Bio 9/27

How can a new species arise through isolation?

2 or more species can rise from one current species in the final stage of speciation (reproductive isolation)

What sort of time span can be measured using radiometric dating techniques?

A geologic time span such as hundreds of thousands of years.

What is shown in a phenotypic distribution?

A graph of the phenotypes for a certain trait of a population

Fossils that record the ________________ of an organism. Examples include nests, burrows, imprints of leaves, and footprints.

Activity

Relate adaptations and evolution?

Adaptation is what caused evolution because animals slowly adapted to the environment and evolved into a different-looking animal. For example, giraffes used to be a lot shorter, but they adapted to the environment (which contained taller trees) and grew taller, which is another example of how evolution occurs.

Relate population and variation?

All populations experience variation. Just like how not all humans look alike yet belong to the same species, all other populations contain animals of the same species that differ which creates variation (example: Golden Retrievers and Chihuahuas).

The Meteorite Hypothesis showed that 19 _____ found in a meteorite that fell near Murchison, Australia in 1969 are found in other places on Earth

Amino acids

Relate analogous structures and vestigial structures?

Analogous structures and vestigial structures are both structures that show similarity between different species. Vestigial structures show similarity by origin of that structure (like a common ancestor), whereas analogous structures share a common function yet don't have any relation (like a bat's wing and a fly's wing).

Occurs between populations with different mating or courtship rituals

Behavioral isolation

Thomas Malthus was an economist who proposed that resources such as food, water, and shelter are natural limits to human population growth. Explain how Darwin extended this idea in his theory of natural selection.

Darwin expanded on Malthus's proposition by creating the theory of natural selection, reasoning that since a limited food supply limits the population, other factors probably do the same in nature, which acts as the "selective agent" in his theory of natural selection.

What insights did Darwin gain from observing island organisms such as the Galápagos tortoises and finches?

Darwin observed that animals of the same species varied in different aspects that appeared suited to their environment. Tortoises that lived in areas with taller plants had longer necks than those that lived in areas with shorter plants, which shows how tortoises adapted to fit their environments.

On his voyage, Darwin found fossils of extinct organisms that resembled living organisms and shells of marine organisms high up in the mountains. How did these observations provide evidence that Earth is very old?

Darwin's observations of marine fossils that resembled living organisms in the mountains show that the Earth is very old because it reveals that that mountain must have been under water at one time, which proves that the Earth has evolved very much since that time.

The geologic time scale represents the history of

Earth

Most scientists believe that

Earth is billions of years old

The smallest unit of geologic time

Epoch

The smallest units of geologic time are known as

Epochs

Consists of two or more periods

Era

All cells in multicellular organisms today are ______.

Eukaryotic

__________________ cells arose about 1.5 billion years ago

Eukaryotic

The best index fossils are those that are common, easy to identify and find, and that...

Existed only for a short period of time

The turkey vulture and the California condor both feed upon dead animals, known as carrion. Neither species of bird has feathers on its head. Explain how natural selection may have played a role in the feather- less heads of these carrion eaters.

Feathers on their heads could make them more susceptible to disease from the dead animals, so they acquired the beneficial trait of featherless heads to avoid disease and survive.

Eon name:

Hadean

Occurs when there are no changes in allele frequency from one generation to the next, almost impossible in nature

Hardy Weinberg Equilibrium

Why is heritability important for both natural and artificial selection?

Heritability is important for both natural and artificial selection because without the ability to inherit traits, the traits that a breeder wants another animal to acquire cannot be obtained, and for natural selection, the traits that let that animal survive through difficult situations can't be passed on and that animal will die out.

In what type of situation does a phenotypic distribution look like a bell shaped curve?

In normal distribution- a trait that isn't undergoing natural selection, intermediate phenotype is most common

Animals began to move onto _________________.

Land

Single-celled organisms changed early Earth's surface by depositing

Minerals

Eukaryotes are _______ and membrane-bound organelles.

Nucleus

Life moved onto land during the ________ Era.

Paleozoic

What periods were in the Paleozoic Era?

