CH 12-15 BIOLOGY

allopatric speciation

-In allopatric speciation, a barrier physically separates a population into two groups that cannot interbreed. -With no gene transfer between the two populations, each proceeds down its own evolutionary line. -Allopatric speciation can create reproductive barriers. Eventually, genetic differences between the populations give rise to reproductive isolation (either prezygotic or postzygotic).

Modern biologists define species by reproduction

-More recently, the biological species concept defines species based on their potential to interbreed and produce fertile offspring. -New species form when some individuals can no longer interbreed with the rest of the group.

Which of the following must be true for natural selection to occur in an "RNA world"?

-RNA molecules must undergo mutations. -RNA molecules must replicate.

Primates share all of the following characteristics:

-opposable thumbs. -excellent depth perception. -flat fingernails.

A clade is also called a monophyletic group.

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Simple life developed during the Precambrian period, 400 BYA-500 MYA

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You discover that a 24,000 year old fossil has one fourth the concentration of a radioactive isotope compared to a living organism. What is the half-life of this isotope?

12,000 years

Assume that the dominant allele for the D gene occurs at a frequency of 0.8 in a population. What percentage of the populations heterozygous for the D gene, based on Hardy-Weinberg equilibrium?

32%

What is the half life of c14?

5,730 years

Clade

A clade is a group of organisms consisting of a common ancestor and all of its descendants.

Which of the following is an example of a postzygotic reproductive barrier?

A cross between a horse and a donkey produces an infertile mule.

Absolute dating dates fossils using chemistry

A more direct method is to date the fossil itself. One way to do this is radiometric dating: measuring the amount of 14C in a fossil to calculate how long ago the organism died.

Why might speciation occur at an unusually rapid pace?

A new trait adapts a population especially well to its environment, and; The environment changes relatively rapidly, selecting for new traits, and; A dominant group of organisms goes extinct, paving the way for the evolution of new species

Cladistics

A phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxamonys

"Endothermic animals" is a polyphyletic group

A polyphyletic group excludes the most recent common ancestor of its members. Birds and mammals are endotherms, but their common ancestor was not endothermic.

Population bottlenecks cause genetic drift

A population bottleneck occurs if a disaster drastically reduces the size of a population.

What is a vegistal structure?

A vestigial structure has lost its function but is homologous to a functional structure in another species. Vestigial hind limbs in some snake species and pelvises in whales are evidence of these organisms' ancestors

Fraggles are mythical, mouselike creatures that live underground beneath a large vegetable garden. Of the 100 Fraggles in this population, 84 have green fur and 16 have grey fur. A dominant allele F confers green fur, and a recessive allele f confers gray fur. Assuming Hardy-Weinberg equilibrium is operating, -A) What is the frequency of the gray allele f? -B)What is the frequency of the green allele F? -C)How many Fraggles are heterozygotes (Ff)?

A) 0.4 B)0.6 C)48

How do biologists use sequences of proteins and genes to infer evolutionary relationships?

All species use the same four DNA nucleotides and the same 20 amino acids, and many genes and proteins only have minor differences from one species to another. It's unlikely that two unrelated species would evolve precisely the same DNA and protein sequences. Therefore, it is logical to surmise that the greater the molecular similarities, the more closely related the species.

A mountain range separates a population of gorillas. After many generation, the gorillas on different sides of the mountain range cannot produce viable, fertile offspring. What has happened?

Allopatric speciation

Humans evolved from

An ancestor shared with chimpanzees.

A polyploid organism

An organism with more than two sets of homologous chromosomes in its body cells. -A polyploid organism is reproductively isolated from diploids, because the chromosome numbers differ, creating hybrid inviability.

What is a analogous structure?

Anatomical structures are analogous if they are superficially similar but did not derive from a common ancestor

Photosynthesis developed around 3.5 BYA

Bacteria and archaea evolved, which used light for energy and atmospheric CO2 as a carbon source.

What is the most accurate way to explain the relationship between antibiotics and antibiotic-resistant bacteria?

