Name: mass extinction and the fossil record
Uploaded: 2019-01-29T11:04:46.000Z
Duration: 5 min 25 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

Biological Evolution- Unity and Diversity

LS.Bio.10.1

Extinction

What do dinosaurs, Tasmanian Tigers and Hoopoe Starlings have in common? The answer is the subject of today&#39;s lab, extinction. Extinction occurs when a species cannot survive in its environment to reproduce and cannot move to a new one. Woolly mammoths, for example, were thought to have died as a result of climate change making its habitat and the rest of the planet too warm. Extinction has happened for as long as there has been life on earth. In fact, an estimated 99% of all species that ever existed have gone extinct. 
Most of these extinctions happened over time because of environmental changes like our woolly mammoth. But other factors such as competition for resources with other species and inability to avoid predation can also drive a species to extinction. Take these fish, for example. Both species share a habitat, but the green fish is better at evading predators making its survival more likely and eventually driving the orange fish extinct. Over hunting and other human made phenomena such as pollution can also cause the extinction of a species. 
Extinctions that occur on a global level are called mass extinctions and these are typically caused by major catastrophic events like impacts from space, significant volcanic activity and other phenomena that cause global climate change. During these events, high rates of extinction exceed the rates of new speciation resulting in a global loss of species. 
The best known mass extinction is the Cretaceous-Paleogene or K-Pg extinction, famous for ending the reign of the dinosaurs. This extinction can even be seen in the rock layers or strata of the earth where we see an abrupt loss of species from the fossil record around 66 million years ago, which also coincides with a unique sediment layer containing iridium a metal not often found in the earth&#39;s crust. Iridium is, however, present in high amounts in asteroids, giving scientists a clue to the cause of the extinction. The impact at the Yucatan Peninsula in Mexico created the 180 kilometer wide Chicxulub Crater and triggered a string of catastrophic events that would alter the earth forever. First, fire storms would have ravaged the North American continent creating a huge cloud of smoke and dust. Debris ejected from the collision would have become trapped in the upper atmosphere causing a blanketing effect, which trapped deadly amounts of infrared radiation in the atmosphere. Volcanic eruptions and widespread geological instability following the impact fueled the smothering of the earth yet further and as the soot, smoke and volcanic ash blocked the sun, many plants were no longer able to photosynthesize and so perished. Without food, the herbivores were the next to die out, followed closely by the predators. The volcanic emissions and resulting smog caused acid rain which acidified the oceans wiping out many aquatic species. Soon, the acidic atmosphere and dense fog blocking the sun&#39;s warmth led to a deep freeze with global temperatures dropping below zero for several years. The mass extinction caused by these drastic environmental changes affected every known and three quarters of all species alive at the time went extinct in the evolutionary equivalent of the blink of an eye. 
Over time, as the earth&#39;s climate slowly returned to normal, the remaining species which included small mammals rebounded and underwent adaptive radiation to fill the many newly vacated In this way, the loss of a great number of species during the mass extinction opened up room for the expansion and speciation of others. 
In this lab, you will examine diversity data for several distinct taxa at different time periods around the Cretaceous-Paleogene extinction.