Permian, Carboniferous, Devonian, Silurian, Ordovician, Cambrian

What needs to happen in order for 2 populations to be isolated?

Populations are isolated when there is no gene flow between neighboring populations

Describe the theory of punctuated equilibrium:

Punctuated equilibrium is the theory that speciation occurs suddenly and rapidly, followed by long periods of little evolutionary change

An RNA molecule that can catalyze specific chemical reactions

Ribozymes

RNA world hypothesis is the theory that ______, not DNA, stored information in living things on early Earth.

Ribozymes

Why do real populations rarely reach Hardy-Weinberg equilibrium?

The factors of evolution are usually, or at least 1 is, acting on a population, which won't allow equilibrium - therefore, equilibrium is rare and most populations evolve

What can be concluded if real population data do not match those predicted by the Hardy Weinberg equation?

Then the population isn't in Hardy Weinberg Equilibrium - it's evolving

What is the main purpose of both relative dating and radiometric dating?

To determine how old a fossil is.

What periods were in the Mesozoic Era?

Triassic, Jurassic, Cretaceous

Humans have existed for

Very little

What is reproductive isolation?

When populations become so genetically different that they can't mate with each other

Eukaryotes are _______ which means they need oxygen to survive.

aerobic

Atmosphere made of:

ammonia, water vapor, methane, carbon dioxide

Heat is released by

asteroids, meteorites, and comets, and the radioactive decay of elements deep within Earth

Lasts several million years

epoch

Measure of the release of radiation

half-life

Most elements have several of these.

isotope

Cloud of gas and dust in space

nebula

Associated with rock systems

period

The oldest fossils are of bacteria that can carry out

photosynthesis

Iron sulfide _______hypothesis is simulated is the lab, making a ________ structure with compartments that could have acted as the first cell membranes.

• Bubbles • Chimney

During the _____________________, a huge diversity of ______________ species evolved.

• Cambrian Explosion • animal

________ membrane hypothesis is the discovery that lipid molecules spontaneously form membrane-enclosed ________.

• RNA • nebula

What is the theory of endosymbiosis?

• Simple prokaryotic cells were engulfed by larger prokaryotic cells around 1.5 billion years ago. • some of the smaller prokaryotes have survived • Over generations, the smaller prokaryotes may have gradually evolved into the organelles that today are mitochondria.

Organism trapped in tree resin that hardens after being buried.

Amber-preserved fossils

Give an example of a vestigial structure and explain how vestigial structures are significant to evolution.

An example of vestigial structures are the pelvic bones of a whale. Whales no longer use their pelvic bones, which probably is why they are so small in comparison to the rest of their bones. Vestigial structures are significant to evolution because they help show us how different animals are connected and furthermore, how they adapted and evolved into the different species that they are today.

Embryology provides evidence of evolution by revealing developmental homologies among species. Analyze and evaluate one example of such embryological evidence.

As species develop, they may form similar embryos which suggest a common ancestor. For example, birds, mammals, and fish develop gill slits and tails in their embryo, but only the fish keep the gills and tails as they mature.

Explain how the sequential nature of fossil groups found in rock strata supports Darwin's principle of "descent with modification".

As the environment changes, layers of fossils form and show that animals have evolved over the years and prove Darwin's theory of descent with modification.

Contrast background extinctions and mass extinctions:

Background extinctions happen constantly at a low rate, similar to speciation, whereas mass extinctions happen suddenly, rarely, and are very intense.

How is genetic variation measured in a population?

By mutations and recombination that create new offspring with different DNA

Relate catastrophism and gradualism?

Catastrophism and gradualism are both theories for evolution. Catastrophism is the belief that natural disasters shaped the Earth today, whereas gradualism is the belief that small, constant changes shaped our Earth.

What era means "ancient life"?

Cenozoic

Briefly explain how the geologist Charles Lyell influenced Darwin's ideas about how evolution works.

Charles Lyell influenced Darwin's idea about evolution because Lyell's idea that Earth changes from small, constant changes can translate to Darwin's idea that animals adapt and evolve from small, constant changes in the environment.

