species and speciation Flashcards
what is a nested hierarchy of life?
made by carl linnaeus
its a way to identify how species relate to each other
categorized based on similar traits
starts broad and get more specific
what is a species?
group of organisms that are biologically distinct from other and evolving along lineages
what is a species concept?
a set of conditions that are necessary and sufficient to identify a group of individuals as a species
don’t only define what a species is but also define what speciation is
what is morphological species concept?
all individuals of a species share measurable traits that distinguish them from individuals of other species
based on notable differences in phenotype
what are the pros for morphological species concept?
a practical approach that everyone understands
focuses on novelties that have arisen over time
used for classifying fossil records
not focusing on selection and evolution
what are the cons of morphological species concept?
not useful where species exhibit substantial phenotypic polymorphism or belong to rings
not useful when there is lots of superficial phenotypic differences between putative species/groups
what is biological species concept?
based in the ability of populations to interbreed and produce viable offspring
under natural conditions
what are the pros for biological speciation?
many sister species are hard to distinguish
uses own perceptions to set limits
key unit of evolutionary change and that gene flow is the glue that holds species together
studies reasons that underlie reproductive isolation
what are the cons for biological species concept?
can only be used for living populations, no temporal dimensions relies on sexual reproduction
populations/species near each other can mate
doesn’t apply to organisms created by hybridization
what are pre zygotic isolating mechanisms?
temporal, ecological, behavioural, mechanical and gamete mortality
acts prior to the production of a zygote (fertilized egg)
what are post zygotic isolating mechanisms?
hybrid inviability and hybrid sterility
acts after the zygote formation
what are subspecies?
a taxonomic subdivision of a species
what is a species ring?
a species with a geographic distribution that forms a ring around uninhabitable terrain
what is a cline?
a pattern of smooth variation in a characteristic along a geographic gradient
what is sexual reproduction?
gametes from mother and father are passed to offspring
what is parthenogenesis?
only passes genes to daughter and nothing else, no male needed
what is hybridogenesis?
passes on what gamete they got from their mom and pairs it with a male gamete
same mother gamete is passed on
what is gynogenesis?
copying entire genome and passing it on to offspring, no male gamete in offspring’s genome
male gamete only triggers the copying of the genome
what is a reproductive isolating mechanism?
biological characteristic that prevents the gene pool of 2 species from mixing
what is a hybrid?
an organism produced by mating between parents of different species or sub species
what is ecological isolation?
prezygotic isolating mechanism
species live in same geographical region occupy different habitats
what is temporal isolation
pre zygotic isolating mechanism
live in same habitat but breed at different times of day or different times of year
what is biological isolation?
prezygotic isolating mechanism
nonliving tissues between the vascular cambium and the stem surface
signals of one species isn’t recognized by the other
what is mechanical isolation?
prezygotic isolation
differences in the structure of reproductive organs or other body parts
what is gametic isolation?
prezygotic isolation
incompatibility between the sperm of one species and the eggs of another; may prevent fertilization
what is hybrid inviability?
postzygotic isolating mechanism
hybrid individual has low probability of survival to reproductive age
what is hybrid sterility?
postzygotic isolating mechanism
hybrid offspring cannot form functional gametes