Week 7 2003 Foundations of Biology

Who developed the organismic model? A. Daniel Simberloff B. Frederic Clements C. Henry Allan Gleason D. Joseph Connell E. E. O. Wilson

B. Frederic Clements

You decide to volunteer at a community garden and are assigned to tend six equally sized vegetable beds. Three of the beds contain only tomato plants, while the other three contain tomatoes as well as snow peas, bell peppers, cucumbers, okra, and broccoli. You work hard all summer and fall, tending the plants through grasshopper and leaf-footed bug outbreaks and severe summer storms with wind and hail. You harvest vegetables every three days and start to notice a pattern. The mixed vegetable plots consistently produce 4 pecks (a unit of dry goods measurement) each at every harvest, while the tomato only plots produce between 1-6 pecks each at every harvest. The garden director notices the pattern as well, and knowing you are a biology student, she asks you for an explanation. What concept or hypothesis do you cite in your response? A. The model of island biogeography B. The diversity-stability hypothesis C. The tolerance model D. The intermediate disturbance hypothesis E. The productivity hypothesis

B. The diversity-stability hypothesis

to qualify as a geographic biodiversity hot spot a region must meet what two criteria

1) must contain at least 1500 species of vascular plants as endemic 2) have lost at least 70% of its original habitat

The species richness of insects on trees can be predicted by which of the following? Check all that apply: 1. the time hypothesis 2. the evapotranspiration rate 3. the area hypothesis 4. the average body size of insects 2. the evapotranspiration rate3. the area hypothesis

2. the evapotranspiration rate 3. the area hypothesis

Ecosystem diversity 1 is the diversity of animal species within a defined geographical area. 2 is primarily associated with aquatic habitats. 3 refers to the structure and function within an ecosystem. 4 includes only species-rich ecosystems.

3 refers to the structure and function within an ecosystem

The model of island biogeography predicts that species richness will increase with decreasing distance from a species source pool. What do you think could be considered a source pool for a particular island? Select all that apply 1. Small, distant islands. 2. Communities undergoing primary succession. 3. The closest mainland area. 4. A nearby, larger island. 5. Species that have previously gone extinct on the island.

3. The closest mainland area. 4. A nearby, larger island.

Endangered species 1 will become extinct in the next 50 years. 2 are likely to be in danger of extinction in the future. 3 are those species found only in zoos, aquaria, and museums. 4 are mainly found in the tropics. 5 are in danger of extinction throughout all or most of their range.

5 are in danger of extinction throughout all or most of their range.

'Edge Effect'

Fragmentation negatively affects the quality of the habitat remaining

Why does biodiversity matter and what threatens it?

Habitat loss is the biggest single factor. Many species affected by more than one factor.

How does habitat loss occur?

Habitat loss typically occurs via fragmentation - an area is divided into multiple discontinuous fragments. -Conclusion: Biomass declines sharply along edges of forest fragments

Because biodiversity affects the health of ecosystems, ecologists have explored the question of how many species are needed for ecosystems to function properly. What variables were included in these models?

In doing so, they have described several possible relationships between ecosystem function and species richness.

Which hypothesis best describes the idea that a small decline in species richness results in a large drop in ecosystem function? Diversity-stability hypothesis Redundancy hypothesis Keystone hypothesis Idiosyncratic hypothesis Community hypothesis

Keystone hypothesis

According to the equilibrium model of island biogeography, which type of preserve would contain the most species? One large park Several small parks with a combined area equal to that of a large park Several small parks connected by a movement corridor A circular park All of the above

One large park

How do predators affect the population of their prey?

Predator aids competitive inferiors by selective grazing, raising community richness.

endemic species

Species that is found in only one area. Such species are especially vulnerable to extinction.

Why Preserve Biodiversity?

The conservation of biodiversity is urgent because, unlike other environmental problems, extinction is irreversible. • Humans are heavily dependent (ecologically & economically) on a range of ecosystem services provided by diverse communities (Table 60.1). - Ethical dimensions: is it fair for one species to dominate resources in such a way that drives tens of thousands of others to extinction? • More diverse communities are both more productive and resilient to disturbance.

