Ascientist is studying the fossil record to construct an evolutionary lineage for an order of fishes. the scientist proposes that the lineage involves long periods of little change to species and then brief periods of significant changes. is the scientist’s proposal consistent with modern evolutionary theory?

a) yes, the scientist is describing a pattern of punctuated equilibrium
b) yes, but only if the brief periods of significant changes occurred after mass extinctions.
c) no, species evolve only gradually and at a relatively constant rate of change.
d) no, species evolve only gradually, although the rate of change may vary among evolutionary lineages.

Correct A. Punctuated equilibrium is an evolutionary theory that suggests that species remain stable/somewhat unchanging throughout most of their existence and go through rapid changes in relatively short periods. This rapid change in the species' traits is typically attributed to geologic events (ex: mountain range forming and separating 2 populations of the same species, which would lead to different selective pressures on either side of the mountain and changes in the traits of the two populations).

Incorrect Answers:

B. Mass extinctions might be a good explanation for significant changes in a species in a brief period of time (if the species was one of the species to survive the extinction), but this is definitely not the ONLY explanation for such changes in a population.

C. There are theories that suggest a gradual and relatively constant change in species throughout their existence, but there is more evidence (especially in the fossil record) and support for punctuated equilibrium.

D. ***same explanation as C***

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

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