Ecology Unit 5 Ch's 17, 21, 22
How many species are there?
1.3 million species have received Latin names, 15,000 new species are described each year, and estimates for the total number of species range from 3 to 100,000,000 most agree that there are about 10,000,000 species.
Describe the loss of diversity in domesticated species...
10% of all domestic bird breeds have gone extinct and another 21% are at risk. In 1900, farmers grew about 8000 varieties of apples, now only 100 are grown commercially. 80 to 90% of corn and wheat varieties are now extinct.
What is an Ecotone?
A boundary created by sharp changes in environmental conditions over a relatively short distance, accompanied by a major change in the composition of the species. Many species are adapted to each of the habitats but can also persist in the Ecotone. Ecotone's support a high number of species..."Ecotone fallacy".
What are food chains and food webs?
A food chain is a linear representation of how different species in a community feed on each other. A food web is a complex and realistic representation of how species feed on each other in a community. Arrows indicate the direction of movement of energy through food webs
What is a keystone species? Give an example...
A species that substantially affects the structure of communities despite the fact that individuals of the species might not be particularly numerous. Sea stars are a keystone predator in the intertidal zone predation keeps muscle species below K which limits interspecific competition.
Describe trophic cascade's...
A trophic cascade is when indirect effects in a community where effects from one trophic level have effects at multiple trophic levels above or below. A bottom up cascade is when the abundance is within trophic groups are determined by the amount of energy available from the producers in a community. A top down cascade is when the abundance within trophic groups is determined by the activity of predators at the top of the food web.
What are ecosystem engineers? Give an example...
A type of keystone species that substantially affects communities by changing the structure of the landscape. Beavers convert flowing streams into standing ponds, changing the community of plants and animals present.
Both species have intermediate...
Abundance
Species frequently exhibit a log normal distribution of...
Abundance
Describe direct effects on communities...
An interaction between two species that does not involve other species example predation.
Describe indirect effect on communities...
An interaction between two species that involves one or more intermediate species.
What are the three zones of communities along ocean shorelines?
Aquatic zone, intertidal zone, dry zone
Describe independence under harsh conditions...
At low elevation, removing neighbors increased survival and flowering which reduced competition. At high elevation, removing neighboring plants reduced survival and flowering, neighboring plants facilitate and interdependence of species was noted.
Human activities are causing the loss of...
BioDiversity
Communities can have distinct or gradual...
Boundries
Describe species re-introduction...
California condor population reduced to 30 by the 1970s. Entire wild population brought into captive breeding program. In 2019 there were greater than 500 condors. They were re-introduced into California, Arizona, and Mexico.
Describe climate change...
Climate change poses a major threat to species survival. Species may adapt to new conditions, shift geographic range. There are different effects on different species. Potential disruption of species interaction such as Polynesian. Effects of climate change will depend on how fast species can adapt and disperse, and how much we can limit climate change.
Describe habitat diversity and species diversity using birds and forests...
Communities with a higher diversity of habitats should offer more potential niches and higher diversity of species. Forests with more diverse foliage heights had greater diversity of bird species.
Describe the IUCN status of various taxonomic groups...
Conifers have around 50% of their species being either threatened or near threatened. Birds have 23% of their species being either threatened or near threatened. Reptiles have 28% of their species being either threatened or near threatened. Mammals have 32% of their species being either threatened or near threatened. Amphibians have 48% of their species being either threatened or near threatened. And finally fish have 28% of their species being either threatened or near threatened.
Describe corridors and connectivity...
Connecting fragments is important for maintaining dispersal and genetic diversity. Habitat corridors preserve small patches of habitat as steppingstones.
Describe the effect of habitat fragmentation on edge habitat using cowbirds...
Cowbirds or nest parasites. They live mainly in fields, but parasitize nests of forest birds. There is an increase in edge habitats in the southern United States forest which has allowed an increase in cowbird parasitism, and a decrease in population of parasitized species.
What is the effort called that is involved with protecting hotspots of biodiversity?
Critical ecosystem partnership fund
Describe changes in force cover...
Deforestation is still prevalent but some areas are re-growing forest.
Describe density mediated indirect effects with sea stars...
Density mediated indirect effect is an indirect effect caused by changes in the density of an intermediate species. Sea stars reduce the density of muscles in the intertidal zone and this allows other species like snails to occupy limited space on the rocks.
Describe snail density versus species richness of algae and the intermediate disturbance hypothesis...
Density of snails manipulated to vary intensity of disturbance through herbivores. Algal species richness was highest at intermediate levels of disturbance.
Describe serpentine soils...
