Ecology and the Environment: L14
What percentage of the described species are vertebrates?
1%
What are the two ways that biodiversity are estimated?
1. Extrapolation from fractions 2. Extrapolation from taxonomic-scaling.
Name a few examples of ecosystem functions and services.
1. Primary production - the process by which trees and other plants use sunlight to covert inorganic matter into new organic tissue. (function) 2. The production of wood provides benefits to humans (service)
How many species are discovered every year?
15,000 species are identified each year.
Around which latitude is species richness greatest for trees?
An almost linear curve and is the highest at the lowest altitudes (25-45 degrees) (line starts high and gets lower from left to right)
What is an ecosystem function?
An ecological process that control the fluxes of energy, nutrients and organic matter through an environment.
Around which latitude is species richness greatest for birds?
Around 30-50 degrees N. (Bell shaped curve kind of)
Around which latitude is species richness the greatest for mammals?
Around 35-45 degrees N. (Bell shaped curve kind of)
Describe the utilitarian value between amphibians and drug discovery.
As an example of the utilitarian value of amphibians, your reading discussed several drugs that were first isolated from frogs. Epibatidine is an alkaloid that originally is found in the skin of a neotropical poisonous frog, Epipedobates tricolor, found in modern Ecuador. It was initially isolated by John Daly at the National Institutes of Health, and was found to be a powerful analgesic, about 200 times more potent than morphine. The Australian green tree frog and other species secrete skin peptides. One of them, called caerin, inhibits the HIV virus.
Describe some utilitarian values of biodiversity relating to agriculture.
Biodiversity has been critical to agriculture and food supplies. All domestic crops and livestock were originally wild organisms. Biotechnology allows us to inject genes directly into domesticated plants and animals. The genes we insert to produce, say, frost-resistant strawberries, have to come from somewhere. You can't just go to a molecular biology facility and ask them to invent a gene that will make strawberry plants hardier. No one has the faintest idea what that gene would be, what its precise instructional coding would be, or where it might be inserted into the chromosomes of the strawberry cells. Biotechnology works the old-fashioned way: One must first find a genetic feature that performs the desired function, before it can be extracted, manipulated, and inserted with the marvels of modern biotechnological technique into the stock where you would like to see that desired effect expressed. That means we must find genetic variation in the usual place: in nature, in wild versions of domesticated species, and in their nearest relatives.
Why does biodiversity matter from an ecological perspective?
Biodiversity is critical to maintaining ecosystem services.
How would you study beetles more than 100 ft up in the canopy?
By using a fog machine loaded with insecticide. The fogging machine produces warm rising clouds of knock down insecticide. Insects fall to the ground and are collected on plastic sheets.
What is the canopy?
Communities of forest trees have vertical structure and competition for light is intense. The trees in the tropics can be as tall as a 15 story building. The vertical structure of the plant community provides a physical framework in which many forms of animal life are adapted to live. The upper layer or canopy is the primary site of energy fixation through photosynthesis. Many organisms, like the beetles that Erwin studies, are adapted to live in the canopy layer.
How is a dog an example of the variation of species?
Dogs were probably the first tame animals. They have accompanied humans for some 10,000 years. Some scientists assert that all dogs, domestic and wild, share a common ancestor in the small South Asian wolf. Today humans have bred hundreds of different domestic dog breeds—some of which could never survive in the wild. Despite their many shapes and sizes all domestic dogs, from Newfoundlands to pugs, are members of the same species—Canis familiaris. The variation within species is another reason that leads to the variation in the number of identified species.
How did Erwin use the fogging study to estimate biodiversity?
Erwin thought that if on average, each tree had 163 host specific beetles and that if there are 50,000 different species of trees in the tropics that there must be about 8 million species of canopy dwelling beetles. In Erwin's study he didn't really study the ground dwelling beetles so if you account for them the number of generalist beetles in the canopy would raise the total to somewhere around 12 million beetles. Beetles are known to make up about 40% of tropical arthropods which means that their might be as many of 30 million species of tropical arthropods.
Describe extinction from a historical perspective.
Extinction has always been a normal part of life on Earth however, it is typically balanced with speciation (the creation of new species). Four billion species have lived on Earth, of which 99% have gone extinct. The critical question is is extinction happening at a faster rate now than it has in the past?
Explain the historical extinction trends and compare it to that of today's trends.
For any one species, extinction may seem catastrophic.... but in the grand scheme of things, extinction is business as usual. Extinctions occur continually, generating a "turnover" of the species living on Earth. This normal process is called background extinction (green shaded area). This process is opposed by the development of new species (called speciation). Thus new species evolve and species go extinct continually. Sometimes, however, extinction rates rise suddenly for a relatively short time—an event known as a mass extinction (marked with red arrows). Short is a relative term here we are talking geologic time so these events occur over thousands or millions of years. Another important point is that past mass extinctions were caused by natural causes.
