Which of these phenomena does NOT illustrate the principle of gradualism? Select one:a.At a digging site, scientists discover hundreds of years of buried fossils of birds with short, curved beaks. Directly underneath those fossils, the scientists find hundreds of years of fossils of the same bird, but with long, straight beaks.b.During the Early Eocene period, species of horses arose and slowly developed over time.c.Fossil records of land plants show that angiosperm seeds evolved about 380 million years ago, the vascular tissue about 409 million years ago, and multicellular gametangia and cuticles about 425 million years ago.d.Based on the evidence in the fossil record, scientists determined that the average tail fin length of members of a particular fish species increased by approximately one centimeter every 20 years.

Two scientists studied patterns of evolution in the fossil record. Many species they analyzed showed periods of slow changes interrupted by a period of rapid change. This pattern of periods of slow change interrupted by periods of rapid change with few, if any transitional fossils, best describes thetheory of —Ask Studybuddy (Login to use)Group of answer choicesGene FlowNatural SelectionGenetic DriftPunctuated Equilibrium

Between the Middle Jurassic and Holocene, birds evolved an enormous diversity of behaviours. The distribution and antiquity of these behaviours is difficult to establish given a relatively poor fossil record. Rare crop, stomach and gut contents typically reveal diets consistent with morphology but stem-members of some lineages (including Cariamae and Coraciiformes) seem to have been different in ecology from their extant relatives. Most of our ideas about the behaviour of fossil birds are based on analogy (with skull form, limb proportions and claw curvature being used to guide hypotheses). However, this has limitations given that some extinct taxa lack extant analogues and that some extant taxa do not behave as predicted by osteology. Reductionist methods have been used to test predation style and running ability in fossil taxa including moa, Gastornis and phorusrhacids. Virtually nothing is known of nesting and nest-building behaviour but colonial nesting is known from the Cretaceous onwards. Rare vegetative nests demonstrate modern nest-building from the Eocene onwards. Ornamental rectrices indicate that sexually driven display drove some aspects of feather evolution and evidence for loud vocal behaviour and intraspecific combat is known for some taxa.Consider each of the choices separately and select all that apply.From the information in the passage, which of the following could be a problem associated with learning about primitive birds using their fossil remains?The fossils are often in a decrepit state, and so do not provide an accurate representation of the actual physical traits of the birdsSome of the birds whose fossils are being studied do not have any related species in modern times to compare the fossils withThe fossils do not provide any information about the diets or nesting behaviour of primitive birds

Scientists have discovered several fossils ranging from 2 to 9 million years old that they believe to be ancestors of a present-day crustacean species. Other than differences in overall size, the fossils appear to be almost structurally identical to the living species. Which of the statements is the MOST reasonable explanation for this observation?Select one:a.The fossils found are not as old as scientists believe them to be.b.The fossils and present‑day crustacean species are an example of convergent evolution.c.Stasis is occurring in this crustacean species.d.Structural features cannot be accurately identified in fossils.

Evolution is usually a ________, ___________ processLong, gradualShort, quickSubmit

Darwin's theory of natural selection has long been a guiding light for explaining changes in species over time. These changes happen for a number of reasons and are usually based on selective pressure.Which of the following examples is NOT an instance of natural selection?Elimination ToolSelect one answerAA group of giraffes stretching their necks in order to reach more leaves to eat.BA shift in the coloring of beetles over time to blend in with the leaves.CMore nocturnal mice in an area over time due to the presence of daytime predators.DA group of gophers getting smaller over time because they can hide in caves from predators.