Derived from weathering rock with high levels of nickel, chromium, and other heavy metals. Toxic to many plants species, but home to several serpentine adapted species. Sharp Ecotone between serpentine barons and adjacent forest community.
Describe independent species distribution along the moisture gradient in great smoky mountains...
Each species reaches peak abundance at a different point, species distributions appear independent of one another
The distribution of species around the world is also affected by...
Earth's history
Landscape ecology is the study of...
Ecological patterns and processes at large spatial scales.
Describe the effects of fragment size...
Flooded area behind a damn: hilltops became islands of habitat. Smaller islands cannot support populations of predators and there was an increase in herbivores. There was high mortality and low recruitment of tree saplings.
Communities are organized into...
Food webs
What are the examples of zones in communities of Cedar Glades?
Glade woods, and open Glade or flat rock
Describe the collapse of the Atlantic cod fishery...
Government regulates harvest; regulations must balance the benefit of conserving species with the economic benefits to humans. 1970s: new technologies allowed a large increase in the number of Atlantic cod caught off the coast of Newfoundland. Government proposed moratorium. Cod fisherman lobby the government keeps the fishery open; the cod population quickly crashed and 35,000 fisherman lost their livelihood. The government closed the fishery in 1992.
What four places describe the greater Yellowstone ecosystem?
Great prismatic spring, Yellowstone bison herd, grand Teton range, and Old Faithful geyser.
The equilibrium theory of island biogeography incorporates both...
Habitat area and isolation
Describe habitat fragmentation...
Habitat fragmentation is how human activities have caused fragmentation of once a continuous habitat. There is less total habitat, less core habitat, smaller patches of continuous habitat and more edge habitat
Describe human impacts on North American mammals...
Human impacts on diversity can be seen far back in time starting with the arrival of humans in North America around 11,500 years ago. Species area curves for the North American mammal fossils are observed an noted that there is less species richness with humans present. Arrival of humans coincided with a 15 to 42% decline in mammal diversity. Explanations for extinctions include climate change following glacial retreat, human hunting pressure, and epidemic diseases carried by domesticated animals.
Describe legacy effects of humans on the landscape...
Humans act as ecosystem engineers by constructing buildings, dams, irrigation channels and other things. Human activity causes habitat heterogeneity. Roman farms in France were abandoned in fourth century, there were higher calcium and phosphorus in the soil and greater plant species richness due to this import of building materials and non-native plant species.
Describe the loss of genetic diversity in crops...
Humans bred varieties that grew well under local environmental conditions. Modern farming practices such as irrigation and fertilizer reduced harshness of growing conditions and favored only top producing varieties.
Describe hump shaped distribution?
Hump shaped distribution is the most common. There is the highest diversity at intermediate productivity. Low productivity is where only very tolerant species can persist. High productivity is where most competitive species outcompete other species.
What explains the latitudinal gradient in species richness?
Hypothesis one: Poleward regions have experienced repeated cycles of glaciation. Tropical regions have not experienced glaciation. New species are continuingly arising over time. Tropical areas have had more time to accumulate species. Hypothesis two: The number of species in an area reflects an equilibrium between the processes of speciation and extinction. The higher number of species in the tropics as a result of higher speciational rates and lower extinction rates. Energy diversity hypothesis: sites with higher amounts of energy are able to support more species, and higher abundance of individual species. Lower rates of extinction, possibly higher rates of speciation. Potential evapotranspiration (PET): The amount of water that could be evaporated from the soil and transpired by plants given the average temperature and humidity. Provides an index of overall energy input into the environment.
Describe applying the theory to nature reserves using better design and worse design...
In better design the reserve size would be larger, the number as of reserves would be fewer, the reserve proximity would be closer, the reserve connectivity would be fully connected, and the reserve shape would be larger and more compound (circular). In worse design the reserve size would be small, there would be more numbers of reserves, the reserve proximity would be spread out, the reserve connectivity would have no connecting Corridor's, and the reserve shape would be spread like an oval.
The number of plant species will decrease if the number of added resources...
Increases
What structures communities?
Inter-dependent communities are communities in which species depend on each other to exist, the species interactions are ubiquitous such as mutualism or predator prey. Species composition of community should be predictable based on interactions and communities resemble super organisms. Independent communities are communities in which species do not depend on each other to exist so species presence and absence is based on abiotic tolerance of each species. Species composition may be unpredictable and can predict the pool of potential species, but not actual community.
What are the values of biodiversity?
