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77 Cards in this Set
- Front
- Back
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What is adaptation? |
-Adaptation can mean a process or a state -¨The molding by natural selection of a character to perform a function.¨ -Character can be adapted if there is evidence that it evolved for a function/purpose |
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What does function of an organism not explain? |
-The current function does not equal the reason for existance -Function can change throughout time |
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What are two examples of an organism having a character that was created for a different function than what it is currently used for? |
-The ancestors of birds did not evolve feathers to fly, but to regulate body heat -Giraffes do not have long necks for reaching higher leaves. Original reason is uncertain. |
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What is the adaptationist programme? |
-The adaptationist programme is a style of thinking among evolutionary biologists
-Assumes near omnipotence of natural selection -Natural selection forges organic design and fashion the best of all possible worlds |
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What does adaptationist programme do in practice? |
-The adaptationist programme separates an organism, and find the adaptive story about each part -They assume that trade-offs among competing body parts is the only constraint on perfection |
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What are some examples of evolutionary imperfection resulting from trade-offs? |
-Giraffe females incidently obtaining long necks from male genes -Hyena females have pseudo penises which can complicate delivery of pups -Both the Brown Skua and hyena infant females commit siblicide (females having higher levels of testosterone). |
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What are some alternatives to adaptation? |
-Darcy Wentworth Thompson proposed to use mathematics to describe the shapes, chemistry and physics of organisms (allometric growth) |
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What is allometric growth? |
-Allometric growth is the proportioning that helps give its body its specific form -Many similar species have the exact same allometric growth, which can be explained mathematically |
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What is paedomorphosis? |
-Paedomorphosis is when the rate of reproductive development accelerates compared to somatic development -This means sexually active species retain juvenile phenotype, such as axolotl |
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How does pattern formation effect plant and animal mechanisms. |
-Pattern formation in plants and animals have similar spatial organisation of tissues and organs -These mechanisms explain how distantly related organisms can have similar anatomical arrangement |
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How can pattern formation be controlled? |
-Through homeotic genes -Drosophila larvae can have the undeveloped ´leg cells´ taken from one and translated into another -The translantee will grow with an extra developed pair of legs -This can be done with a number of body parts |
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What are hox genes? |
-Hometic genes that provide information on the development of fins in fish and limbs in tetrapods |
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What are the three types of genetic markers? |
1) Chromosomes - the banding pattern on chromosomes is the most commonly used marker 2) Protein polymorphs - electrophoretically detect detectable differences in enzymes are also widely used genetic markers. 3) Microsatellite (nuclear)/Mitochondrial DNA - recently developed and widely used |
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What are the uses of genetic markers? |
-Phylogeny reconstruction -In determination of levels of variation of a pop -To estimate the effects of genetic drift/bottlenecks -To determine levels of relatedness -To detect species |
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What is minisatellite DNA? |
Digested DNA placed on strips, able to compare between parents and offspring. |
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What is the meaning of species? |
-In latin ´kind´ or ´appereance´ -To determine this, scientists compare morphology, physiology and biochemistry |
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What is the biological species concept? |
-The biological species concept states that a species is a group of pops whose members have the potential to interbred and have fertile offspring -Do not breed successfully with other pops -Gene flow between populations holds the phenotype of a pop together |
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What is reproductive isolation? |
-Reproductive isolation is the existence of biological factors that impede two species from producing viable, fertile offspring. -Can be classified by whether factors act before or after fertilisation. |
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What are hybrids? |
-Hybrids are the offsprings of two different species |
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What are the prezygotic barriers of reproductive isolation? |
-Prezygotic barriers block fertilisation from occuring by: -Impeding different species from attempting to mate -Hindering fertilisation if mating is successful |
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What are the habitat isolation barriers of reproductive isolation? |
-Habitat isolation is when two species encounter each other rarely, because they occupy different habitats, even though they are not separated by physical barriers. |
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What are the temporal isolation barriers of reproductive isolation? |
-Temporal isolation occurs when species that breed at different times of day/year/seasons cannot mix their gametes. |
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What is behavioural isolation barriers? |
Behavioural isolation means courtship rituals of one species is unique, and creates a barrier for other species from mating with them (since they cannot perform the ritual). |
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What is mechanical isolation? |
-Mechanical isolation is when morphological differences (physical features) prevent successful mating -An example is with snails who have certain shell orientations, stops successful mating. |