What hypothesis did the Ecotron experiments display?

The redundancy hypothesis

Genetic diversity

The total genetic information contained within all individuals of a species (emphasis on capacity).

Species diversity

The variety of all the life-forms on Earth (emphasis on richness)

ecosystem diversity

The variety of biotic communities in a region, along with abiotic components such as soil, water, and nutrients (emphasis on functioning).

What statement is in accordance with the keystone hypothesis? a.Each species plays a small, but important role in the health of an ecosystem. b. The fewer species present in an ecosystem, the more stable the community. c. Only a few species contribute to the functioning of a particular ecosystem. d. The role of each species within an ecosystem is highly unpredictable.

a.Each species plays a small, but important role in the health of an ecosystem.

Idiosyncratic hypothesis

suggests that although ecosystem function can change as the number of species increases or decreases, the amount and direction of change are unpredictable

diversity-stability hypothesis

suggests that species-rich communities are more stable than those with fewer species. - If we use stability as a measure of ecosystem function, Elton's hypothesis indicates a linear correlation between ecosystem function and species richness; as the number of different species increases, ecosystem function increases proportionately

biodiversity crisis

the global elevated loss of species over the last several hundred years

According to the redundancy hypothesis, species are redundant if

they could be eliminated or replaced by others with no loss of ecosystem function.

What are movement corridors?

thin strips of land that permit the movement of species between preserved patches. -Such corridors ideally facilitate movements of organisms that are vulnerable to predation outside their natural habitat or have poor powers of dispersal between habitat patches. In this way, if a population in one small preserve experiences a disaster, immigrants from neighboring populations can more easily recolonize it. This avoids the need for humans to physically move new plants or animals into an area.

Conservation Biology

uses principles and knowledge from molecular biology, genetics, and ecology to protect and sustain biodiversity

The research conducted by Tilman and colleagues demonstrated that: as diversity increases, productivity increases. as diversity decreases, productivity increases. areas with higher diversity demonstrate less efficient use of nutrients. increases in species richness lead to an increase in invasive species. increased diversity results in increased susceptibility to disease.

as diversity increases, productivity increases.

The idea that humans have an innate attachment to other life-forms, put forth by E. O. Wilson, is known as biodiversity. biophilia. the call of the wild. biotheology. the "last of the wild."

biophilia

what shape park is preferable for minimizing edge effects

circular

Complete restoration

conservationists attempt to return a habitat to its condition prior to the disturbance

Megadiversity countries

countries with the greatest numbers of species

After being used for mining, what was once a deciduous forest is replaced by grassland to be used for public recreation. This process is known as complete restoration. rehabilitation. ecosystem replacement. bioremediation. habitat repair.

ecosystem replacement.

Biodiversity

encompasses the genetic diversity of species, the variety of species, and the different ecosystems they form. -all the organisms present on the 'tree of life'. • When biodiversity increases, branches and tips are added to the tree. • When extinctions occur, tips and perhaps branches are removed

Biodiversity hot spots are those areas rich in species. habitats. rare species. biodiversity. endemic species.

endemic specie

In 1977, Rafael Guzman, a Mexican biologist, discovered a previously unknown wild relative of corn that is resistant to many of the viral diseases that infect domestic corn. Agriculturalists believe that crossbreeding the wild corn with domestic corn could improve current corn crops. In this case, biodiversity is important at which level? ecosystem species genetic community both a and b

genetic

an indicator species

helps ecologists monitor the health of an area. The well-being of an indicator species reflects the well-being of the ecosystem.

Over time, dark forms of the peppered moth (Biston betularia) became more common in polluted environments because predators were less able to detect them on trees darkened by soot. These moths are regarded by many as a(n) keystone species. indicator species. umbrella species. flagship species. endangered species.

indicator species

an umbrella species.

is a species whose protection results in the protection of many other species as well.

an endemic species.

native to a particular habitat and only that habitat

Saving endangered habitats, such as the Argentine Pampas, focuses on: saving genetic diversity. saving keystone species. conservation in a megadiversity country. preserving an area rich in endemic species. preserving a representative habitat.

preserving a representative habitat

Captive breeding

propagation of animals and plants outside their natural habitat to produce stock for subsequent release into the wild - has proved valuable in re-establishing breeding populations following extinction or near extinction I.e falcons

Keystone hypothesis

proposes that ecosystem function dramatically rises as species richness approaches its natural level.

