Term
| Central research focus in macroevolution |
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Definition
| Purpose is to understand what regulates biodiversity over geological time. These events must be the sum of species level micro-evolutionary processes and community -level ecological processes |
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Term
| How to approach macroevolution |
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Definition
Since there is only a single history of life the approach is to
1) look for repeating patterns within that history
2) Try to identify causal factors that are extensions of known microevolutionary and ecological processes.On this scale units are species and the causal factors may relate to plate tectonics and other abiotic factors |
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Term
| Are there limits on species diversity? |
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Definition
| It is widely accepted that resources limit the number of individuals in a population, iti is far less clear hwo resoureces could place limits on the number of species. Species richness does vary with latitude, but for macroevolution abiotic factors, rather than resource limitation may play significant role |
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Term
| What types of abiotic factors can affect species richness |
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Definition
| When examining the various configurations of continents, when the continents are spread (measles) as opposed to belt or beret you can have up to 100x species richness. |
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Term
| concept of island biogeography and alterations |
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Definition
| The point of this was to determine the idea of an equilibrium state in species richness. that results from a balance of colonization and extinction rates. You subsitute colonization with speciation and you also add the idea that extinction might not be competition dependent but rather sine are due to diversity independent modes. |
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Term
| Applicability of equilibrium biodiversity and DI extinction to population biology |
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Definition
| Here the terms in standard logistic growth curve model can be changed to represent the idea of DI extinction. DD extinction (which was what we used before when reached k) now shows up to a 33% difference between it and the curve for DI, which demonstrates that ecosystem at euqilibrium following DI patterns contain many unfilled niches. |
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Term
| Focus on species in fossil record as analytical units |
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Definition
| By doing so, one can disect the single history contained in the fossil record into multiple replicated cases Afterwards can apply individuality of species to ask about causality in physiological, behavior, or ecological terms |
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Term
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Definition
dN*/dt=0
N*/N*max = 1-(b/a) |
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Term
| Is the number of species limited be resources the same way that the number of resources limit the number of individuals? |
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Definition
| No this can be expressed in a number of ways. Simberloff came up with 850 case histories of introducing species. Of those 150 caused some harm. Of that 70 went extinct, and of that only 3 were due to interspecific competition. Fossil record supports this as well |
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Term
Apportionment
Annexation
partitioning
Replacement |
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Definition
Species are apportioned among a variety of continents and climate zones. Can change both N* and N*max
Annexation refers to the ability of an organism to develop a key innovation so that organisms can evolove to occupy new environments Can change both N* and N*max
Partitioning refers to the way that ecological interactions can evolve such that a system contains more or fewer species Can chnage N* and N*max
Replacement is niche replacement and therefore N* and N*max stay the same
of all of these only partitioning can be considered a resource based critereon that includes competition |
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Term
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Definition
| The adaptive grid model works as a grid of niches, you insert one or more "founder" species and create a phylogeny in niche space by a simple set of rules. At each turn, every species has defined probability of persisting, or going extinct. if persists it can move or stay, but if it moves into an occupied area it goes extinct. Eventually reaches equilibrium where a=b and matched the logistic growth curve. Can serve as a null hypothesis for analysis of macroevolutionary events |
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Term
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Definition
A compilation of the marine organisms over the past 600 million years shows a patern of increase, stasis and decline involving cambrian, paleozoic, and modern. Each resemble a logisitc curve but wwith increasing N* max, which shows to have resulted from both annexation and partitioning.
number of boxes increased (partitioning) as well as the number of lineages per box demonstrating the annexation. |
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Term
| Three major themes in history of life |
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Definition
1) Episodic but regular increase in the ecological and morphological complexity.
