Posted Flashcards
(31 cards)
Active extinction
- when a species is driven towards extinction by direct competition with another species
- word cloud: competition, adaptation, natural selection
example: multituberculates were a species very similar to rodents. They reached peak population in the Paleocene Era. Rodents first appeared at that time, and quickly outcompeted Multituberculates - who went extinct in the Oligocene.
Allopatry
- When a population or species are geographically isolated from each other, resulting in little to no gene flow between them and separate evolution over time.
Word Cloud: reproductive isolation, gene flow, geographic isolation, speciation
Example: Flowing river acts as a barrier to movement. No ene flow between the populations results in evolutionary independence.
Background Extinction
- the amount of extinction that commonly occurs or is considered to be relatively “normal” due to evolutionary processes. This is different from mass extinction, because it is not a large event, but gradual change.
Word Cloud: ecosystem changes, gradual, adaptations, competition
Example: the dodo bird is a population that lives in an area where they had no natural predators and thrived. There was later an introduction of predators and competition when humans discovered them in the 1500s and this led to their extinction due to changing environment (not a mass extinction event).
Biotic Factors (extinction)
- organisms within an ecosystem that play a large role in interacting with and influencing other organisms and their environment
- (extinction): in all ecosystems, there is a balance between all the organisms. If there is overconsumption of resources and over dominance of one species, it can lead to extinction of others
Word Cloud: living orgs, competition, ecosystem interactions
Example: the availability of food resources for frogs (dragonflies) is depleted overtime
Competitive Displacement
- occurs when two species are competing for resources and one outcompetes the other, leading to the extinction of the ‘loser’ species.
Word cloud: extinction, resources, interspecific competition
Example: European starlings outcompeting other native birds for food resources at the bird feeder; if the native bird ends up extinct, it becomes an example of competitive displacement!
Cospeciation
- occurs when two species evolve in response to each other; a good indication that cospeciation has occurred is congruent phylogenies
Word cloud: parasite/host, predator/prey, convergent evolution, congruent phylogeny
Example: the speciation events of each species is directly correlated to the species that it is in cospeciation with (cladogram branching, traits developed over time)
Diffuse Coevolution
- an evolutionary process where a species evolves in response to several species, rather than to a single species
Word cloud: selection pressure, multiple species, mutalism
Example: the purple flower has evolved red coloration as an adaptation to appeal to a broader range of pollinators in its environment
Ecological speciation
- a form of reproductive isolation driven by natural selection, where different ecological factors act differently on two populations
Word cloud: new environment, standing genetic variation, reproductive isolation
Example: threespine sticklebacks exhibit a loss of body armour and body size when there is movement from a marine to a freshwater environment. These are adaptations that a driven by environmental pressures, a key mechanism of ecological speciation
Evolutionary Species Concept
- Represents a species lineage start and
end to outline a specific species in the fossil
record
Word Cloud: Asexual/Sexual, Lineage, Fossil record, Define
example: independently evolving
lineages with their own
reproductive isolation, lastly
specific outlined start and
end are present.
Gene flow
the transfer of genetic info between populations; intro of new alleles
Word Cloud: hybridization, maintains genetic diversity, block to gene flow = reproductive isolation
Example: populations that cross paths during breeding season
Host-parasite interactions
- Parasites and their hosts can continually coevolve with each other. The host becomes resistant to the parasite and the parasite
becomes better at using the host.
Word Cloud: virulence, horizontal/ vertical transmittance, coevolution
Incumbent Replacement
- A well-adapted species becomes
extinct and is replaced by a new
species that is able to diversify.
Word Cloud: diversify, shift, passive
Example: -Dinosaurs were the incumbent species (well-adapted and diverse) which
prevented mammals being able to diversify and grow. When dinosaurs became extinct, it gave mammals an opportunity to diversify to
what it is today.
Mass Extinction
- A statistically significant increase above
background extinction rate. There have been five mass extinction events in Earth’s
history: (1) End Ordovician, (2) Late Devonian, (3) End Permian, (4) End Triassic, and (5) End Cretaceous.A mass extinction occurs when there is a loss of at least 75% of species within two million years.
Word Cloud: background extinction, abiotic, biotic
Example: out of four species, only 1 survived the mass extinction after ~2my.
Mutation Order Speciation
- the mutations fixed in one population are
incompatible with those in other populations because they benefit each species in different ways
-More prevalent in smaller populations
-BDM Model of Incompatibilities
Word Cloud: allopatric, reproductive, ecological, speciation, isolation, sympatric
Example: mutations represented in populations cannot intermix.
Mutualism
a symbiotic relation in which two species benefits by their interaction
Word cloud: beneficial, symbiotic, coevolution, relationship
Example: one species of moth is only moth with long enough tongue to pollinate long nectar tube of flower
Oscillation
- Two species with an antagonistic relationship will alternately evolve, with dominance switching back and forth
between them
Word Cloud: Co-evolution, Red Queen Hypothesis, Evolutionary arms race
Example: A bug evolves to eat a poisonous plant, and the plant in return increases the toxicity to make it unavailable; this cycle will continue to repeat
Parapatry
A type of speciation where there
is no physical barrier, but a
change in the geographical space
Word Cloud: disjunct, separated, geographical differences
Peripatry
- When rare alleles are fixed in a small population - after the drift of a few individuals – leading to speciation.
Word cloud: founder affect, reproductive solation, genetic drift, speciation
Example: When a small groups leaves the populations, the population becomes so genetically different, no allowing the small group to rejoin and become one
Phylogenetic species concept
- a cluster of organisms that is distinct from other such as clusters, and within which there is a parental pattern of ancestry and descent
Word cloud: subspecies, DNA evidence, Tip Taxon, Geographic isolation
Example: phylogenetic tree/taxonomy visuals
Postzygotic isolating Factor
- A reproductive barriers that occurs
after fertilization, preventing the formation of
surviving, fertile offspring between two different species. These barriers occur after the zygote is formed and lower the reproductive success of hybrids by causing them to either die early, or have offspring that are weak or infertile
Word cloud: fitness, offspring, gene flow incompatible
Example: Horse + donkey = infertile mule due to chromosome distribution
Predator-Prey Interactions
The interaction between a predator and prey where the predator eats the prey for survival. This can lead to coevolution that drives the evolution of both species. An example of this interaction is monarch butterflies and birds.
Word cloud: coevolution, predation, food chain
Example: constant change results in changing populations due to development and competition to survive
Prezygotic isolating Factor
A prezygotic isolation factor is a method of
reproductive isolation that prevents individuals of different species from reproducing, leading to speciation. This isolation takes place before gamete fertilization and includes five different types of isolation: mechanical, temporal, behavioral,
habitat, and gametic.
Word cloud: speciation, gamete fertilization, mating, sexual reproduction
Example of prezygotic mechanical mechanism
A dog and a cat have differently sized structural parts, not allowing them to mate
Example of prezygotic Behavioral Factor
Birds having different songs to vocalize with one another keeps them within their species
