The Big Picture

The concern for global biodiversity has only recently begun to move toward center stage as an international issue. Biodiversity conservation was a central theme at the U.N. Conference on Environment and Development, Rio de Janeiro, 1992 (The Earth Summit). Part of the delay in recognizing the problems facing global biodiversity stems from the fact that relatively little is known about global and, in many cases, even local biodiversity. The number of species of plants, animals, fungi, protists and other microbes that have been taxonomically classified is approximately 1.4 million. But, many eminent scientists who have spent most of their careers studying global biodiversity agree that there are vastly more species that have not been identified; some estimates range as high as 100 million species. Species diversity is only one aspect of biodiversity. Genetic diversity and ecosystem diversity as well as species diversity are components of biodiversity. The diversity of life is a consequence of over 4 billion years of evolution. The winnowing process of natural selection has selected for certain characteristics that allowed species to survive in a given environment, while eliminating those characteristics that were not as favorable. Through evolutionary time, species extinction has been commonplace. In recent years, however, species extinction rates have been greatly accelerated by human activities, primarily land alteration and ecosystem fragmentation, pollution, and over harvesting. Much has been learned about species extinction and replacement from studying populations on ecological islands. For the global ecosystem, however, there are no replacement species to balance those being lost due to extinction. The science (and art, as some propose) of restoration ecology is still in an early developmental stage. No amount of biodiversity restoration can keep pace with the losses that are now occurring. But, through a combination of preservation, conservation and restoration partial recovery of damaged ecosystems may be possible.
 
 

Frequently Asked Questions
 
 

What is biodiversity?

• The word "biodiversity" has only been in usage for a short time. Coined by E.O. Wilson in 1982, "biodiversity" has become an often-used term within the scientific community and beyond.
• Biodiversity is an expansion of the concept of species diversity by incorporation of diversity both above and below the species level. Thus biodiversity has three components:
• Ecosystem diversity is a measure of the complexity of an ecosystem, for example measuring the number of trophic levels or trophic connections in an ecosystem.
• Species diversity or species richness is a measure of the number of different species in a community.
• Genetic diversity is a measuring of genetic variation within species populations.
• Biodiversity (and all of biology, for that matter) must be conceptualized within an evolutionary framework. Evolution is the common thread of the natural sciences.

• This is one of the most fundamental questions of biology.
• It is a fact that life has evolved; it is a fact that natural selection is the mechanism of evolution; it is also a fact that the intricacies of this complex process called evolution are not entirely understood.
• Natural selection, the process by which life evolved, was explained by Charles Darwin in the 1859 publication, On the Origin of Species By Means of Natural Selection.
• Alfred Wallace simultaneously and independently developed the concept of natural selection but did not receive the notoriety attributed to Darwin.
• The concepts of microevolution and macroevolution can be used to present a simplified explanation of evolution and natural selection.
• Microevolution is the change in the genetic characteristic of a gene pool over time. A gene pool is the total genetic information within a population. Changes (variation) in gene pools come about by a number of reasons:
• Mutations which occur at the gene and chromosome level.
• Populations migrate into new habitats with new selective pressures.
• Genetic drift (changes in a gene pool resulting from chance alone) which is most significantly expressed in small, isolated population. Sexual reproduction introduces a myriad of possible variations.
• Macroevolution or speciation is the accumulation of sufficient microevolutionary changes to result in the divergence of new species.
• Species may be defined as "a population whose members are able to interbreed freely under natural conditions" (E.O. Wilson, The Diversity of Life).
• Natural selection is the primary process by which macroevolution occurs.
• The basic tenets of natural selection are:
• Genetic variability (expressed as traits) a result of random genetic combinations exists within populations.
• Selective pressures are imposed upon populations by their environment.
• Some variants possess characteristics that enhance their survival and reproductive ability; they are selected for by their environment. Thus there is differential reproduction.
• Those individuals that have been selected for, are more successful in passing their genetic characteristics on the next generation. The genetic characteristics of individuals that have been selected against are eventually removed from the population.
• It is important to understand that selective pressures change as environmental conditions change. For example, the introduction of new predators or changes in climatic conditions, exert new selective pressures and drive the process of natural selection.
• Biological and evolutionary success is getting one's genes into the next generation. This is how species win at the "game of evolution."