Intrinsic value of biodiversity describes a focus on the inherent value of a species, not tied to any economic benefit. People who place intrinsic value on biodiversity feel religious, moral, or ethical obligations to preserve the worlds species. It is difficult to prioritize conservation efforts based on intrinsic values alone. Instrumental values of Bio diversity describes a focus on the economic value a species can provide example the value of lumber and crops . many species remain undiscovered so the value of species and ecosystems can be difficult to estimate . benefits of diversity are estimated at three hundred and nineteen billion dollars per year in the United States , and globally at three trillion dollars to fifty-four trillion dollars per year.
Describe the effect of island isolation...
Islands nearer to a source habitat should have higher colonization rights, greater number of species at equilibrium.
Describe landscape ecology...
It considers the spatial arrangement of habitats at different scales. Influences on individuals, populations, communities, and ecosystems. Current habitat heterogeneity is a reflection of recent and historical events caused by natural human forces.
What are mass extinctions?
It is estimated that 4 billion species have existed on earth; 99% of the species are now extinct. Constant speciational and extinction describes the background extinction rate. Mass extinction events describe events in which at least 75% of the existing species go extinct within a 2 million year period. Over the past 500, million years, the world has experienced five mass extinction events.
Describe species-area relationships...
It is the relationship between number of species and area: species area curve, and is linear when plotted on a scale. There was a survey of the wetlands in Ontario. Species area relationship slope is similar across different kinds of organisms and among different organisms habitats and scales slope tends to be .20-.35.
Although extinction is a natural process...
It's current rate is unprecedented.
Describe genetic diversity of domesticated species...
Little species diversity in domesticated species: humans predominantly rely on seven mammal species and four bird species: cattle, pigs, goats, sheep, horses, donkeys, buffalo and chickens, ducks, geese, and turkeys. Likewise, humans consume only about 150 species of plants. Just 12 species make up the vast majority of peoples diets example wheat, rice, beans, and corn.
Describe legacy effects...
Long lasting influences of historical processes on the current ecology of an area. Eskers are the remnants of streams of water that flowed inside glaciers. Deposited soil and rock on the stream bed and after the glaciers melted the streams appeared as long, winding Hills.
Describe indirect effects of insecticide on frogs...
Low concentration of the pesticide malathion do not harm leopard frog tadpoles so there is no direct effect but malathion reduced zooplankton which caused an algae bloom of phytoplankton that then shaded out Periphyton and decreased the food for leopard geckos.
Describe island biogeography on sky islands...
Mammal species that prefer Alpine habitats, mountain tops are analogous to oceanic islands, there is a similar effect of size in isolation so island biogeography can also be applied to habitat patches in terrestrial environments.
Describe habitat loss...
Many other habitats have changed as a result of human activities: tall grass prairie covered 69 million ha in North America; less than 4% remains. In the 1600s, wetlands covered more than 89 million ha in the lower 48 states; draining for human use has reduced this area in half. Habitat loss leads to fragmentation and smaller populations that are more likely to go extinct.
Describe patterns of marine bio diversity...
Marine species also show a general pattern of higher diversity near the equator. Also higher diversity in shallower coastal waters than in open ocean.
Describe ecological heterogeneity associated with less species diversity...
Marshes are highly productive, but relatively uniform which means there is lower diversity. Deserts have low productivity but are heterogeneous which results in higher diversity.
Describe patterns in north American diversity...
Most taxa show a pattern of higher richness farther south. East west pattern in mammals may be due to habitat heterogeneity in the mountains west. East west pattern in trees is likely due to the east west pattern and precipitation. Mammals cover North America, trees come second, reptiles come third, and amphibians cover the least amount.
Describe human influences on habitat heterogeneity...
Natural forces such as tornadoes hurricanes floods mudslides and fires continue to cause habitat heterogeneity. Human activity has influenced the intensity, frequency, and ecological influence of natural forces. Fire is a normal part of many ecosystems and fire suppression has resulted in buildup of fuel, more intense fires so fires generate habitat heterogeneity.
Biodiversity is highest...
Near the equator and declines towards the polls
Describe the bio geographic regions of earth...
North America is nearctic, South America is neotropical, Africa is Afrotropical, Europe and Asia are Palaearctic, India is Indomalayan, and Australia is Australian.
Describe overharvesting...
Overharvesting of species has resulted in population declines and extinction. Animal remains from archaeological sites in the Mediterranean suggests this has been occurring for a long time. Humans changed their diets as species became locally depleted. 1500 years ago, the arrival of humans on Madagascar caused the extinction of 14 lemur species and 6 to 12 species of elephant bird. Arrival of humans in New Zealand resulted in extinction of nine species of moa by 1300. Modern fishing techniques have increased the number of fish and shellfish caught. Overharvesting has led to an increase in the number of collapsed fisheries, or fishing areas that no longer have populations that can be finished. Collapsed fisheries occur in more than 25% of species assessed off the coast of north eastern United States.