Biodiversity hotspots

regions that are biologically diverse and under threat of destruction -Conserving just 5% of land area would cover 65% of all plant species.

Ecosystem replacement

replaces original ecosystem with a different one ->useful in places in which the terrain has been substantially altered by past human activities

a flagship species.

single large or instantly recognizable species

a keystone species.

species whose community impact is large but disproportionate relative to its biomass

SLOSS

(for single large or several small).

What was were the arguments backing both sides of the SLOSS debate?

- According to island biogeography, a larger block of habitat should support more species than several smaller blocks. - However, many empirical studies suggest that multiple small sites of equivalent area will contain more species, because a series of small sites is more likely to contain a broader variety of habitats than one large site. Looking at a variety of sites, American conservationists Jim Quinn and Susan Harrison concluded that animal life was richer in collections of small preserves than in a smaller number of larger ones. In their study, having more habitat types outweighed the effect of larger area size on species richness. In addition, another benefit of a series of smaller preserves is a reduction of extinction risk by a single event such as a wildfire or the spread of disease.

In the Ecotron experiments of Shahid Naeem and colleagues, it was found that higher values of vegetative ground cover were correlated with: Check all that apply. 1 higher community productivity 2 lower nutrient uptake 3 increased decomposition rates 4 lower species richness 5 higher plant biomass

1 higher community productivity, 3 increased decomposition rates, 5 higher plant biomass

You discover a subterranean river in the outback of Australia and estimate that it is at least 50 million years old. You gather a crew of scientists to perform traditional species sampling of the river as well as metagenomics techniques to calculate microbial diversity. The results indicate that the river is extremely diverse - you even get to name a new species of shrimp after yourself! During one of your many interviews, you are asked to explain the high diversity of the subterranean river. What hypothesis would you cite? A. The time hypothesis. B. The area hypothesis. C. The productivity hypothesis. D. The intermediate disturbance hypothesis.

A. The time hypothesis.

In island biogeography, larger islands support ______ species than smaller islands.' A. more B. fewer C. larger D. more recently evolved E. more ancient

A. more

redundancy hypothesis

According to this hypothesis, ecosystem function increases rapidly at fairly low levels of species richness, but then levels off because most additional species are functionally redundant.

Rehabilitation

Aims to return the habitat to something similar to, but a little less than, full restoration

What did Tilman's plot experiments demonstrate?

Although Tilman's results show a relationship between species richness and ecosystem function, they also suggest that most of the advantages of increasing richness come with the first 5-10 species, beyond which adding more species appears to have little to no effect.

How Many Species Are Living Today?

Approximately 1.5 million species have been catalogued to date. - Only a tiny fraction of the number actually present. • Richness is not evenly distributed on Earth. - Tropical rainforests cover 7% of land surface but contain 50%.

Metagenomics offers a DNA-based method to understand A. the history of species diversity. B. microbial stability C. microbial diversity. D. the organismic model of communities. E. the Shannon Diversity Index.

C. microbial diversity.

How are species-area relationships traditionally plotted? A. on a log-linear plot B. on a bar graph. C. on a log-log plot D. on a linear plot E. as a function of distance

C. on a log-log plot

Types of habitat restoration

Complete restoration, rehabilitation, and ecosystem replacement

What are some disadvantages of movement corridors?

Corridors also can facilitate the spread of disease, invasive species, and fire between small preserves.

What biome has conservation mainly focused on?

Tropical rain forests->species rich ecosystems

Reproductive cloning

Used to clone endangered species

Reintroductions

Valuable conservation strategy that can re-establish populations in areas where they once occurred

Which of the following best describes an endangered species? a species that is likely to become extinct in a portion of its range a species that has disappeared in a particular community but is present in other natural environments a species that is extinct a species that is in danger of becoming extinct throughout all or a significant portion of its range Both b and d are true of endangered species.

a species that is in danger of becoming extinct throughout all or a significant portion of its range