Evolution
Radiometric dating
is a technique that allows geologists to estimate the precise ages at which one geological formation ends and another begins.
The only chance for paleontologist to study a fossil occurs during the narrow window of time between...
its exposure and its destruction.
In south African rocks dating to 2.6 billion years ago, scientists have found remains of _____________ _________ that grew on land. Fungi, plants and animals did not arrive on land until much later.
microbial mats
Prokaryotes are-
microorganisms lacking a cell nucleus or any other membrane-bound organelles. Prokaryotes comprise two evolutionary distinct groups, the bacteria and the archaea.
The earliest land plants resemble ________ and ___________.
mosses and liverworts. they were likely low, ground-hugging carpets of vegetation.
The fossil record will never be complete because...
most organisms don't fossilize.
In the early 1900's, physicists discovered that atoms were either in a ___________________ or ____________ state. In both cases, the atom's state depended on its combination of subatomic particles.
permanently stable or unstable state.
The most persuasive evidence that the Earth is ancient came not from geologists but...
physicists. They discovered the structure of atoms, and their findings let to a reliable, precise way to estimate the ages of rocks.
Unstable isotopes have a fixed...
probability of decay.
Carbon from organisms is a lighter isotope than carbon from volcanos. So ....
rocks formed after the origin of life should record this shift.
The genetic variation among ___________ also far exceeds that of animals or plants.
single-celled life.
The less familiar known animal is the _______
sponges!
Some fungi help plants by...
supplying nutrients to their roots in exchange for organic carbon that the plants create in photosynthesis.
Synapsids are a lineage of...
tetrapods that emerged 300 million years ago and have rise to mammals. Synapsids can be distinguished from other tetrapods by the presence of a pair of openings in the skill behind the eyes, known as the temporal fenestrae.
Some hominins may have acquired a C4 signature in their teeth by eating...
the meat of grazing mammals.
nineteenth century scientist debated the age of the Earth. Early estimates were based on flawed assumptions about ...
the structure of the planet's interior.
Tetrapods are...
vertebrates with four limbs (or, like snakes, descended from vertebrates with four limbs). Living tetrapods include mammals, birds, reptiles, and amphibians.
Trilobites-
were marine arthropods that diversified during the Cambrian period and gradually died out during the Devonian period.
Green algae first appear _____ million years ago.
750
The oldest known track ways left by a vertebrate date back ______ million years. while the oldest known fossils of vertebrates with legs-known as ____________-are about _______ million years old.
-390 million -Tetrapods -370 million
Grasses, which use ____photosynthesis, are more efficient at extracting carbon dioxide from the atmosphere than ____ plants.
-C4 -C3
After Trilobites emerged during the ____________ period, for example, they flourished until 251 million years ago. The last trilobite species disappeared at around the same time that about 90% of all other species vanished.
-Cambrian
One of the most important Lagerstatten in the history of paleontology was discovered by ____________ in ____________
-Charles Doolittle Walcott in 1909 high in the mountain slopes of British Columbia. Quarries of this burgess Shale have now yielded more than 65,000 specimens representing 93 species.
We belong to the ___________, for example, a group that first appears in fossil-rich rocks in China called the ________________ ______________, which dates back 515 million years.
-Chordates -Chenjiang Formation
Many lineages of plants became extinct, but some such as _______ and _________ trees-have survived until today.
-FERNS -GINGKO TREES
The evolution of ___________ and other plant compounds allowed some lineages to grow stems, stalks, and trunks. Starting in the ______________ period, a number of large-sized plants lineages began to appear.
-Lignin -Carboniferous Period
Although early Ediacaran fossils were highly diverse and had unique body plans, only a fraction of them share traits with living species. nearly all Ediacaran species disappear from the Fossil record within ______million years of their appearance.
40
The oldest fungus fossils date back ....
400 million years.
Three domains that living things can be divided into:
1. Bacteria 2. Archea 3. Eukarya
The oldest known fossils of red algae date back ______ billion years.
1.2
For more than _____ billion years, only single-celled organisms inhabited the planet.
1.5
The oldest recognizable multicellular eukaryotes-filaments of some type of algae- are ______ billion years old.
1.6
Eukarya emerge in the fossil record only about ______ billion years ago. Their first fossils were _____________ organisms measuring about 100 micrometers across.
1.8
Biomarkers and the australian fossils of possible sponges suggest that animals had already evolved at least _____ million years before the start of the Cambrian period.
100
Dinosaurs emerged ______ million years ago
150
The Omo fossils are considered the oldest known fossils of members of our own species, at the age of...
195,000 years old.
The oldest fossils that clearly belong to our own species, were found in Ethiopia and are estimated to be nearly ______________ years old.
200,000
The Chauvet Cave is one of the oldest examples ofpainting in the world, dating...
32,000 years old
Grasses and certain other plants have evolved a different way to photosynthesize, incorporating carbon dioxide into _______-carbon molecules. This Process, called ____ photosynthesis, helps them to grow rapidly.
