there is a modest gene flow diverge and become reporductively isolated
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sympatric population
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is the evolution of reproductive barriers within a single initially random mating population
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geographic isolation
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Geographic isolation, or allopatry, is a term used in the study of evolution. When part of a population of the same species becomes geographically isolated from the remainder, it may over time evolve characteristics different from the parent population (due to genetics/genetic change following geographical isolation, then if the geographical barriers are removed (perhaps due to human activity), members of the two populations will be unable to successfully mate with each other. At this point, a new species has emerged. Geographical isolation is thus a key factor in speciation, the formation of new species - also termed allopatric speciation. The animals would mate and eventually become hybrid species
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sister species
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Species derived from a common ancestral species shared by no other species
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how is the fossil record useful in inferring phylogenies?
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Generally speaking fossil sequences are more usueful to gain principles concerning the trends and tendencies of evolutionary development for example there is a strong correspondence betweeen phylogenetic branching order and order of appearance in the fossil record
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what are two major evolutionary trends that are present in the fossil record?
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Dollo'a law complex characters once lost are not regained
Cope's rule parallel trends where average body size increase multiple linages often evolve through similar stages called grades |
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biological species concept vs. phylogenetic species concept
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the biological species concept define species as just being agroup of actual or potentially interbreeding natural populations that are reproductively isolated from other such groups. A phylogenetic species are diagnosably distinct in the genes much more specific and is the smallest group of species
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Compare the three modes of speciation
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aallopatric speciation have a barrier that can be remove making hybrid species and by founders effect parapatric speciation reproductive isolation as a result of gene flow and sympatric speciation genetic difference result in reproductive isolation
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What are the two methods of allopatric speciation
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vicariance
peripatric speciation (foundes effect) |
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why is the concept of sympatric speciation controversial?
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can only occur if a biological barrier to gene exchange arose within a initially random population without any spatial segregation of the incipient species the problem is how would that happen and lower the frequency of intermediate genotypes that can act as a conduit to gene exchange
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what evidence is there to support sympatric speciation?
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Experiments with the Drosophila that have been subjected to disruptive selection in which caused assortive mating which two sub populations formed which had a habitat prefernce. Host races of specialized herbivorous insects partially reporductively isolated because they feed on different host plants.
Disruptive selection and direct selection on mating traits, which should facilitate sympatric speciation, are biologically well supported. Conversely, costs to assortative mating are also widely documented, but inhibit speciation. Evaluating the joint incidence of these key factors may illuminate why sympatric speciation appears to be relatively uncommon. Acronyms and definitions Allopatric: Describes populations that exhibit no geographic overlap and do not exchange migrants owing to complete environmental barriers to dispersal Assortative mating: When individuals select mates that are more phenotypically similar to themselves than expected under random mating Disruptive selection: Selection against phenotypically intermediate members of a population, favoring increased variance Magic trait: A phenotypic trait that influences both an individual's ecological interactions and the probability of mating with individuals possessing similar trait values Parapatric: Describes populations with adjoining ranges that exchange a moderate number of migrants Pleiotropy: When a gene influences two or more traits Reinforcement: The evolution of increased reproductive isolation owing to selection against hybridization Speciation: The evolution of genetically distinct populations (clusters), maintained by reproductive isolation in the case of sexual taxa Sympatry: Describes populations with broadly overlapping geographic ranges Trait-preference mating: When females prefer to mate with males exhibiting specific mating characters, independent of the females’ expression of that character |
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What is an alternative theory that accounts for two closely related species occupying the same location
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disruptive selection against the phenotypically intermediate members of a population favoring increased variance
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what is historical biogeography? How is it related to plate tectonics
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the study of events in the geological history of the Earth and their use to explain patterns in the spatial and temporal distributions of organisms (usually species or higher taxonomic ranks. For example, an explanation of the distribution of closely related groups of organisms in Africa and South America is based on the understanding that these two land masses were formerly connected as part of a single land mass (Gondwana). The ancestors of those related species which are now found in Africa and South America are assumed to have had a cosmopolitan distribution across both continents when they were connected. Following the separation of the continents by the process of plate tectonics, the isolated populations are assumed to have undergone allopatric speciation (i.e., speciation achieved between populations that are completely geographically separate). This separation resulted in the closely related groups of species on the now separate continents. Clearly, an understanding of the systematics of the groups of organisms (i.e., the evolutionary relationships that exists between the species) is an integral part of these historical biogeographic analyses
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In what order did the continents seperate from Gondwanaland?