Bacteria with alleles that confer antibiotic resistance are most likely to survive when exposed to antibiotics

Why is multicellularity adaptive?

Cells work together, each specializing in specific functions.

The study of biogeography is most concerned with the _________?

Current and past distribution of species on Earth

Homologous protein sequences demonstrate common descent

Cytochrome c is a mitochondrial protein that is expressed in all eukaryotes. The more amino acid differences between species, the more distant the common ancestor.

Which would be the most useful for comparing ALL known groups of organisms?

DNA encoding ribosomal RNA

cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Why was the Mesozoic era extinction significant to the history of mammals?

Dinosaur extinctions opened up new habitats to mammals.

Why are dinosaurs more closely related to birds than to crocodiles and lizards?

Dinosaurs and birds share the most recent common ancestor.

After an environmental change, foxes with shorter legs than average are most likely to survive and reproduce. What type of selection will act on this population in the coming generations?

Directional selection

Which of the following represents the correct order of appearance, from earliest to most recent?

Ediacarans, fishes, reptiles, flowering plants

Endosymbiosis occurred more than once

Endosymbiont theory proposes that mitochondria and chloroplasts originated as free-living bacteria that were engulfed by other microbes.

Some organelles evolved by endosymbiosis

Endosymbiosis explains the origin of mitochondria and chloroplasts.

Directional selection favors one phenotype over another

Ex: The black moths survive and reproduce more than the light moths.

Stabilizing selection favors intermediate phenotypes

Ex: The medium-sized babies survive and reproduce more than the very large or very small babies.

Disruptive selection favors extreme phenotypes

Ex: Very light and very dark snails both survive and reproduce more than the intermediate colored snails.

The biological species concept defines species based on ______?

External appearance

The biological species concept cannot be applied to ________?

Extinct organisms

Eukaryotes evolved next

Fossil evidence of eukaryotic cells dates to around 1.9-1.4 BYA.

Noncoding DNA mutations can produce new phenotypes

Gene promoter sequences control where and when genes are expressed.

Genetic drift causes evolution to occur

Genetic drift is random sampling error. Allele frequencies can shift dramatically, and often become eliminated, when only part of a population survives to reproduce.

List and describe five mechanisms of evolution

Genetic drift: random loss of alleles in a population Selection: differential survival and reproduction of individuals within a population Mutation: provides the new alleles in a population Sexual selection: individuals with preferred traits are selected for mating and leave more offspring. Migration: moves alleles from one population to another

Scientists use the _______ to divide the history of the Earth into eons and eras. These periods are defined by major geological or biological events, like mass extinctions.

Geologic timescale

Gradualism

Gradualism suggests that evolution proceeds in small, incremental changes

Explain how harmful recessive alleles can persist in populations, even though they prevent homozygous individuals from reproducing.

Harmful recessive alleles can be maintained in heterozygous offspring, especially if heterozygotes have a reproductive edge over homozygous dominant individuals.

Mutations in homeotic genes produce dramatic body structure changes

Homeotic genes help explain how a few key mutations might produce new species

A mule is the offspring of a male donkey and a female horse. Mules are unable to produce offspring. What reproductive barrier separates horses and donkeys?

Hybrid infertility

Why is it important for evolutionary biologists to be able to distinguish between homologous and analogous anatomical structures?

If two structures are termed homologous then there are similarities between them that reflect a common ancestry. Analogous structures appear superficially similar, but the structures have evolved independently.

Explain how understanding evolution is important to medicine, agriculture, and maintaining the diversity of organisms on Earth.

In medicine, evolution is importantto understanding the origin of human disease, to predicting the future of disease, and to promoting the wise use of drugs to prevent and treat disease. In agriculture, evolution is important to predicting which crops will perform best in which areas and to understanding the risk of planting just one type of crop over wide areas. In biodiversity, evolution is important to understanding which areas should be preserved because they arelikely to house the richest variety of species.

Linnaeus and Darwin defined species based on appearance

In the 1700s, Carolus Linnaeus created a naming scheme for species. Each species' name combines the broader classification genus with the term species.

