Week 11 SmartBook Evolution and Speciation

Economically important organisms that have been modified significantly through artificial selection include

Cattle, pigs, crops

In the early 1850s, scientists noticed that the frequency of light colored peppered moths in polluted areas

Decreased

Adaptive radiation

Galápagos finches supposedly underwent a(n) ______ after an ancestral population arrived on the islands about 2 million years ago and eventually evolved into a cluster of 14 species with different feeding adaptations.

Convergent Evolution

Happens when natural selection appears to have favored parallel adaptations in unrelated organisms that live in similar environments.

Artificial selection

Humans choose the parents of the next generation

Evolution by natural selection requires that variation exists for a trait, the variation in the trait leads to differential reproductive success, and that the variation

Is heritable.

Embryological Development

One of the strongest lines of anatomical evidence of evolution that are common to a group of related organisms.

Modern Horses Vs Early Horses

One toe vs 4 in front, 3 in back

Necessary components for Species Concept

Organisms are distinct in one location, and populations of those organisms are reproductively connected by the breeding of individuals. Connections between different populations of the same species

Natural selection

Organisms that survive and reproduce are those that pass their genes on.

Light, and Black

Peppered moths come in a variety of shades, from light gray with speckles to completely black, (melanic).

Why does polyploidy lead to sympatric speciation?

Polyploid individuals cannot mate with normal diploid individuals.

Character displacement

Process in which natural selection favors individuals with traits that allow them to use resources differently than other individuals, and over time the species diverges in phenotype and resource use.

Process of Relative Dating

Rocks are dated by their relative position, rocks in deeper strata being generally older.

Sympatric Species

Species that are species can occur in the same location and are phenotypically different.

Homologous Structures

Structures in different species that are similar because of common ancestry.

Prior to 1850, the melanic form of the peppered moth in Europe was

Very rare

Natural Selection

considered by scientists to be primarily responsible for evolution

Direct Evidence

evolution proof provided by fossils

Postzygotic isolating

A type of reproductive isolation in which zygotes are produced but are unable to develop into reproducing adults; these mechanisms may range from inevitability of zygotes or embryos to adults that are sterile. Although fertilization is successful, the resulting hybrid is unable to reproduce.

Postzygotic Isolating

A type of reproductive isolation in which zygotes are produced but are unable to develop into reproducing adults; these mechanisms may range from unviability of zygotes or embryos to adults that are sterile.

Provide molecular evidence of evolution

All animals possess similar pattern formation genes. Color vision genes are similar among relatives of humans.

Vestigial structures.

Anatomical features that have no apparent function but resemble structures of presumed ancestors

Even though humans have used artificial selection for centuries, only animals have been significantly modified by our efforts.

FALSE: there are many types of organisms that have been modified by artificial selection, including many plants such as corn, strawberries, etc.

Differences in their feeding habits

Finches on the Galapagos islands exhibit remarkable variation in the shape of their beaks. What best explains this variation?

Why does Geographic isolation accelerates speciation?

It restricts gene flow

Hybridization in natural settings

Left unexplained by the biological species concept, thereby weakening the concept?

Polyploidy

Mechanism that can cause immediate reproductive isolation and lead to sympatric speciation

Early horses had four toes on the front feet and three toes on the hind feet, all encased in fleshy pads. What statement correctly describes how the toes have changed during the evolution of modern horses?

Modern horses have a single toe enclosed in a bony hoof.

If reproductive isolation is the criterion used to define species, then the process of speciation is equivalent to

The evolution of reproductive isolating mechanisms

The not uncommon occurrence in natural settings of which of the following weakens the biological species concept

The not uncommon occurrence in natural settings

Adaptive Radiation

The phenomenon in which a cluster of species evolves to occupy several different niches within a region

Ecological Isolation

The reproductive isolating mechanism that occurs when the ranges of two species overlap, but they rarely come into contact with one another because they utilize different habitats

Biogeography

The study of where organisms live now and where they and their ancestors lived in the past

Conditions that scientists must demonstrate are occurring in studies of natural selection in action. The variation must be genetically transmissible. There must be variation in the population for the trait being examined. The variation must lead to differences among individuals that affect reproductive success.

The variation must be genetically transmissible. There must be variation in the population for the trait being examined. The variation must lead to differences among individuals that affect reproductive success.

Because changes in traits are due to changes in alleles of a gene, the more distantly related two organisms are,

the more different they are molecularly.