• Darwin postulated that species evolve slowly with many intermediate forms between extant (living) species and extinct ancestral species; this is called gradualism.
• S.J. Gould and N. Eldridge proposed an alternative explanation called punctuated equilibrium. They proposed that evolution from ancestral species to extant species is characterized by alternating episodes of rapid divergence followed by long periods of stability with little speciation.

• Biologists and geologists use the geologic time scale to categorize the major events of in the evolution of life by date.
• The geologic time table is divided into time units based on major events that have been preserved in the fossil record. The major events used to divide the geologic time scale are events of rapid speciation (radiations) and mass extinction that have been recorded in the fossil record. For example, the extinction of the dinosaurs 65.3 million years ago marks the end of the Cretaceous and the beginning of the Tertiary time periods.

• Species richness is a count of the total number of species in the area under study (Figure 7.3). Richness is expressed as a single number.
• Species evenness is a measure of the relative abundance of the species in the area under study. Evenness is expressed as a percentage.
• Species dominance is a more difficult concept. Dominance may be measured in several ways; numerical dominance, biomass, coverage, ability to amass resources, or a combination of parameters, such as, species relative abundance, relative frequency (number of times a species is encountered in a survey), and coverage.
• There are several species diversity indices (mathematical equations such as the Shannon Index) used by ecologists, but alone, they will not provide an adequate assessment of diversity. Species diversity should be expressed in combination with species richness and evenness, as well as the Shannon Index.

• The number of species that have been described taxonomically (given a genus and species name) stands very roughly at 1.4 million (Table 7.1).
• Far more species have not been taxonomically described. Projections by E.O. Wilson of the number of these undescribed or unknown species ranges to 10 million or 100 million.
• Certainly some taxonomic groups are well-described and well known. The number of bird species and the number of mammal species are quite precise; few new species in these groups are likely to be discovered.
• Other groups, such as insects, the most species rich taxonomic group with over 750,000 known species, are still a poorly described. The least described and most difficult to classify are microbes, of which the species diversity cannot be estimated with any reasonable degree of reliability.

• Exotic species, or non-native species, are species that have been introduced into a new geographical area.
• Endemic species, or native species are species native to a specific area.
• The term "exotic species" has often been misused to describe species with striking appearances or unusual behaviors. For example, toucans are certainly striking in appearance but they are not exotic to the forests of Central America, they are endemic. Toucans that escape from captivity in south Florida are truly exotic.
• In many instances, exotic species become pest species by out competing or preying upon endemic species. Hawaii, Florida and California have experienced major ecological problems with exotic plants and animals that have been introduced by humans.
• Cosmopolitan species are found worldwide, wherever the appropriate habitat exists.
• Ubiquitous species are found almost everywhere, worldwide, in a range of habitats.

• Interactions between individuals of the same species are called intraspecific interactions. Intraspecific interactions include competing for food, mates, space, and territories, as well as mutual defense and other cooperative behaviors.
• Interactions between individuals belonging to different species are called interspecific interactions (Table 7.2). Interspecific interactions include competition for resources (e.g., food, water, and space), symbiosis (i.e., mutualism), and predation-parasitism.
• Both intraspecific and interspecific interactions play major roles in natural selection evolution, and overall diversity. Intraspecific and interspecific interactions are central themes is the science of ecology.

• When two species compete for the same resources, the resources become depleted and both species are affected detrimentally. However, no two species exploit resources quite the same way, one species will be able to exploit the available resources better that the other.
• This is basis for the competitive exclusion principle; two species that have the same requirements cannot coexist in exactly the same habitat. Thus, one species will exclude the other.