Why was the Miller experiment important?

It demonstrated Earth's early atmosphere could have given rise to organic molecules

The Miller experiment simulated early Earth's atmosphere.

It showed that in a simulated "early Earth" environment, simple molecules can combine into organic compounds.

"how did James Hutton, Georges Cuvier, Georges-Louis Buffon, Jean Baptiste de Lamarck, Charles Lyell, and Thomas Malthus influence Charles Darwin's thinking?"

James Hutton believed that changes in nature are gradual and uniform. Georges Cuviersuggested that after catastrophes species reappear and fossils show extinction. Buffon noted that species change as they migrate to new places from their original location. Lamarck believed environmental forced give birth to new species that come from extinct ones. Lyell was presenting a theory similar to Hutton's that all changes in nature are gradual and uniform. Malthus believed that species produce many offspringand compete for resources.

Fossils found in deeper layers of the earth generally have ______ carbon 14 than fossils found in the upper layers.

Less

Intersexual selection occurs when members of one sex choose mates with the highest quality features.

Like a peacock showing its feathers

How did eukaryotic cells develop compartments?

Many organelles, such as the nucleus, might have resulted from membrane infolding.

What is Absolute Dating?

Method of measuring the age of an object in years by using the radioactive decay and half-life of Uranium and Carbon.

Modern-day organelles developed from ancient bacteria

Mitochondria originated as aerobic bacteria. Chloroplasts originated as photosynthetic bacteria.

Multicellularity developed around 1.2 BYA

Multicellularity was a critical step leading to the evolution of plants, animals, and fungi.

How does the activity of a homeotic gene relate to evolution?

Mutations in homeotic genes can produce new body plans

How does natural selection predict a gradualistic mode of evolution? Does the presence of fossils that are consistent with punctuated equilibrium mean that natural selection does not occur?

Natural selection predicts changes within a species over a long period of time based upon changes in gene frequencies and unequal reproductive success. Punctuated equilibrium does not counter the concept of natural selection; it just means that natural selection occurs more rapidly at some times than at other times

Some genes are more alike between human and chimp than other genes are from person to person. Does this mean that chimps are humans or that humans with different alleles are different species? What other explanation fits the facts?

No. Although chimps and humans share a common ancestor (and therefore share many genes), they are reproductively isolated from one another so they are different species. Genes that are very similar between humans and chimps may be the most important genes (that is, mutations in those genes may be fatal, slowing their rate of change). Genes that vary within a population may not be essential to survival or may have mutated after the two species diverged from the common ancestor.

Place the following events in Earth's history in order. Which happened second?

O2 gas accumulated in the atmosphere

What is the study of fossil remains or other clues to past life. Fossils provided the original evidence for evolution?

Paleontology

A paraphyletic group excludes some of the descendants of an ancestor.

Paraphyletic groups do not consider the last common ancestor.

Phylogenetics

Phylogenetics is the study of evolutionary relationships among species

Punctuated equilibrium

Punctuated equilibrium suggests that the pace of evolution varies -Evidence from the fossil record shows that many animals have evolved in short bursts, in between long periods of little change.

An "RNA world" may have gotten life started

RNA is a self-replicating molecule. Once it formed and replicated, natural selection took over. -Stable molecules that could self-replicate became more common. -The first RNA molecules may have formed on clay surfaces

Relative dating dates fossils according to layer of rock

Relative dating assumes that lower rock layers have older fossils than newer layers. It is indirect, simple, and less precise, but provides valuable information.

Reproductive barriers cause speciation

Reproductive isolation can be either prezygotic(barriers prevent the formation of an embryo) or postzygotic (hybrid individuals have reduced fitness). -Prezygotic reproductive barriers prevent fertilization -Postzygotic reproductive barriers prevent the development of fertile offspring

Sexual selection results from variation in the ability to obtain mates.

Sexual selection results either from competition for access to the other sex (e.g., these rams) or from one sex choosing attractive mates of the other sex.