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What is gametic isolation? |
The sperm of one species may not be able to fertilise eggs of another species. |
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What is postzygotic barriers of reproduction isolation? |
Postzygotic barriers prevent the hybrid zygote from developing into a viable, fertile adult: -Reduced hybrid viability/fertility -Hybrid breakdown |
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What does reduced hybrid viability refer to? |
-Reduced hybrid viability means the genes of two different parent species may interact and impair the hybrids development -Hybrids may also be sterile |
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What is hybrid breakdown? |
-Hybrid breakdown is when first-generation are fertile, but when they mate with another species (hybrid or parent), the offspring of the next generation is feeble/sterile |
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What are some limitations of the biological species concept? |
-Many species are physically or ecologically distant but can interbred (grizzly/polar bear hybrids) -The biological species concept cannot be applied to fossils -Can not be applied to asexual organisms (and all prokaryotes) |
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What is the morphological species concept? |
-Morphological species concept can be applied to both sexual and asexual species (unlike reproductive isolation theory) -Relies on subjective critieria -Defines a species by structural features -Requires understanding in morphology to identify homologies, sexual dimorphic organisms, or organisms with complex life cycles |
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What is the ecological species concept? |
-The ecological species concept views a species in terms of its ecological niche -Applies to sexual/asexual species and an emphasis on disruptive selection |
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What is the phylogenetic genetic species concept? |
-The phylogenetic species concept defines a species as the smallest group of individuals on a phylogenetic tree -Emphasis on descent -Applies to sexual/asexual -No clear threshold to what a new species is -Can split species |
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What is the specific mate recognition system? |
-The specific mate recognition system defines a species as a group of organisms that recognise each other as mates -´strucuturally coupled´ -emphasis is on behaviour and role of behaviour in fertilisation |
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What are the properties of the mate recognition system? |
-The mate recognition is mediated by hormones and triggered by external factors -Results in efficient fertilisation -Male/female system operates within a content of various environmental factors -This system is generally stable except during speciation |
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What is speciation and in what ways does it occur? |
-Speciation can take place with or without geographic seperation -Can occur in two ways: -Allopatric speciation -Sympatric speciation |
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What is allopatric speciation? |
-Allopatric speciation is when gene flow between populations is interrupted -When a population is geographically divided into geographically isolated subpops -They evolve individually -If reintroduced, they cannot interbreed |
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What are some properties of allopatric speciation? |
-Seperated pops may evolve independently through mutation, NS and genetic drift -Barriers to reproduction are intrinsic, separation is not a biological barrier |
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What is evidence of allopatric speciation? |
-Regions with many geographic barriers have more species -Reproductive isolation between populations generally increases as the distance between them increases |
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What are the two types of speciation? |
Allotropic speciation Sympatric speciation |
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Sympatric matings - Allopatric matings (AmAf + Bm+Bf) - (AmBf + AfBm) A = population 1 B = Population 2 What value is complete isolation between two populations? What value is non-assortive mating? |
-If a population/gender has a value of 1, it means mating is occurring. -Complete isolation is: (1 + 1) - (0 + 0) = 2 -Non-assortive mating is: (1 + 1) - (1 + 1) = 0 |
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What is sympatric speciation? |
Sympatric speciation is when speciation takes place in geographically overlapping areas |
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What is polyploidy? |
-Polyploidy is the presence of extra sets of chromosomes due to accidents during cell division |
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What is an autopolyploid? |
-An autopolyploid is an individual with more than two chromosomes sets (from one species) |
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What is habitat differentiation? |
-A form of sympatric speciation -Can result in new ecological niches -An example, an animal population eats one plant. A new plant is introduced into the ecosystem, and half the population begins eating that. After enough generations, they cannot eat the others fruit and only reproduce amongst their subpopulation. |
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What is sexual selection? |
-A form of sympatric speciation -Sexual selection can drive sympatic speciation -sexual selection for mates of a different colour has contributed to speciation of cichlid fish in lake victoria |
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What is anallopolyploid? |
-An allopolyploid is a species with multiple sets of chromosomes derived from different species (may only be able to reproduce with other allopolyploids) |
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What is hybridisation? |
When two sister species are reintroduced and produce offspring? |
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What is a hybrid zone? |
The area in which members of different species mate and produce hybrids |
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What are the three possible outcomes when species meet in a hybrid zone? |
-The strengthening of reproductive barriers -The weakening of reproductive barriers -The continued formation of hybrid individuals |