What is the ratio of species that go extinct vs. the species that are discovered annually?
For every species identified, two go extinct (30,000 extinct/ 15,000 discovered)
How did we estimate the number of species using ratios of known to unknown faunas?
For mammals, birds, and other large and well documented animals, there are roughly twice as many tropical as temperate species. If the same ratio is true for other organisms then with 1.5 million species described and 2/3rds of these being temperate zone, the global total would be around 3 million species total.
Explain how the number of known taxa has changed over time.
From Linnaeus to today, the number of phyla discovered asymptotes (flattens out) by the year 1900 indicating that by 1900 we had discovered most phyla on the planet (around 30). However the number of species known has increased every year since the time of Linnaeus which indicated that we still don't know all of them.
What are the different rainforest levels?
From bottom to top they are: 1. The Floor 2. Shrub layer (10 m) 3. Understory (20 m) 4. Canopy (40 m) 5. Overstory (50 m)
What are the current best estimates of the number of species?
From these two approaches scientists have proposed a range of 3-100 million species. There is some consensus among scientists that the number of species is probably in between the range at about 12.5 million.
What happened when Erwin fogged trees?
He fogged 19 trees that were all the same species and collected the everything that fell out.
What were the results of the fogging study?
He found organisms of different trophic groups: herbivores, scavengers, predators and fungivores. Each tree had 1143 different species on average. Some of the beetles that Erwin found were host specific (about 163). Meaning that that species of beetle is only found on one species of tree. Some were generalists meaning that you can find them on lots of different species of trees.
What is unique about the Monarch Butterflies of North America?
In all the world, no butterflies migrate like the Monarchs of North America. They travel much farther than all other tropical butterflies, up to three thousand miles. They are the only butterflies to make such a long, two way migration every year. Amazingly, they fly in masses to the same winter roosts, often to the exact same trees. Their migration is more the type we expect from birds or whales. However, unlike birds and whales, individuals only make the round-trip once. It is their children's grandchildren that return south the following fall.
What is the relationship between species richness and latitude?
In general, there are about twice as many species in the tropics than in the temperate zone. Note these figures depict North American Species Richness. (subtropics to the arctic) Note the trends and richness of trees and mammals and birds that are shown in the figures.
What is the Linnaean Classification Scheme?
In the 1700s, Carl Linnaeus developed a taxonomic classification scheme still used today (Kingdom, Phylum, Class, Order, Family, Genus, Species). The system is hierarchical such that there are only a few families, more, more phyla, more classes, more orders and so on.
What is a tropical rain forest?
It has distribution in equatorial and subequatorial regions. In tropical rainforest, where rain is relatively constant, while in tropical dry forests precipitation is highly seasonal. The temperature is high year round (25-29˚C) with little seasonal variation. (Found in all of the continents except Europe.
What is an ecosystem service?
It is a service that benefits that ecosystems provide to humanity.
How many species go extinct every year?
It is currently estimated that about 30,000 species go extinct annually.
What does it mean about the species we have left to discover if there are an estimation of 12.5 million total species?
It means we have only described a small fraction of the species that exist on the planet and there is a lot more out there to discover. One point made is that for 85% of the 1.5 million species that have been described, we only know what they look like and where they were collected from. We do not know how many there are or their range let alone anything about their basic biology or ecology. We understand very little about some of the organisms that impact us the most like bacteria and viruses.
What was in the 10th edition of Systema Naturae?
It was printed in 1758 and it classified 12,000 species of plants and animals.
If 15,00 species are discovered each year why do you think this one made the headlines? (A New Snub Nosed Monkey Discovered, Eaten.
Mammals are the most identified and we have discovered most of them due to people's interest and their relative size.
Describe some utilitarian values of biodiversity relating to pharmaceuticals.
Many new drugs are discovered in natural products. Worldwide, the pharmaceutical natural-product patents from 1984-2003 have been increasing each year. The data are for all worldwide grants for patents claiming natural products as pharmaceuticals. A single natural product can give rise to several patents based on filings in multiple countries, or for multiple indications. In 2003, over 300 patents were issued for pharmaceuticals derived from natural products.
Why does biodiversity matter?
Moral, ethical and aesthetic values, utilitarian values, ecosystem values.
Where have most natural history museums have been located?
Most museums and their curators have been located in Europe and North America (temperate zone). As a result we know most about the biodiversity in the temperate zone.
Where are most of the species that have been identified from?
Most of the species are in the temperate zone (about 2/3rds). This is because over the past few hundred years, most biologists have lived and worked in Europe or North America. So most of the species in the temperate zone have been identified but very few from the tropics have been identified.
Where is much diversity found in the rainforest?
Much diversity is found in the canopy level.
Why is it that we have discovered most higher taxonomic groups?