2) succession of major floral and faunal units, the major body types phyla and class appeared early and diversified at lower tax. levels
3) Recurrent meass extinctions which were abiotic and opened up many niches which surviving lineages engaged in a speciation race to vill these vacancies. |
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Term
| Major steps in increasing complexity |
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Definition
| earth originated 4.6 bya, continentd 3.8, rocks with fossils 3.4, aerobic metabolism 2.4. Eukaryotic life evolved around 1.4 with the sybiosis of mito/chloro into prokaryotic organism.This step requires major control mechanisms, by creating a regulatory component of the genome. This was seen as significant because of the new potential for cedllular communication and ultimately multicellular organisms. Coelem evolved about 680 mya and skeletons and shells arose around 600-570 mya. Around 80 phyla arose, including the 31 that survive today. Nothing like that has occurred since |
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Term
| Faunal and Floral succession, winning the speciation race |
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Definition
| Marine fossil record best illustrates the pattern of major successive faunal assemblages. and similar occurs with plants. This succession is step wise increase in the number of habitats and ways of life occupied, and by a corresponding increase in species diversity. The lineages that win do not do so by competitive displacement but rather by speciating and a higher rate, thereby filling up a larger share of the niches that open up as a result of background extinctions. |
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Term
| Species Selection/natural selection |
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Definition
| Process of succession in fauna is analogous to the reproductive success in natural selection, and has been termed "species selection" Both opportunism and adequacy of design play significant roles. |
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Term
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Definition
| The fossil record reveals five events that stand far above backgreound extinction rates since the cambrian time. Each was different in cause and result. Such events vacate vast number of niches, and again it is those survivors that speciate most quickly that will dominate the new equilibrium, usually by diversification at lower levels |
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Term
| Why do large taxonomic divisions rarely originate after the cambrian |
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Definition
| Because mass extinction usually only wipes out one lineage, and all the surviving lineages will fill the gap and create new lower taxonomic groups |
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Term
| Why do annexations occur independently of extinctions? |
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Definition
| Because annexations are a result of genetic mutations that allow for a key innovation. So should occur when species diversity is high (@ equilibrium) instead of after an extinction. |
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Term
| Adaptive radiations and key innovationsd |
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Definition
| Older discussions of AR focus on KI as attributes that confer competitive superiority, and tend to cast AR in terms of the successful usurpation of adaptive space. This is rare however because most radiations follow extinctions without having caused them, and are better viewed as speciation races occuring among survivors of an extinction event. |
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Term
| Second category of radiations |
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Definition
| Second category consists of those that arise from annexation of new space via key innovations. It should be obvious that these events both increase N*max and N*, but without affecting the futures of existing lineages |
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Term
| Functional definition of adaptive radiation |
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Definition
| recognizable only in hindsight, and occur whenever speciation exceeds extinction rates for an applicable period |
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Term
| How can the origin of any specied be described? |
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Definition
| In terms of rates of origin and loss of species. Extinction rates tend to regular within lineages. |
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Term
| Parallel by analogy between natural selection and species selection |
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Definition
| Here "fitness" would be described as relative speciation success, and a fit lineage would speciate faster or display lesser extinction rates. However, is not a cuasual factor in macro. Natural selection does cause microevolution, species selection does not cause macroevolution because micro occurs in a closed set (HW) principal whereas species selection operates in an open set. |
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Term
| How to adequately explain morphogenesis |
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Definition
| Model is required to encompass variation in in timing of gene activity, dosage, and localization. |
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Term
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Definition
| Upstream parts could be altered which could cause large scale disruptions of regulatory pathways, with unpredicatble results. Only way that novel divergent body plans could arise, such as bilateral to radial symmetry. |
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Term
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Definition
| ways that affect rates of cell growth and division |
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Term
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Definition
| alteration in the timing of cell processes. |
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Term
| The five mass extinctions |
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Definition
| Shows five mass extinctions with rate mush higher than background extinction. No phyla went extinct and that only in permian did any classes dissapear. Background extinction rates have also declined. |
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Term
| Three ways How mass extinction can affect diversity |
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Definition
1) By eliminating all members of some lineages while leaving others intact - clade
2) By eliminating most species in some regions or habitats, while not affecting others - bloc
3) A random process - random |
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Term
| examining three ways of mass extinction |
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Definition
| clade and bloc are selective while random is probabilistic. Each would present a different signature in the fossil record. |
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Term
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Definition
| Fossil record shows major increase in morphological complexity and taxonomic diversity at boundary between the vendian and cambrian periods. Evidence from shelled and skeletonized fossils and evidence of bioturbation with soft bodies and coelom. |
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Term
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Definition
| Most diversification in the cambrian occured at the level of major novelties in body plans, corresponding to the appearance of clases and phyla. At the least 31 of the 34 phyla living today. And some 40-70 more which are now extinct |
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Term
| The four major fossil deposits |
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Definition
| All of the deposits illustrate a full range of body plans present in a single site soon after cambrian diversity explosion. |
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Term
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Definition
| For a while many of the fossils of these deposits were shoehorned into still living lineages, and this forced to represent the ancestors of modern groups no matter how poorly they fit. This came from a mistaken view that phylogenitic diversification occured in a gradualistic manner,( v shaped) rather than arising in a short interval (u shaped) Each of the four persistant classes of arthropod are present in burgess shale, but there are over 20 other distinct plans that are not present today |
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Term
| Two types of adaptive radiations |
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Definition
Phylogenetic: spc>>>exn
Ecological: increase diversity |
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Term
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Definition
| Broadly concerned with describing the patterns of higher level regulation of biodiversity accross geeologic time by reference to known process in evolution, ecology and geomorphology. Specific causes of each event are the sums of microevolutionary processes effect on each genotype, summed accross millions of species. Such a statistical and probabilistic approach is acceptable as long as individual cases of events such as speciation or ectinction are numerous and varied. Like how life insurance company makes money betting you won't die based on patterns of sex and age |
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Term
| analyzing mass extinction |
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Definition
| We cannot conclude that mass extinctions are "random events", but rather we can say that clade or bloc effects are not seen, and that the individual causes of extinction were so diverse that a random model would in fact fit. |
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Term
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Definition
models have three desirable properties:
precision, generality, and realism, and that only two can be met at anytime.
H-W is exception. But probabilistic models such as AGM can be general and real but not precise. |
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Term
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Definition
| best two out of three. For a deterministic model the cause and description are the same, but for a probabilistic models a description which may have several outcomes. Works for prob not det. |
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