extinction

<h4>The History of Life on Earth</h4>
Fossils of organisms that were different from anything alive today had been documented as early as the 17th century, but it was not until the early 19th century that scientists began to recognize that the successive layers of fossil bearing rocks were like successive pages in the history of life on earth. Although this recognition gave rise to the birth of the field of paleontology, the idea of complete global extinction of a species had yet to be fully accepted. At that time, it remained viable to argue that our knowledge of the world was limited, therefore scientists considered the possibility that organisms known only from fossils might still live on in some unexplored portion of earth.
When Charles Darwin published &#8220;On the Origin of Species&#8221; in 1859, the concept of the extinction of species was becoming more accepted, but the cause of extinctions remained a mystery. Continuous extinction was integral to Darwin&#8217;s theory of natural selection, as he viewed it as a logical result of the evolution of species that were more competitive, better predators, or more fit than their ancestors in another way. Therefore, the ancestors had gone extinct to be replaced by their superior descendants. The only illustration Darwin included in his book is of an early phylogenetic tree, which he referred to on multiple occasions to support his argument for extinction being a by-product of evolution.
Every living organism comes to existence, prevails for some period of time, and eventually perishes. The same is true for species as well, hence the ultimate fate of all species is extinction. A species goes extinct when it can no longer survive and reproduce in its environment and cannot move to a new one. It is estimated that over 99% of all species that have ever existed have gone extinct, with most having an average &#8220;lifespan&#8221; of 1-10 million years. Extinction can be gradual due to slow environmental changes or an inability to compete with an emergent species, or it can be sudden due to catastrophic events, habitat destruction, pollution, or overhunting.
<h4>Extinction on a Large Scale</h4>
Mass extinctions, or extinction events, are large worldwide decreases in biodiversity, when rates of extinction exceed rates of speciation. Mass extinctions are generally caused by geological or astronomical events, such as volcanic eruptions, changes in atmospheric composition, sea level rise or fall, global cooling and warming, and asteroid impacts.
Five major mass extinction events have been identified and have been used to subdivide geologic time into distinct eras or periods that are nested within eras. When multiple species go extinct very abruptly they disappear from the fossil record, providing a metric for the end of a given subdivision of the geologic time scale and the beginning of a new time period.
<h4>The Permian-Triassic Extinction</h4>
The largest mass extinction, the Permian-Triassic extinction, also known as &#8220;The Great Dying&#8221; or the &#8220;Permian-Triassic disaster&#8221; took place approximately 252 million years ago at the end of the Permian period, driving over 90% of all species to extinction1. Another well-known mass extinction is the Cretaceous-Palaeogene (K-Pg) or Cretaceous-Tertiary (KT) Extinction, which occurred approximately 66 million years ago2. While the cause of the K-Pg extinction has been widely debated, consensus has settled on an asteroid impact on the Yucatan Peninsula of Mexico as the most important cause of the event. This massive impact led to geologic instability in certain areas, leading to earthquakes, significant amounts of volcanic activity, as well as dramatic sea level rise. In addition, it also triggered massive fires, which in turn filled the air with a thick layer of ash, smoke, and dust, blocking out the sun and leading to a period of global cooling.
The timing of the asteroid impact follows the massive volcanic eruptions that caused the formation of the Deccan Traps, in west-central India. These eruptions happened over an interval of as long as 30,000 years and began before the asteroid impact. They caused the largest volcanic formation on earth that covers an area of over 200,000 square miles. These eruptions would have also caused sustained climate change and hence are seen as either an alternative cause to the asteroid impact or an augmentation of the environmental disruptions that followed the impact.
<h4>Global Loss of Species</h4>
K-Pg event is most famous for the extinction of dinosaurs; however, dinosaurs were not the only taxa affected &#8211; approximately 75% of all species went extinct during this event. Nevertheless, not all taxa were affected equally, and some later benefitted from the opening of previously occupied niches2. Mammals and amphibians were both part of the latter group. While diversity was lost during the extinction, these two taxa lost diversity at a lower rate than many other taxa and both groups underwent an adaptive radiation following the demise of other large tetrapods, such as the archosaurs. Of the Archosaurs, only the lineages that led to birds and crocodiles survived. Hence, non-avian dinosaurs are not observed past the K-Pg boundary in the fossil record, and they are believed to have died out quickly and completely due to their lack of ability to take shelter and their reliance on carnivorous diets. The fossil record for insects shows wide swings at the start of the Paleogene. It is possible this variation is due to the imperfection of the fossil record and some stages were more prone to preserving fossils than others. It is also known, however, that insects experienced similar trends to other taxa, decreasing immediately following the K-Pg extinction and then rebounding. A high point at the Thermal Maximum can also be observed for this taxon. Osteichthyes, or the bony fish, also experience an irregular pattern of diversity. Deep water marine fossils in particular are difficult to find, which could contribute to this irregularity, however it is worth noting that the highest diversity of bony fish is at the Thermal Maximum. Shallow seas are thought to have experienced the worst effects during the extinction event due to the larger impact of sea level rise and reduced photosynthesis compared to other marine habitats. Molluscs experienced a huge decline following the K-Pg extinction and these numbers are not regained by the end of the Paleogene. Echinodermata and Crustacea experience similar levels of decline, however these numbers may also be affected by the lack of fossilizing structures in both of these groups.
Some scientists have suggested that we entered a new geologic era known as Anthropocene, along with the &#8220;Sixth Mass Extinction&#8221;1-2. This suggestion is based on the global changes as well as the high rate of global extinction as a result of human activity including overhunting, pollution, habitat destruction, invasive species, and climate change. Because the current extinction is caused by human activity, it is unlike the other mass extinctions, which have largely resulted from astronomical and geological processes. The current rate of extinction is up to 100 times higher than it is expected to have been without human influence and it is likely higher, considering species that have not yet been discovered. Considering the rate of Anthropocene extinction is equal to or greater than those associated with the earlier mass extinction events, rapid action is required to reverse the huge losses to vulnerable populations.
<h4>References</h4>
<ol class="references">
	<li>Benton, Sarda Sahney and Michael J. Recovery from the most profound mass extinction of all time. Proc Biol Sci. 2008, Vol. 275 , (1636) 759&#8211;765.</li>
	<li>Thomas John Dixon Halliday, Paul Upchurch, and Anjali Goswami. Eutherians experienced elevated evolutionary rates in the immediate aftermath of the Cretaceous&#8211;Palaeogene mass extinction. Proc Biol Sci. 2016, Vol. 283, (1833) 20153026.</li>
	<li>Barnosky AD, Matzke N, Tomiya S, Wogan GO, Swartz B, Quental TB, Marshall C, McGuire JL, Lindsey EL, Maguire KC, Mersey B, Ferrer EA. Has the Earth&#39;s sixth mass extinction already arrived? Nature. 2011, Vol. 471, (7336) 51-7.</li>
	<li>Madliger CL, Franklin CE, Hultine KR, van Kleunen M, Lennox RJ, Love OP, Rummer JL, Cooke SJ. Conservation physiology and the quest for a &#39;good&#39; Anthropocene. Conserv Physiol. 2017, Vol. 5, (1) cox003.</li>
</ol>