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What process occurs when hybrids are less fit than parent species? |
-Reinforcement of reproductive barriers stop hybrid offspring -Separates parent species further -Eventually stops hybrid offspring from being reproduced |
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What process occurs when hybrids are of equal fitness as parent species? |
-Both parent populations coalesce -Differentiation between parental populations decreases -Substantial gene flow amongst populations -If gene flow is great enough, the two species fuse into one species |
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What process occurs when hybrids are fitter than parental species? |
-Reproductive barriers lower -Formation of new hybrid species |
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At what rate can speciation occur? |
-Can occur slowly or very rapidly -4, 000 years (some cichlids) -40, 000, 000 years (some beetles) -6, 500, 00 years on average |
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How can the rate of speciation be determined? |
-Patterns in speciation can be studied using the: -fossil record -morphological data -molecular data |
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What relationship does macroevolution and speciation have? |
Macroevolution is cumulative effect of speciation and extinction events |
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What is synthetic evolution? |
-Synthetic evolution is the merging of Mendelian genetics and Weissman´s theory -When these theories merged, it changed Darwinism to Synthetic Evolution |
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What is the Linnaean system of taxonomy? |
-The linnaean system distinguishes species based on sameness and differences in morphology. -This reinforces the notion of sameness (genus) and differences (species) |
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What is the Hierarchial Classification system of taxonomy? |
-Linnaeus´ system led to Hierarchial Classification of species -A system for grouping species in increasingly broad categories |
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When naming a species, what are the two criteria? |
The name of the genus first before the species name, then underline or italicize the name. |
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What does a divergence mean in the evolutionary tree? |
-The divergence of two species from a common ancestor -The ¨Deeper¨ the points of separation, the greater the amounts of divergence. |
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What are the two currently used theories in taxonomy? |
-The Phylogenetic Systematics -Cladistics |
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What is Homology? |
When two different species have individually evolved from a common ancestor. |
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What is Analogy? |
-When two morphologically similar species have evolved from two separate common ancestors -They are similar due to being driven by similar environmental factors |
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What is a Taxon? |
A Taxon is a species at the top of a phylogenetic tree |
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What is a clade? |
A clade is a group of taxons (species) at the top of a phylogenetic tree |
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What is a phylogenetic tree? |
-A phylogenetic tree is a diagram like a tree. -The branches represent the evolutionary lineages -It shows the common descent of species in the higher taxa. |
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What is a cladogram? |
-a ¨Nested hierarchy of taxa¨links several species of animals together based on morphological similarities -Usually an outlier species outside the clade for comparison -Ie Bass, Lizards, Horses and Monkeys all have vertebrae/jaws, -Octopodes do not and are outliers |
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What can be inferred using a cladogram? |
-Using a clade to determine the morphological chatacteristics of species, we can determine what the character the common ancestor might have had -We can also determine what the common ancestor did not have from the outlier group in the cladogram |
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What is the difference from species at the top and at the bottom of a cladogram/phylogenetic trees? |
-Species at the top of the tree are more derived |
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What makes a taxon monophyletic? |
A taxon is monophyletic if it includes the most recent common ancestor, all members of that group, and the most derived descendants. Common ancestor>members of group>all derived descendants (alive today) |
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What makes a taxon paraphylitic? |
A taxon is paraphyletic if it includes the most recent common ancestor of all members of a group, but not all descendants of that ancestor. Common ancestor>members of group>not all derived descendants |
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What makes a taxon polyphyletic? |
A taxon is polyphyletic if it does not include most recently common ancestor of all members of a group No common ancestor>not all members of group>not all derived descendants |
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What are the two principles of traditional evolutionary taxonomy? |
1) Common descent 2) Amount of adaptive change -Evolutionary taxa must have a single evolutionary origin and must show unique adaptive featuers |
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What did George Gaylord Simpson argue about the evolutionary tree? |
-A higher taxon on the evolutionary tree should be given a higher status if it represents an adaptive zone |
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What are adaptive zones? |
-Adaptive zones are places in the evolutionary tree that tends to have a faster rate of evolution, like the penguin branch in the bird tree -Or humans in the great age tree |
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What are the differences of identifying species in biology and taxonomy? |
-In biology, a species is a self-defining natural group -In taxonomy, a species is a taxon like all others in its genus/genus/family, etc |
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What is the use of barcoding? |
-Barcoding allows us to compare DNA from two organisms and determine the level of difference (and figure out the level of speciation) |