4, C4
Define prokaryote a. A descriptive grouping for microorganisms that lack membrane-bound organelles. b. A grouping useful in the classification of early microorganisms. c. A grouping often used instead of Archaea. d. a single-celled eukaryote e. A grouping designed to describe early fossils of plants
A
How can scientists determine that multicellular life arose more than once? a. Animals are more closely related to single-celled eukaryotes than to fungi. b. Fungi can produce multicellular structures. c. Bacteria live as multicellular groups called biofilms d. Scientists have no idea if multicellular life arose more than once.
A
Which isotope could be useful for sating a fossil found in relateively recent sediments? a. An isotope with amoderately high probability of deay. b. An isotope with a low probability of decay. c. Rubidium d. Strontium e. Any unstable isotope would be useful.
A
What sign would reflect a diet rich in C3 plants.
A relatively low ratio of carbon-13 to carbon-12
How did the fossils of the Burgess Shale form? a. The animals fell to the bottom of a deep lake and over thousands of years turned to rock. b. The animals dropped into anoxic ocean depths and were covered by fine sediment. c. The animals were rapidly covered by ash falling from a volcano d. Both A and B
B
Which group is not considered one of the major lineages of all living organisms? a. Bacteria b.Microbes c. Archaea d. Eukarya
B
starting around 50 million years ago the ancestors of whales evolved from land mammals into the ocean's top predators. At about the same time ______ evolved as the only flying mammals.
BATS
Although bacteria are considered single celled, they can communicate to each other through ____________.
BIOFILMS that regulate their growth and activity.
Carbon with: 6 neutrons: 7 neutrons: 8 neutrons:
Carbon-12 Carbon-13 Carbon-14
What evidence did Darwin use to predict the age of the Earth? a. Darwin didn't predict the age of the Earth b. Darwin couldn't predict the age of the Earth, because he didn't understand radioactive decay c. Darwin used processes he could observe, such as erosion and sedimentation's, to predict that the Earth must be hundred of millions years old. d. It doesn't matter, because Lord Kelvin refuted Darwin's evidence.
C
Which outcome would you predict if you could compare the isotopes of fossils of two species of human ancestors and found high ratios of carbon-13/carbon-12 in one and low ratios in the other? a. The species with high ratios likely lived in grasslands. b. The species with high ratios likely preferred eating shrubby vegetation. c. The species with high ratios likely ate a mixed diet. d. It would depend on what kind of human fossils. e. all of the above. f. None of the above.
C
Why is a notochord an important adaptation for understanding the evolution of humans? a. The development of a notochord occurred in early fish. b. A notochord is a backbone c. A notochord is characteristic of chordates d. A notochord serves to distinguish the Ediacaran fauna from the trilobites. e. The notochord is not an important adaptation for the evolution of humans.
C
Most plant species carry out ____ photosynthesis, so named because it incorporates carbon dioxide into a molecule with ____ carbone atoms.
C3, 3
Chemist have found that C_ plants have higher levels of carbon-13 than C_ plants do.
C4, C3
medical technologies can be used to study fossils as well, such as the _______ scan.
CT scan.
Nearly all living animal lineages, including chodates, evolved during the ______________ period.
Cambrian
What is an exception to the half-life rule?
Carbon-14 is continually generated in the earth's atmosphere due to cosmic rays that pass through and collide with the nitrogen atoms, converting them to carbon-14.
What allows us to know that synapsids were tetrapods? a. They lived on land. b. They were the dominant land animals c. They evolved into mammals. d. They had four legs that they used for walking. e. All of the above are true.
D
What is an isochron? a. The ratio of rubidium (Rb) to strontium (Sr) b. The half-life of an isotope c. The slope of the line describing the ratio of 87Sr to 86Sr. d. A line on a graph of isotope ratios that indicates mineral samples formed at a similar time.
D
A model organism used to study the steps leading to multicellularity is ______________ ____________________, a slime mold that lives most of its life as a single celled predator on bacteria. When its prey runs out, it joins with thousands of their D. discoides to form a slug-like "body" that crawls through the soil. Eventually building a "stalk" on top of which a ball of spores forms.
Dictyostelium discoides
Geologists can use carbon isotopes to get clues as to what some extinct animals were eating. This can be done because..
Different plants have slightly different ratios of carbon isotopes, depending on how they carry out photosynthesis.
Multicellularity likely developed independently in _________ and ________.
animals and fungi
Earth's natural supply of radioactive isotopes has been steadily __________ since it formed.
Dwindling
How did scientists determine that Tyrannosaures rex could not run very fast? a. They compared skeletal structure of T. rex to modern animals to determine the size of T. rex's muscles. b. They used living animals to test a model they had developed on the bio-mechanics of running. c. They used evolutionary theory to determine the most closely related living organisms to T. rex. d. They developed a biomechanical model of running animals to determine how much force leg muscles of a given size could generate. e. All of the above.
