What was an alternative explanation and how did the scientists discount it Quizlet

If Darwin had been aware of genes and their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?

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What evidence did scientists use to determine that the 13 species of finches on the Galapagos arose from a single common ancestor?
What keeps different species of finches from mating?
What happened to the average beak depth of finches on the Galápagos Islands after the drought of 1977?
What was the effect of the 1977 drought on the medium ground finch?

If an organism acquires new genes by engulfing, or being infected by, another organism, then a new genetic species will result.
If an organism's somatic cell genes change during its lifetime, making it more fit, then it will be able to pass these genes on to its offspring.
If natural selection can change gene frequency in a population over generations, given enough time and genetic diversity, then natural selection can cause sufficient genetic change to produce new species from old ones.
A single mutation in a single gene in a single gamete, if inherited by future generations, will produce a new species.

Sets with similar terms

The island fox, Urocyon littoralis, is endemic to the Channel Islands, which are located off the coast of southern California. Six of the eight Channel Islands support fox populations, and each of these islands is home to a distinct subspecies, as shown in the table below.
(Look at table)
The island fox shares a common ancestor with the gray fox, Urocyon cinereoargenteus, which is found on the mainland. Both species have similar coloration and a diploid chromosome number of 66. One structural difference between the two species is the reduced size of the island fox, a feature known as dwarfism. The various island subspecies also differ from each other in size, number of tail vertebrae, and other characteristics.
The phylogenetic tree below shows the evolutionary relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate locations on the tree.
First, drag the blue labels onto the blue targets to identify the common ancestors at the branch points.
Next, drag one white label onto the white target to identify the homologous characteristic.
Then, drag one pink label onto the pink target to identify the relationship between the two species.

During the rainy season, and just as the dry season starts, food is abundant for all finches. However, as the dry season wears on, the seeds they eat become harder to find and competition becomes an important factor in survival.
When a serious drought lasting 2.5 years hit Daphne, the only finches that survived were the ones that could find enough food; seeds that they could not split open did not contribute to survival. Heavy mortality in a population means there is strong selection for heritable traits that help individuals survive and reproduce.
For example, G. magnirostris eat large seeds, and G. magnirostris can outcompete all other finches. The Big Birds and G. fortis fight over smaller seeds and water holes, but the Big Birds are dominant to G. fortis because they are almost twice the size of G. fortis.

Given what you know about G. fortis, G. magnirostris, and the Big Bird lineage, what do you predict will happen as the drought continues?

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What evidence did scientists use to determine that the 13 species of finches on the Galapagos arose from a single common ancestor?

Comparisons of DNA sequences revealed the evolutionary relationships among finch species. The data showed that all finch species living in the Galápagos Islands today are more closely related to one another than to any species of birds on the mainland, suggesting that they originated from a common ancestor.

What keeps different species of finches from mating?

Song and appearance both play a role in keeping different species from mating. So when populations of the same species are separated, changes in these traits set the stage for the formation of new species. The Grants have shown that both geography and ecology are keys to the evolution of the Galápagos finches.

What happened to the average beak depth of finches on the Galápagos Islands after the drought of 1977?

Why do you think the average beak depth of the birds increased? Because the drought reduced the number of seeds and finches with bigger beaks were able to eat the larger and harder seeds so more of them survived.

What was the effect of the 1977 drought on the medium ground finch?

Recently they reported a change in the beak size of the medium ground finch on Daphne Major. In 1977 a drought reduced the number of small seeds available for the birds, forcing them to rely on larger seeds requiring considerable force to open.