The History of Life on Earth
Fossils of organisms that were different from anything alive today had been documented as early as the 17th century, but it ...

Education

JoVE Lab Manual

Ecology

mass extinction and the fossil record

Mass extinction is a major loss of species, and the fossil record shows how these events changed life on Earth. Fossils from different rock layers helped scientists see that life has a long history. In the early 19th century, that idea helped launch paleontology, the study of fossils and ancient life.

At first, many scientists did not fully accept that a species could disappear forever. They thought unknown organisms seen only in fossils might still live in unexplored places on Earth. By 1859, when Charles Darwin published On the Origin of Species, extinction was becoming more accepted, but its cause was still unclear. Darwin linked extinction to natural selection, where better-adapted species outcompete older ones and replace them over time.

A species goes extinct when it can no longer survive and reproduce in its environment and cannot move to a new one. Over 99% of species that have ever existed are estimated to have gone extinct. Most species last about 1 to 10 million years. Extinction can happen slowly because of environmental change or competition, or suddenly because of disasters, habitat loss, pollution, or overhunting.

Mass extinctions, also called extinction events, are global drops in biodiversity. They happen when extinction rates become higher than speciation rates, which is the rate at which new species form. These events are often linked to volcanic eruptions, changes in air composition, sea level changes, global cooling or warming, and asteroid impacts. Five major mass extinctions are recognized, and they help divide geologic time into eras and periods. When many species disappear at once, they also leave a clear signal in the fossil record.

The largest known mass extinction was the Permian-Triassic extinction, also called the Great Dying, about 252 million years ago. It happened at the end of the Permian Period and eliminated over 90% of species. Another famous event was the Cretaceous-Palaeogene, or K-Pg, extinction about 66 million years ago. Scientists now agree that a huge asteroid impact on the Yucatan Peninsula of Mexico was a major cause. The impact likely triggered earthquakes, major volcanic activity, and sea level rise, and it also caused fires that filled the air with ash, smoke, and dust. That blocked sunlight and led to global cooling.