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160 million years-Africa
125 million india 80 million New Zealand 55 million - AustrAlia- New Guinea 45 million - india collided with with asia and australia seperated from antartica 30 million- south america 15 million- new guinea collided with Asia |
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What effects did the seperation of gondwanaland have on speciation
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the breakup seperated taxa that have members on different land masses and are decendents of common ancestor the distribution based on pure variance
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what is some evidence that support the time table of speciation
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the ratite birds provide evidence because DNA sequence provides evidence around the same sequence and time period during the break up of the land mass to some extent like moas divereged first around 79 million years ago which is consistent with the early 82 million years seperation of New zealand from Gondwanan distribution.
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why are a large number of endemic species on madagascar?
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madagascar is a large island that was the first to split from gondwanaland. About 75% of Madagascar's species are endemic, meaning they live nowhere else in the world. The island is home to strange animals including lemurs (a group of primates), tenrecs (similar to spiny hedgehogs), brightly colored chameleons, the puma-like fossa, and a variety of other creatures. Sadly, due to habitat destruction and hunting, many of Madagascar's unique animals are today threatened with extinction.
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what are two major hypothesis that account for a taxons distribution? Explain
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Vicariance and dispersal are the major hypotheses accounting for the distribution of a taxon.
Dispersal is the one-way movement of individuals from the site of origin to new habitats. This happens in two ways one in which is called range expansion which is continuous movement to favorable habitats; jump dispersal is the movement across barriers. Once the barriers are breached species may disperse together Vicariance is the separation of a taxon by a geographic barrier, e.g. geological, climate, and habitat. Vicariance may account for the presence of related taxa in disjunct areas. Separate populations often become different species, subspecies or higher taxa. |
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Coevolution
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reciprocal genetic change in interacting species in response to natural selection imposed by each on the other
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the three types of co evolution
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specific- two species evolve in response to another
Guild- several species are involved and their effects are not independent Escape and radiate- a species evolves a defense against enemies and is thereeby enabled to proliferate into diverse claude |
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describe two examples
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figs and their pollinators
aphids and the endosymbiotic bacteria that live within in special cells and supply the essential amino acid tryptophan |
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how might coevolution incur a cost as well as a benefit
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when talking about the coevolution and victims you will have to evolve certain adaptations for capturing subduing or infecting their victims and than the defences againgst the predation like getting highly toxic chemical defense and it becomes a matter of tug of war and eventually it will get exhausted and one species may go extinct or reach some kind of equlibrium where they can both survive and prosper
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what is wallace's line? why does it prevent dispersal of australian and asian species
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The Wallace Line (or Wallace's Line) is a boundary that separates the zoogeographical regions of Asia and Wallacea (which is a transitional zone between Asia and Australia). West of the line are found organisms related to Asiatic species; to the east, a mixture of species of Asian and Australian origin are present
27. The Wallace Line, which marks the discontinuity in the distribution of mammals (Oriental vs. Australian), although Wallacea contains very few mammals |
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what are the biogeographic regions of the planet? name the major countries/continents included in three of the regions
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AT=Afrotropical AU=Australasian EP=East Palearctic NA=Nearctic
NT=Neotropical OL=Oriental WP=West Palearctic |
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The Afrotropical Region (AT)
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consists of Africa east of the Fernando de Noronha, Trinidade, and South Sandwich Islands; south of Spanish Sahara, Algeria, Libya, Egypt, Saudi Arabia, and the United Arab Emirates; east of the Maldive Islands and Chagos Archipelago; and north of Antarctica
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The Neotropical Region (NT)
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consists of lands east of Pitcairn and Ducie Islands; south of the Mexican states of Sinaloa, Durango, Zacatecas, San Luis Potosi, and Tamaulipas (Bueno-Soria, personal communication), Andros, Great Inagua, and the Bahama and Caicos Islands; west of Cape Verde, Ascension, and Tristan de Cunha Islands; and north of South Orkney, Elephant, and South Shetland Islands.
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The Eastern Palearctic Region (EP)
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consists of all lands east of the Russian Ural mountains and the Caspian Sea; north of Iran, Afghanistan, oriental China and Taiwan; and west of Midway Island, the Aleutian Islands, Saint Lawrence Island, and Alaska.
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