Describe ecological heterogeneity such as soil's and plants associated with higher animal species diversity...
Plant diversity: grasslands have less and shrub lands which have less than Forest. In the surveying of breeding birds there were six species in grasslands, 14 species in shrublands and 24 species in Forest.
What is the rank abundance curve?
Plots the relative abundance of each species in a community and rank order from the most abundant species to the least abundant species. It illustrates species richness through the links along X axis and species evenness through the slope of the line.
Describe the park grass experiment which is been ongoing since 1856...
Plots were fertilized with different combinations of nutrients, added annually. Plots receiving more nutrients have lower number of grass species. At high nutrient levels, the most competitive grasses shade out other species.
Describe pollution...
Pollution can have a large effect on many species, especially at higher trophic levels. Biomagnification describes the process in which the concentration of a contaminant increases as it moves up the food chain. Biomagnification of DDT resulted in the declines of many predatory birds.
Describe the rank abundance curves in Lizard communities in primary forests verses plantations in Brazil...
Primary forest support higher species richness, but slightly higher evenness in plantations.
Describe protecting habitat...
Protecting habitat is probably the single most important conservation strategy. Amount of protected area continues to increase. 57% of countries have protected over 10% of their total area. The goal of habitat protection is to protect a minimum viable population of imperiled species. Minimum viable population MVP describes the smallest population size of a species that can persist in the face of environmental variation or The number of individuals that have an X percent probability of surviving Y years. Typically 95% probability of surviving the next 100 years.
Describe the values of biodiversity - instrumental values...
Provisioning services are benefits of biodiversity that humans use, including lumber, for, meat, crops, water, and fiber. Cancer drug Taxol was first derived from the Pacific yew tree greater than $1.5 billion in annual sales. More than 800 pharmaceutical chemicals have been derived from natural origins. Regulating services are benefits of biodiversity that include climate regulation, flood control, and water pollution. Supporting services or ecosystem services are benefits of biodiversity that allow ecosystems to exist such as primary production, pollination, soil formation, and nutrient cycling. Cultural services are benefits of biodiversity that provide aesthetic, spiritual, or recreational value such as hiking or camping. Income from tourist can exceed what would be received from clearing a forest or using land for housing or industry.
Describe global declines in genetic diversity...
Reduced genetic diversity can be caused by declining population sizes. Artificial selection and domesticated species has also reduced diversity. Low genetic diversity can reduce the probability that a population is able to survive changing conditions such as climate or emerging infectious diseases. Both wild and domesticated species have experienced loss in genetic diversity.
Describe reducing harvest...
Reducing or eliminating harvest of species may allow populations to rebound, even for long lived species. 100 northern elephant seals in 1900 now there are greater than 150,000. 440 S. Atlantic humpback whales in 1950s, now 25,000.
Species diversity is affected by...
Resources, habitat diversity, keystone species, and disturbance
What is an example of zonation of terrestrial communities in a mountain habitat?
Santa Catalina mountains, Arizona
Describe a sixth mass extinction?
Scientist have hypothesized increases in human population over the past 10,000 years has initiated a sixth mass extinction event. The United Nations convention on biological diversity estimates that the extinction rate over the past 50 years is 1000 times historic rates.
How do you reverse the effects of added nutrients?
Since fertilization decreases species richness. Light added to understory restores richness, even in fertilized treatment. This supports the hypothesis that under fertilization, competitive plants shade out others.
Conservation efforts can...
Slow or reverse declines in biodiversity.
Describe an experimental test of island biogeography theory...
Small islands in the Florida Keys fumigated to eliminate arthropods. Recolonization supports predictions of island biogeography.
Describe the effect of Island size...
Smaller islands should have higher extinction rates, lower number of species at equilibrium.
The value of biodiversity arises from...
Social, economic, and ecological considerations
Community diversity incorporates both the number and relative abundance of...
Species
Describe quantifying community diversity...
Species richness is the number of different species in a community. Absolute abundance is the number of individuals of an individual species in a community. Relative abundance is the proportion of individuals in a community represented by each species. Species evenness is a comparison of the relative abundance of each species in the community.
Describe habitat heterogeneity and species richness...
Species richness often increases from the Local to the landscape scale because habitat diversity increases along this gradient. Alpha or local diversity is the number of species in a relatively small area of homogeneous habitat. Ada diversity is the number of species that differ between two habitats. Gamma or regional diversity is the number of species in all of the habitats that comprise a large geographic area. Habitat heterogeneity results in high regional gamma diversity or regional species pool. Within the region, individual species tolerances result in a smaller number of species at any location or alpha diversity known as species sorting.