The K-Pg event also came after the Deccan Traps eruptions in west-central India. These eruptions lasted as long as 30,000 years and formed the largest volcanic feature on Earth, covering more than 200,000 square miles. They likely added to long-term climate change. For that reason, some scientists view the eruptions as an alternative cause or as an added stress that worked with the asteroid impact.

The K-Pg extinction is best known for the loss of dinosaurs, but they were not the only group affected. About 75% of all species went extinct. Some groups later benefited when empty ecological niches opened up. Mammals and amphibians lost diversity at a lower rate than many other groups and then diversified after large tetrapods such as archosaurs declined. Among the archosaurs, only the lineages leading to birds and crocodiles survived. Non-avian dinosaurs do not appear above the K-Pg boundary in the fossil record, and they are thought to have died out quickly because they could not shelter well and depended on carnivorous diets.

Other groups also show the effect of the K-Pg event in different ways. Insects dropped after the extinction and then rebounded, although changes in fossil preservation may affect the pattern. Bony fish, or Osteichthyes, show an uneven diversity record, especially because deep-water fossils are hard to find. Shallow seas may have been hit hardest because sea level rise and reduced photosynthesis affected them more. Molluscs declined greatly and did not recover by the end of the Paleogene. Echinoderms and crustaceans also declined, although their fossil record may be affected by the lack of hard parts that fossilize easily.

Some scientists think Earth may now be entering the Anthropocene, along with a possible Sixth Mass Extinction. This idea is based on rapid global change and high extinction rates caused by human activity. Overhunting, pollution, habitat destruction, invasive species, and climate change all contribute. The current extinction rate may be up to 100 times higher than expected without human influence, and it could be even higher because many species have not yet been discovered. Because this rate is comparable to earlier mass extinctions, rapid action is needed to protect vulnerable populations.

Mass Extinction and the Fossil Record

animal behavior

Drosophila Taxis in Animal Behavior

Drosophila taxis behavior is a key part of animal behavior studies. The common fruit fly, Drosophila melanogaster, is a widely used model organism in biology. It is easy to keep in small tubes, it has a short generation time of about two weeks, and males and females are easy to tell apart because males have black coloration toward the posterior and females have banded abdomens. Scientists have used Drosophila for more than a century. Thomas Hunt Morgan and his students studied mutant flies in...

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measuring biodiversity

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Mass extinction is a major loss of species, and the fossil record shows how these events changed life on Earth. Fossils from different rock layers helped scientists see that life has a long history. In the early 19th century, that idea helped launch paleontology, the study of fossils and ancient life. At first, many scientists did not fully accept that a species could disappear forever. They thought unknown organisms seen only in fossils might still live in unexplored places on Earth. By 1859,...

species distribution and biogeography

Island Biogeography and Species Richness

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population growth

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Population ecology examines how a species population changes over time. A population is a group of individuals of the same species living in the same area at the same time. To persist, a population must grow or at least stay about the same size. Ecologists study birth rate, death rate, and age distribution to understand whether a population is increasing, declining, or at risk of extinction. Population ecologists use models to predict how population size changes. Two simple models are...

community diversity

Measuring Ecosystem Health

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climate change

Climate Change Effects on Sea Level and Species

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group behavior

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optimal foraging

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sexual selection and mate choice

Mate Competition and Fitness Traits

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eusociality and division of labor

Honeybee Altruism and Inclusive Fitness

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ecology

Learn how mass extinctions appear in the fossil record, from the Great Dying and K-Pg event to today’s human-driven extinction crisis.

