BIO macroevolution and human evolution (ch 2, 6, 7) + ecology definitions
Terms in this set (79)
Cells interact continuously by means of (blank) during development
cell to cell signals
what does it mean to say that differentiation is "progressive"
cells become increasingly more specialized over time
what is a homeotic mutant
an individual with a structure located in the wrong place
what is homeosis
replacement of one structure by another structure (a structure develops in the wrong location)
why is it significant that many of the genes involves in development encode regulatory TFs
differentiation depends on changes in gene expression. changes in gene expression depends on differences in regulatory transcription factors.
explain the connection between the existence of regulatory cascades and the observation that differentiation is a step-by-step process
differentiation is triggered by the presence or absence of external signals. these signals trigger the production of transcription factors, which induce other transcription factors, and so on - a sequence that constitutes a regulatory cascade - as development progresses. at each step in the cascade, a new subset of genes is activated - resulting in a step-by-step progression from undifferentiated to fully differentiated cells
fruit flies have 6 legs, spiders have 8 legs, centipedes have many, earthworms have none. all of these spp are segmented and have Hox genes. based on data in this chapter, generate a hypothesis to explain how variation in leg number evolved in the species
homeotic genes such as hox genes are responsible for triggering the production of structures like wings or legs in particular segments. one hypothesis to explain the variation is that changes in gene expression led to different numbers of segments that express leg-forming hox genes
in 1992, david aux and colleagues used genetic engineering tech to introduce an active human gene for a protein that inhibits apoptosis into embryos of the roundworm C. elegant. when the team examined the embryos, they found that cells that normally undergo programmed cell death survived. what's the significance of this observation?
the result means that the human gene can be transcribed in worms and that its protein product has performed the same function in worms as in humans. this is strong evidence that the genes are homologous, and that their function has been evolutionary conserved
mutations in genes responsible for development may lead to
evolution of new body sizes, shapes and structures
what happens if the cell-cell signals, TFs, and regulatory DNA sequences that are active in development undergo mutation
if the cell-cell signals, TFs, and regulatory DNA sequences that are active in development undergo mutation then the adult phenotype is likely to change as a result. variation in phenotypes due to genetic changes is the basis of evolutionary change
you be able to explain the evidence behind the claim that changes in cell-cell signals and TFs were responsible for the loss of limbs in snakes
when patterns of expression of 2 key genes involved in limb versus rib formation are compared in chick and snake embryos, they differ. in snakes, the "form ribs here" pattern occurs instead of the "form legs here" pattern
these are a major pattern in the history of life; they are instances of rapid diversification associated with new ecological opportunities and new morphological innovations
(blank) and (blank) occur rapidly during an adaptive radiation, as a single lineages diversifies into a wide variety of ecological toles
speciation events, morphological change
(blank) can be triggered by ecological opportunity - for example, the colonization of a new habitat that offers resources but lacks competitors
(blank) can be triggered by morphological innovations such as limbs, flowers and feathers, if the structure allows individuals to exploit resources more efficiently or in a new way
you should be able to explain why the evolution of animals that could move throughout marine environments - not just in benthic habitats - created ecological opportunity
they could eat food that was available off the substrate. and once animals lived off the bottom, it created an opportunity for other animals who could eat them to evolve.
you should be able to evaluate whether environment changes caused by humans are eliminating species in a rapid manner, as opposed to those spp being poorly adapted to their environment
human-induced extinctions today are not due to poor adaptation to the normal environment. humans are changing habitats rapidly and in unusual ways, so it is not possible for most species to adapt to these changes rapidly enough to avoid extinction
these have occurred repeatedly throughout the history of life; they are environmental catastrophes that rapidly eliminate most of the spp alive
a single lineage diversifies rapidly, and descent populations occupy many habitats and ecological roles
the initial diversification of animals took place over some 50 million years, at the start of Cambrian period, why is the diversification called an explosion
diverse animal forms are found in the cambrian that are not present in earlier strata. an enormous amount of diversity appeared in a time frame that was short compared to the sweep of earlier earth history.
give an e.g. of an adaptive radiation that occurred after a colonization event and after a morphological innovation. in each case, provide a hypothesis to explain why the adaptive radiation occurred
adaptive radiation of Anolis lizards after they colonized new islands in the Caribbean. hypothesis: after lizards arrive on each new island where there were no predators or competitors, they rapidly diversified to occupy 4 distinct types of habitats on each island. adaptive radiation during the Cambrian period following a morphological innovation. hypothesis: additional Hox genes made it possible to organize a large, complex body; the evolution of complex mouthparts and limbs made it possible for animals to move and find food in new ways
what's the diagnostic traits of vertebrates
vertebrae and a cranium
why are pharyngeal jaws found in many ray finned fishes important?