Occurs when unrelated species begin to resemble one another due to similar environmental pressures

Convergent evolution

Type of selection that favors 1 extreme phenotype

Directional selection

Type of selection that favors 2 extreme phenotypes

Disruptive selection

Occurs when closely related species become more and more different

Divergent evolution

Two related species can become more different over time. What type of evolution is this an example of?

Divergent evolution

Examples include the Paleozoic, Mesozoic, and Cenozoic

Era

Lasts tens to hundreds of millions of years

Era

How can sexual selection lead to highly exaggerated traits among males?

Females are very selective about who they mate with which drives the males to compete and evolve better, very exaggerated traits. This continues over generations (best traits selected) which only improves the traits

Caused by emigration or immigration, where genetic traits are gained or lost by populations

Gene flow

How can gene flow result in allele frequencies?

Gene flow is the immigration of animals and the movement of their alleles which result in a bigger, shared gene pool

All the genes present in a population of organisms

Gene pool

What can be predicted by the Hardy Weinberg equation?

Genotype frequencies in a population

Occurs when physical barriers exist that keep a population from breeding with species members on the other side

Geographic isolation

The term homologous comes from the Greek word homos, which means "the same". Explain how this meaning relates to homologous structures.

Homologous structures relate to the word homos because they are the same structures but are used in different animals and for different functions.

Fossils of organisms that existed only during specific spans of time are called

Index

Why is natural selection not considered a random event?

It is caused by environmental pressures, and the build up of allele frequencies (NOT random).

What does the Hardy Weinberg model show?

It shows that if there aren't any forces of evolution acting on a population, their allele frequencies will stay the same (constant).

Jean-Baptiste Lamarck hypothesized that changes in an environment led to an organism's greater or lesser use of a body part. Although his hypothesis was incomplete, what ideas related to evolution did Lamarck and Charles Darwin share?

Lamarck and Darwin both believed in inherited traits, but Lamarck believed that acquired traits could be inherited by offspring, which is incorrect.

Describe one idea about evolution that was proposed before Darwin published his theory of natural selection.

Lamarck had an idea about evolution before Darwin. His idea was that acquired traits are passed down to offspring, but that was incorrect because acquired traits (like being really muscular) can't be passed down to your children.

What era means "middle life"?

Mesozoic

Fossils that occur when _________________ carried by water are deposited around a hard structure, sometimes replacing the hard structure itself over time.

Minerals

Describe how mutation and recombination provide genetic variation to populations.

Mutations are DNA changes that make a new allele, and recombination are new allele combinations that may form in offspring; both result in variation (through different genetics)

Why must a population have genetic variation in order for natural selection to occur?

Natural selection can only occur if there is a difference within the species that results in those better suited to the environment (which will live on) and those who aren't and will die off, which is the process of natural selection. If they're all the same, none can be separated for natural selection.

What are three trends that biologists have identified in the transitional characteristics of different groups in the whale fossil record?

One trend that biologists have noticed in whale fossils is that the Pakicetus had a whale shaped skull with teeth for hunting, although it couldn't dive deep or hear well underwater. The Ambulocetus natans was an amphibian who ate fish and was about the size of a sea lion. Finally, the Dorudon was most similar to today's whales because it adapted shorter legs and a shorter neck with a longer tail. These trends prove that whales evolved from animals that walked on land millions of years ago.

Absent in atmosphere:

Oxygen

Relate fossils and paleontology?

Paleontology is the study of fossils. Fossils are very important to understand the past, and paleontologists discover and analyze fossils to do that.

Paleontology is the study of fossils or extinct organisms. Explain how this field is important to evolutionary biology.

Paleontology is very important to evolutionary biology because studying fossils help us understand the past and how animals are connected. It shows us how they adapted and explains why we have the species that we have today, and why they are how they are.

What era means "recent life"?

Paleozoic

Examples include the Cambrian, Jurassic, and Quaternary

Period

The largest units of geologic time are known as

Periods

What periods were in the Cenozoic Era?