E
What independent lines of evidence have scientists used to determine the history of life on Earth? a. Zircons. b. Behavior of living species c. Fossilized dung d. Oxygen isotopes e. All of the above
E
Ediacaran fauna
Earliest generally accepted animal fossils, dating from about 575 million years ago looked like fronds, geometrical disks, and blobs covered with tire tracks.
Only one group of organisms alive today releases methane: a lineage of archaea called _____________
Eukaryarchaeota. Among the places these organisms live today are: -digestive tract of cows-cow burps have methane.
Today most lineages are dominated by what type of plants?
FLOWERING PLANTS during the Jurassic and Cretaceous periods, flowering plants became more abundant and diverse.
Which fossils are mingled with the fossils of plants. Showing that they helped each other move from water to land.
FUNGUS
Today, _______ are one of the most wide-spread forms of flowering plants. They cover the great expanses of savannas and prairies of the world.
GRASSES
____________,_____________,_____________,______________ all use photosynthesis to capture energy to grow.
Green plants, green algae, brown algae, and red algae.
Hominins include...
Humans as well as all species more closely related to humans than to chimpanzees. Within this group, humans are the only surviving members.
What are stromatolites?
Layered mats of bacteria. They are relateively rare today. Fossils of stromatolites in Australia date back over 3.4 billion years are among the earliest evidence of life on Earth.
By weight, __________ make up the worlds bulk in biomass.
Microbes
William Thomson (Lord Kelvin; 1824-1907).
Most prominent skeptics of the earth being ancient. He was a physicist that argued that the earth was less than 20 million year old. Based on measurement of Earth's rate of heat loss.
The number of _______ determines if an isotope is stable or unstable.
Neutrons Carbon-12 is stable because there is an equal number of protons and neutrons. Carbon-12 will remain as it is for a billion years.
A biomarker named ______________, is derived from pigments made by purple sulfur bacteria (Chroatiaceae).
Okenane
The earliest hints of terrestrial life come from _______________.
PROKARYOTES
The number of __________ in an atom determine which element it belongs to.
PROTONS
Coal is actually...
Plant material that was transformed under tremendous pressure and heat
Okenane presence is used to hypothesis that _______ _________ bacteria were present on Earth 1.64 billion years ago.
Purple Sulfur.
Before the rise teleost fishes, some of the ocean's top predators were giant sea ____________.
SCORPIONS
The oldest Hoinin fossils are more recent. They include _______________________, which was discovered in 2001 in Chad and dates back about 7 million years.
Sahelanthropus it was the oldest known bipedal hominid. Discovered on the edge of the Sahara desert in 2001.
Charles Darwin is now best known as an evolutionary biologist, but he first came to fame as a _____________.
geologist.
The only traces of the first few hundred million years of the crust's history are preserved in microscopic crystals known as...
ZIRCONS
Biomarkers
a measurable substance in an organism whose presence is indicative of some phenomenon such as disease, infection, or environmental exposure. molecular evidence of life in the fossil record. Can include fragments of DNA, molecules such as lipid, or specific isotopic ratios.
By measuring the concentrations of certain radioactive isotopes and stable ones in a sample. The steady decay rate of radioactive isotopes allows scientists to estimate how long the decay has been occurring in a rock- thus estimating _____________.
a rocks age
Chordates-
are members of a diverse phylum of animals that includes the vertebrates, lancelets, and tunicates. As embryos, chordates all have a notochord (a hollow nerve cord), pharyngeal gill slits, and a post-anal tail. Many present-day chordates lose or modify these structures as they develop into adults.
Lagerstatten Fossils
are sites with an abundant supply unusually well-preserved fossils-often including soft tissues- from the same period of time. In almost every instance, the fossilized animals were swept into anoxic pools, lagoons, or bays. This is due to the lifelessness of these environments where bacteria and other scavengers could not destroy the animals' bodies.
The earliest signs of life, such as the Stromatolites, strongly resemble living ___________.
bacteria
Teleosts are a lineage of...
bony fish that comprises most living species of aquatic vertebrates. Teleosts include goldfish, salmon, and tuna. They can be distinguished from other fishes by unique traits, such as the mobility of an upper jawbone called the premaxilla.
Due to heaviness, the ratio of ___________to carbon-12 is lower in plants than it is in the atmosphere.
carbon-13
Stromatolites form when biofilms of microorganisms, especially _______________ trap and bind sediments to form layered accretionary structures.
cyanobacteria
The rise in oxygen was likely due to ______________, which release oxygen during photosynthesis.
cyanobacteria
Only after the ______________ were gone did mammals start evolving into dramatically new forms.
dinosaurs
Notochords-
flexible, rod-shaped structures found in the embryos of all chordates. Notochords served as the first "backbones" in early chordates, and in extant vertebrates the embryonic notochord becomes part of the vertebral column.
It is usually not possible to directly date a ______ through radiometric.
fossil