Describe the changing tree distribution following the retreat of glaciers...
Spruce moved north, Oak grew north, and Hemlock grew south and north but not in the middle.
Describe habitat loss in two species of primate...
The Sumatran orangutan has been losing its habitat since 1990. The golden lion tamarin has been losing its habitat since 1946 in Brazil.
What is the intermediate disturbance hypothesis?
The hypothesis stating that more species are present in a community that occasionally experiences disturbances than in a community experiencing frequent or rare disturbances.
Describe the map of protecting hotspots of biodiversity...
The islands of Micronesia and Polynesia and southern United States all the way through eastern and western South America, the edges of most of Africa, southern Europe and western Asia, southern Asia and the islands of Asia, and finally the edges of Australia are all red. The areas in red have greater than 1500 endemic plant species, but greater than 70% vegetation loss.
What was the continental drift?
The movement of land masses across the surface of the earth. Landmass location and connectivity have changed over earths history. Pangaea was in 250 Mya. Laurasia and Gondwana were in 100 Mya. N. America, S. America, Europe, Asia, India, Africa, Australia, and Antarctica are in 60 Mya.
Describe introduced species...
The number of introduced species has increased over time. Data on introduced species since 1900 for Nordic countries show more than 1600 species have been introduced to cross terrestrial, freshwater, and Marine ecosystems. Introductions of species can be both intentional and accidental. Only about 5% of introduced species become established in a new region, but those that do have a variety of affects. Some species provide important benefits such as the common honeybee; others can have negative effects on native species. Silver carp were introduced to control algae in aquaculture facilities. They have escaped and spread widely so they outcompete the native fish and now pose a hazard to boaters.
Describe the equilibrium model of island biogeography...
The number of species on an island reflects a balance between the colonization of new species and the extinction of existing species. On an uninhabited island, many species from a nearby source habitat could potentially colonized the island which results in a higher rate of colonization. The rate of new species colonizing the island declines as a function of how many species have already colonized the island. As more species colonize the island, species are subject to possible extension due to negative interactions such as competition, predation, and parasitism which results in increasing rate of extinction. Balance of colonization and extinction predicts an equilibrium number of the species island. It does not predict species composition. At equilibrium, constant turnover of species, but number of species are the same.
Describe island biogeography...
The number of species on an island reflects the area of the island, and distance to the nearest source of colonists.
Describe the line transect of serpentine and non-serpentine soils...
There are nine serpentine, 7 non-serpentine, and 12 overlap on the Ecotone but only three are actually adapted.
What is the Svalbard Global Seed Vault?
There is a concrete lined cave held at -18°C with a control room and each vault holds hundreds of boxes and each storage bag holds up to 500 seed packets, and each heat sealed aluminum foil packet contains approximately 500 seeds.
Describe the effect of habitat fragmentation on edge habitat...
There is less continuous core habitat and the edge habitat had different abiotic conditions such as higher temp or more light and there are changes in species composition relative to intact forest.
Describe the trait mediated indirect effects of herbivores on grass when spiders were present...
There was decreased herbivory. Grasshoppers alter feeding behavior in response to spiders.
Describe trait mediated indirect effects with wolves and elk...
Trait mediated indirect effect is an indirect effect caused by changes in the traits of an intermediate species. Reintroduction of wolves into Yellowstone national park resulted in the change in behavior of elk, less browsing in so many areas, rebound in three population, and increase in songbird diversity.
Describe trophic levels...
Trophic level is a level in the food chain or food web of an ecosystem. Producers formed the first trophic level of a food web. Primary consumers are a species that eat producers. Secondary consumers are species that eat primary consumers. Tertiary consumers are a species that eat secondary consumers. Omnivores are a species that feed at several trophic levels. A guild is within a given trophic level, a group of species that feeds on similar items such as leaf eater's; members of the group are not necessarily related.
Describe the different graphs that show affects of productivity on species richness...
U-shaped, negative which is a diagonal line pointing downward from the top, none which is a straight line going horizontally, positive which is a diagonal line pointing from the bottom to the top, and hump shaped.
Describe top down control...
When there are few tertiary consumers there will be more secondary consumers less primary consumers and more producers. When there are more tertiary consumers there will be less secondary consumers and more primary consumers which result in less producers.
Describe bottom up control...
When there are fewer producers with few primary consumers and a few amount of secondary consumers they will be a few amount of tertiary consumers. When there are more producers there will be more primary consumers and more secondary consumers which result in more tertiary consumers.
The number of species increases...
With increased geographic area