Quaternary Tertiary

Measures the actual age of a fossil

Radiometric dating

Index fossils are a tool used in

Relative dating

What's the main difference between relative dating and radiometric dating?

Relative dating compares a fossil with the fossils of other plants and animals that are known to have lived in certain time periods.

Why are smaller populations more affected by genetic drift?

Smaller populations have less alleles which may not be able to "balance out" random changes, therefore genetic drift affects them more

Energy provided by:

Solar radiation and lightning

How are genes and proteins similar to homologous structures when determining evolutionary relationships among species?

Species that share genes and proteins are probably related, just like how species that share homologous structures are probably related, as well.

Type of selection that favors the intermediate phenotype

Stabilizing selection

What makes up a population's gene pool?

The combined alleles of all the individuals of a population

Explain what the following quote by Theodosius Dobzhansky means: "Nothing in biology makes sense except in the light of evolution."

The quote means that everything in biology relates to evolution and has come from it. The principles of evolution is what biology and other fields are based on.

Natural selection is based on four main principles: variation, overproduction, adaptation, and descent with modification. Briefly explain how each of these principles is necessary for natural selection to occur.

Variation is necessary for natural selection to occur because variation within a population leads to advantages and disadvantages, which leads to the success of one over the other. Overproduction can be advantageous because there is a better chance of that species surviving, but it is also disadvantageous because there are more animals competing for the same resources. Adaptation creates advantageous traits that can allow a species to survive better than other species. Finally, descent with modification is important for natural selection because over time, more species every generation will inherit the beneficial traits that make them more successful in survival and reproduction.

The term vestigial comes from the Latin word vestigium, which means "track or footprint". Explain how this meaning relates to vestigial structures.

Vestigial structures relate to the word vestigial because like a track or footprint, they reveal a trace of an ancestor within them. For example, whales have pelvic bones which are unused and therefore vestigial, but the presence of the pelvic bone suggests a time in the past where whales were in a position (possibly on land) to use that bone, revealing part of their history-a "trace".

What types of scientific evidence provide support for common ancestry among groups such as land mammals and whales? How would you assess the relative strength of these different types of evidence?

Whales have pelvic bones (which are vestigial) that suggest that they have an ancestor that used to walk on land before adapting to the water. This evidence is strong because it is objective-fossils are facts and part of science.

What is normal distribution?

When the frequency is highest near the mean and decreases toward each extreme (bell shaped curve)

An impression is left in sediment, and minerals fill the impression in, recreating the original shape of the organism.

natural cast

Lasts tens of millions of years

period

Most commonly used units of geologic time

period

Organism becomes encased in materials such as ice or volcanic ash, or immersed in a bog.

preserved remains

Infers order in which groups of organisms existed

relative dating

What's the process of permineralization?

• An organism dies • Sediments quickly cover its body • Pressure from additional sediment compresses the body. • Minerals slowly replace all hard structures, such as bone. • The fossils may be exposed millions of years after formation.

Name and describe 3 ways in which populations can become isolated:

• Behavioral - difference in mating behaviors prevent mating • Geographic - physical barriers (like mountains) that separate populations and prevent mating • Temporal - difference in reproductive time (AM vs PM, seasonal difference; times don't match up so they can't reproduce together)

Name and describe 3 ways in which natural selection can change the distribution of a trait.

• Directional selection- favors phenotype at one extreme, bell curve shifts, average changes • Stabilizing selection- favors intermediate phenotypes, peak of curve gets taller and more narrow • Disruptive selection- favors phenotypes at both extremes, center of curve dips

Miller-_______ experiment demonstrated _________ compounds could be made by passing electrical current (to simulate lightning) through s closed system that held a mixture of gases (to simulate the early atmosphere)

• Urey • Organic

What conditions are required for a population to stay in Hardy Weinberg equilibrium?

• very large population (no genetic drift) • no emigration/immigration • no mutations • random mating (no sexual selection) • no natural selection (equal alleles)