DNA evidence suggests that modern humans

Share a single origin

microevolution and macroevolution

Small evolutionary changes that accumulate in a population are called microevolution. These can occur quickly, in just a few generations. -Eventually, this leads to macroevolution, which is slower and results from large-scale changes.

Many species look similar as embryos. What causes them to appear different as adults? Why does the study of development give insights into evolutionary relationships?

Species that look similar as embryos may appear different as adults because different parts may or may not develop, or they may develop to a different extent. The study of development is important because it may reveal clues to common descent that are not evident in adult bodies.

Scorpions occupy every continent except Antartica, and all scorpions fluoresce under ultraviolet light. What do these observations most likely suggest about the origin of scorpions fluorescence?

The common ancestor of scorpions fluoresced

The first cells were prokaryotes

The earliest microfossil evidence of prokaryotic cells is from around 3.5 BYA

The first simple cells formed around 4 BYA

The first protocells, self-replicating molecules surrounded by membrane, are similar to prokaryotes.

Sympatric speciation

The formation of new species in populations that live in the same geographic area -Although the habitat may appear uniform, often it consists of many microenvironments that select for different phenotypes. -Sympatric speciation also occurs when gametes unite to form polyploid offspring with more chromosomes than either parent.

Suppose that plants in the San Francisco Bay area and in southern Chile share a common seed dispersal method. Scientists determine that the evolutionary divergence of these plants happened long before this seed dispersal method arose in each plant. What term relates the seed dispersal method of the San Francisco Bay plant to the seed dispersal method of the southern Chile plant? Explain your answer.

The seed dispersal methods are analogous. They provide an example of convergent evolution because the seed dispersal method originated independently after the two plant species shared a common ancestor,

Intrasexual selection occurs in when the stronger individuals in a population battle to win access to mates.

The weaker individuals are denied access.

What characteristic of mitochondria and chloroplasts makes them different from other organelles and suggests they were once independent organisms?

They have their own DNA and ribosomes.

How does variation arise in an asexually reproducing population? A sexually reproducing population?

Variation arises in asexual and sexual species through mutations. In sexually reproducing species, variation spreads rapidly as a result of genetic recombination during meiosis.

Ground beetles have useless hind wings. In related species, the hind wings function in flight. What term describes ground beetles' hind wings?

Vestigial

As Alfred Russel Wallace traveled around the Malay archipelago, he noticed distinct patterns of animal life on either side of an imaginary boundary, which eventually came to be called ________.

Wallace's Line

The founder effect causes genetic drift

When only a few individuals establish a new population, the allele frequency might change. This process illustrates the founder effect.

Flying animals have diverse evolutionary histories. They therefore form _____?

a polyphyletic group

Photosynthetic cells affected early Earth by ______?

adding O2 to the atmosphere.

In population genetics, evolution describes how _________ change from one generation to the next

allele frequencies

Darwin observed that different types of organisms live on either side of a geographical barrier. Such barriers prevent _________?

gene flow

Impact theory

idea that mass extinctions were caused by impacts of extraterrestrial origin -Impact theory suggests that meteorites or comets caused dinosaurs in the Cretaceous period.

What does descent with modification mean?

inherited traits change from generation to generation

Radiometric dating is a type of absolute dating that uses radioactive isotopes which use ______

other isotopes instead of carbon14

parapatric speciation

speciation occurring when two populations have continuous distributions and some phenotypes in that distribution are more favorable than others -Mating can occur between populations, but most individuals mate with their own population. -Parapatric speciation can create reproductive barriers

What is Convergent evolution?

the evolution of similar adaptations in organisms that do not share the same evolutionary lineage

Biogeography

the study of the distribution patterns of species across the planet

Pangea

theory that all continents were all together years ago; because the continents are like a puzzle and fossils have been found in different continents about 225 million years ago

14C decays over time

•Living organisms have a constant amount of 14C in their tissues. •After death, half the 14C is lost every 5,730 years. •In other words, the half-life of 14C is 5,730 years.