Now it is rare to identify a "new" phylum, class or order. Using the number of species identified for higher taxonomic groups we can predict how many species should be found on the planet. (The authors of this paper predicted around 8.7 million)
Why would people be interested in studying beetles?
One reason is that there are a ton of them. They make up 22% of all species. The great British biologist JBS Haldane once said, when asked whether studying biology had taught him anything about the Creator: " I'm really not sure except that He must be inordinately fond of beetles."
Who came up with the way to estimate the number of species using known to unknown faunas?
Peter Raven from the Missouri Botanical Garden!
What is some of the criticism of Erwin's study?
Scientists now believe that Erwin's estimate was too high. 1. Many of his assumptions have turned out to be incorrect- most importantly he probably overestimated the number of host specific beetles. 2. Methodologies that attempt to estimate global patterns from small areas are considered to be highly problematic. 3. Erwin's study (and others like his) are considered to be gross overestimates.
What are some other notable drug discoveries from natural products?
Taxol- breast and ovarian cancer. Lovastatin - cholesterol lowering drug Resperine - sedative Artemisinin - antimalarial Micafungin - antifungal
Describe the study of beetles in the South American rainforest.
Terry Erwin of the Smithsonian Institution also used the extrapolation approach to estimate biodiversity but he used a very different set of data. He attempted to estimate the number of species on the planet based on extrapolations from his studies of beetles in one location in Panama. He studied beetles in the canopy of the tropical rain forest of Panama.
What is the Sixth Mass Extinction?
The American Museum of Natural History surveyed biologists around the world and found that 7 out of 10 biologists believe we are currently in the midst of the 6th mass extinction of living things and that this dramatic loss of species poses a major threat to human existence in the next century. This is the fastest mass extinction in the Earth's 4.5 billion year history.
What is the Red List?
The International Union for Conservation of Nature (IUCN) produces a yearly red list of species at risk and a global assessment of the health of the worlds species every few years. These reports are used by governments and wildlife organizations to decide conservation-management strategies and funding allocation. Animals on the list could become extinct within the next several decades.
So why is it a problem that so many species are left to be identified and discovered?
The headlines regarding species and entire groups of organisms going extinct is a problem because we have no idea of what we are losing (since we don't know about them in the first place).
What is the historical background extinction rate and what does that mean of the rate today?
The historical rate is around 10-100 species per year. If 30,000 species per year are in fact lost we are well above the background extinction rate and are on our way to experiencing a mass extinction (75% of species lost). Note that it would take at least 360 years to catalogue all life by which more than half of all species will already be lost.
What is an example of a regulating ecosystem service?
The uptake of CO2 and subsequent regulation of climate.
Explain the domestication of dogs.
There are 100s of breads of dogs all are members of a single species Canis familiaris. The were domesticated from wolves in Asia some 10,000 years ago. Dogs represent an extreme example of the variation that can exist within a species that sometimes leads to confusion when identifying species.
What are the types of ecosystem services?
There are at least two types of ecosystem services - provisioning services - which involve the production of renewable resources - and regulating services - those that lessen environmental change.
Explain the example of the "classes" of vertebrates?
There are only 7 classes of vertebrate but more than 50,000 species of vertebrates have been discovered.
What is unique about African Elephants?
They are the largest land animal are highly gregarious and communicative. Females and young males live in cohesive herds of about ten related adults and their offspring. The matriarch, usually the oldest and largest female, sets the pace of the group's activities. Males leave herds at puberty, around their 13th year, and travel alone or in bachelor groups. Elephants travel widely in search of food. Movements vary depending upon food availability. African elephants communicate with rumbles, growls, bellows, and moans. Some of these varied, low frequency sounds may travel a mile or more.
What do Alomerus do?
They are tropical ants called Alomerus they build traps to catch insects. Ants wait in the trap or gallery with their mandibles sticking out when an insect walks over the trap they bite it and pull it against the trap. When this happens other ants swarm out stinging and killing the insect.
Explain our approach to estimating diversity.
We know significantly more about "higher" taxonomic groups than species. If the assignment of taxa to these higher groups follows a consistent pattern we can use this information to identify the number of species. For all known taxa, looked at how our awareness of taxonomic groups has changed over time. (Dr. Camilo Mora from the University of Hawaii)
What is mass extinction?
When extinction rates rise suddenly for a "short" period of time resulting in loss of 75% of species. Historically caused by natural disasters.
What was the fifth mass extinction caused by (at the end of the Mesozoic (cretaceous) period)?
the most recent mass extinction was at the Cretaceous- Tertiary boundary (65 Mya); 16% of families, 47% of genera of marine organisms, and 18% of vertebrate families were lost. Most notable was the disappearance of nonavian dinosaurs. Causes continue to be debated. Leading candidates include diverse climatic changes (e.g., temperature increases in deep seas) resulting from volcanic floods in India (Deccan Traps) and consequences of a giant asteroid impact in the Gulf of Mexico.