they help process food
whats the relationship between the dorsal hollow nerve cord and the spinal cord
the spinal cord is a type of dorsal hollow nerve cord
the cells that made up jaws and gill arches are derived from the same population of embryonic cells. why does this observation support the hypothesis that jaws evolved from gill arches in fish
if jaws derived forms of gill arches, then the same cells should be involved in the development of the jaw and the gill arches
describe the genetic evidence that supports the hypothesis that the tetrapod limb evolved from the fins of fishes
homologous regulatory proteins are involved in the development of the fish fins and the upper parts of mammalian limbs, supporting fish-to-limbs hypothesis
Homosapiens is the sole survivor of an adaptive radiation that took over the past 7 million years?
the hominins fulfill the criteria for an adaptive radiation over a short time interval, many species that occupy an array of foods and habitats evolved. changes in tooth and jaw structure, tool use, and body size suggest that different hominin species exploited different types of food
explain how the evolution of the placenta and lactation in mammals improved the probability that their offspring would survive compared to species without prenatal care
increased prenatal care allows offspring to be better developed, and thus have increased chances of survival, before they have to live on their own
when feathers first evolved, did they function in flight?
no most of the feathered dinosaurs known from fossils did not fly, the first feathers may have functioned in display or as insulation.
mamals and birds are endothermic. did they inherit this trait from a common ancestor, or did endothermy evolve independently in these 2 lineages?
endothermy evolved independently in the 2 lineages. birds are a highly derived lineage of reptiles, and most reptiles aren't endothermic, so we can infer that the common ancestor of birds and mammals was also not endothermic
evolutionary developmental biology ('evo-devo'),
one of the cartilaginous or bony elements that form the spine of vertebrate animals
a bony, cartilaginous, or fibrous case that encloses and protects the brain of vertebrates; forms part of the skull),
(a type of vertebrate connective tissue that consists of relatively few cells scattered in a stiff matric of polysaccharides and protein fibres),
any member of the taxon that includes all vertebrates with 2 pairs of limbs)
in aquatic vertebrates, a curved region of tissue between the gills, gills are suspended from these
a secondary jaw in the back of the mouth, found in some fish, derived from modified gill arches
duration of embryonic development from fertilization to birth in those species that have live birth)
any action by which an animal expends energy or assumes risks to benefit its offspring - e.g. nest building, feeding of young, defence
(one of the 2 major lineages of primates, including lemurs, tarsiers, pottos and lorises),
(one of the 2 major lineages of primates, including apes, humans and all monkeys), ,
(the lineage of mammals that includes prosimians (lemus, lorisies, etc), monkeys and great apes) hominids (includes humans and extinct related forms, chimps, gorillas, and orangutans; distinguished by large body size, no tail and an exceptionally large brain),
humans and extinct related forms; species in the lineage that branched off from chimps and eventually lead to humans
(walking primarily on 2 legs),
a bony, cartilaginous, or fibrous case that encloses and protects the brain of vertebrates; forms part of the skull
a pre-historic European population of modern humans known from fossils, paintings, etc
a recently extinct European species of hominid, closely related but distinct from modern humans
(says that modern humans evolved in Africa and spread to other continents, replacing other homosapiens without interbreeding with them
• mitochondrial DNA (mtDNA) ,
Y chromosome DNA,
fine niche hypothesis.
• organismal vs. population vs. community vs. ecosystem ecology,
abiotic vs. biotic (identify and provide an example of an abiotic and a biotic factor),
abiotic means no alive (e.g. air, water, and soil); biotic means living or produced by a living organism
the effort to study, preserve, and restore threatened populations, communities, and ecosystems
the movement of individuals from their place of origin (birth and hatching) to a new location
invasive vs. exotic species.
why is reinforcement an appropriate name for the concept of natural selection should favour divergence and genetic isolation if populations experience post zygotic isolation
it reinforces selection for divergence that began when the species were geographically isolated
the biological species concept can be applied to only to which of the following groups (bird species living today, dinos, bacteria, archaea)
bird species living today
ACNS1 a large amount of gene flow is now occurrring among human populations due to intermarriage among people from different ethnic groups and regions of the world. is this phenomenon increasing racial differences in our species?
decreasing. gene flow tends to equalize allele frequencies among populations
what's the world went to hell hypothesis for the end permianian extinction? what underlying mechanism is responsible?
environments all over the world deteriorated rapidly - large parts of the ocean lacked oxygen, many coastal habitats disappeared due to change in sea level, and little oxygen was available in the atmosphere. the underlying cause of these changes is unknown
why are monophyletic groups identified by shared, derived traits?
if a trait evolved in a common ancestor, then all of its descendants should share that trait, unless its lost
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