Mass Extinction and the Fossil Record | JoVE K12

Earth and Environmental Science

Earth and Human Activity

ESS.EES.5.1

ESS.EES.6.1

Pennsylvania State Academic Standards

Earth and Space Science

Earth's Systems

3.3.9-12.N

History of Earth

3.3.9-12.F

3.3.9-12.J

Weather and Climate

3.3.9-12.E

Life Science

Natural Selection and Evolution

3.1.9-12.X

Louisiana Student Standards for Science

High School

Earth Science

Earth’s Systems

HS-ESS2-4

HS-ESS2-6

HS-ESS2-7

Human Sustainability

HS-ESS3-1

Life Sciences

Biological Evolution: Unity And Diversity

HS-LS4-5

Environmental Science

ecosystems-interactions-energy-and-dynamics

Ecosystems: Interactions, Energy And Dynamics

HS-LS2-7

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Diversity And Interdependence Of Life

Biodiversity

Virginia  Standards of Learning

HIgh School

ES.9

ES.9.a

ES.9.b

ES.9.c

ES.9.d

LS.11

LS.11.a

Minnesota Academic Standards in Science

4.1.1 9L.3.2.1.5

Texas Essential Knowledge and Skills

Earth Systems Science

112.49.c.8.

112.49.c.8.H.

Alabama Course of Study Science

9-12.ESS.2.5.b

Next Generation Science Standards

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

HS-LS3-3

HS-LS4-3

Florida Department of Education

SC.912.L.15

SC.912.L.15.3

BIO.9

BIO.9.B

Georgia Standards of Excellence

Geology

Geologic Time

SG3.b

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

Biological Evolution: Unity and Diversity

B-LS4-5.

new-york-state-science-learning-standards

New York State Science Learning Standards

Inheritance and Variation of Traits

HS-LS3-3.

HS-LS4-3.

HS-LS4-5.

Explore diversity and extinction during the Paleogene Epoch with a student reading supplement and a spreadsheet-based class activity using Excel or similar software.

Paleogene Biodiversity After the Mass Extinction | JoVE K12

Use fossil diversity data to predict and graph taxon changes across the K-Pg boundary, compare results, and test the Paleocene-Eocene Thermal Maximum.

Diversity Shifts After the K-Pg Boundary | JoVE K12

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Formation of Species

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Speciation Rates

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Genetics of Speciation

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Hybrid Zones

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What is Natural Selection?

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Types of Selection

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Frequency-dependent Selection

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Limits to Natural Selection

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Natural Selection

Fitness
Widespread variation of phenotypes in natural populations provides the raw material for evolution, which is the change in the inherited traits of ...

Simulating Natural Selection
ExpandTo prepare for the lab, set out workstations for each student pair containing 6 white, 6 black, and 13 gray 12 inch ...

Simulating Natural Selection
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Artificial Selection

Natural Selection and Adaptive Evolution
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Observing Artificial Selection in Plants
ExpandTwo weeks before beginning the pollination experiments, collect a sufficient amount of small pots with a ...

Observing Artificial Selection in Plants 
ExpandTo begin the experiment, collect five two-week old grown plants from the generation one population that ...

Analyze and interpret data to summarize how various factors such as geographic isolation, pesticide resistance, antibiotic resistance can influence natural selection.

LS.Bio.9.1

Phylogenetic Trees

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Conditions on Early Earth

Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen ...

The Colonization of Land

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What is Evolutionary History?

Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and ...

The Evidence for Evolution

Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of ...

The Fossil Record

The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms ...

Convergent Evolution

Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure ...

Gene Evolution - Fast or Slow?

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Genome Size and the Evolution of New Genes

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Gene Families

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types-of-genetic-transfer-between-organisms

Types of Genetic Transfer Between Organisms

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Ribozymes

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Construct an explanation to illustrate how common ancestry and biological evolution are supported by multiple lines of empirical evidence.

LS.Bio.9.2

Use models to illustrate the conditions required for natural selection, including the overproduction of offspring, inherited variation, and the struggle to survive.

LS.Bio.9.3

Construct an explanation to explain how natural selection leads to adaptations within populations.

LS.Bio.9.4

Diversity and Extinction during the Paleogene Epoch
ExpandFirst, familiarize yourself with the extinction reading supplement for the background on what ...

Diversity and Extinction during the Paleogene Epoch
ExpandBegin this procedure by reading the extinction reading supplement that has been printed out for ...

Construct explanations to illustrate how varying environmental conditions may result in: changes in the number of individuals of a species, the emergence of new species over time, or the extinction of other species.

Understand natural selection as a mechanism for biological evolution.

Mass Extinction and the Fossil Record

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