• Species coexist by exploiting the available resources in a sufficiently different manner such that competition is avoided or reduced and coexistence is possible.
• Thus, each species has a different ecological niche, which may be defined as the species' functional position in its habitat (how it interrelates with its environment and other species within its environment).
• By each species having a separate niche, many species are able to coexist and share resources in the same community.

• The niche occupied by a species may be quantified if the environmental conditions under which the species lives and the resource base of the species are known.
• For simplicity, one environmental parameter can be measured at a time, for example, the temperature range in which a species (a freshwater flatworm) survives (Figure 7.6). In the case of flatworm "a", if no competing species are present, the worm has a relatively broad niche width; this is its fundamental niche. In nature, however, other species may be better competitors under certain conditions. The niche of flatworm "a" is reduced in size by the presence of a competing species, flatworm "b". This reduced niche width is the realized niche.
• The ecological niche of a species cannot be adequately determined by a single parameter, all of a species requirements must be accounted for.
• Some species have broad niche widths. These species are generalists, capable of exploiting a variety of resources in a variety of ways. A good generalist species is the coyote, a carnivore that eats insects, birds, reptile, mammals, and carrion, and lives in a great variety of habitats.
• Some species, specialists, have narrow niches; that is they are highly specialized to exploit their environment in a very precise manner. Specialists have few options if changes occur in their environment. The ivory-billed woodpecker was a specialist. This large bird required old-growth swamp forests in the southeastern U.S. Most of these swamp forests were logged a century ago; consequently the ivory-billed woodpecker is now extinct.

• "Symbiosis" means living together. Many symbiotic relationships are beneficial to both symbionts, this is called mutualism. Parasitism is also a symbiotic relationship but the host is affected detrimentally.
• Examples of mutualistic symbiosis are commonplace. Bees pollinating flowers benefit both species; specialized fungi living in association with plant roots and facilitating nitrogen-fixation; and microbes (microflora) living in the gut of ruminants and other animals (including humans) facilitate digestion and assimilation (Figure 7.7).
• Symbiotic relationships exist because the symbionts coevolved. Coevolution is the complementary evolution of two or more species, each species affecting the evolutionary course of the other. Coevolution occurs in predator-prey relationships and well as symbiotic relationships.

• Predators exert a strong influence on the abundance of prey populations. Predators keep prey populations in check thereby limiting the size of the prey gene pool and prevent a single or a few prey species from dominating the community.
• In many predator-prey relationships, predators selectively remove the poorly adapted individuals from the prey population, thus driving natural selection.
• Conversely, the size of the prey population influences natural selection in predator populations. If prey populations are low, only the best-adapted predators will survive.

• In general, low latitude environments (tropical) are higher in biodiversity than higher latitude environments (more temperate or polar). Similarly, low elevation environments have a higher diversity than high elevation environments.
• Altitudinal ecological gradients resemble latitudinal gradients (Figure 7.9). For example, the base of Mt. Kenya is situated in a tropical savanna but the top of the mountain is tundra and glacier, even though the latitude is less than 50 km south of the equator.
• Although species richness may be low in high latitude areas, the abundance of individual species can be high. For example, in the world's most productive commercial fishing ground in mid-to-high latitude oceanic regions, the catch may consist of only a handful of species but many tons of those species. Whereas a tropical coral reef has numerous fish species but no single species is in great abundance.
• There are many theories to explain global biodiversity. These theories have been condensed and summarized into a set of factors listed in Table 7.3.
• In general, biodiversity is highest in areas of complex habitat (e.g., a tropical rain forest with multiple forest strata or layers), high productivity, stable climate, moderate disturbance, mid-succession, and where evolution has been allowed to proceed uninterrupted by major climatic or geologic upheavals for a long period of time.
• Biodiversity is lowest in areas of extreme stress (Figure 7.14), extreme physical environment, severely limited resources, frequent and/or intense disturbance, geographic isolation, and where exotic species have been introduced.

• Biogeography examines the global distribution patterns of living things.
• Biogeography, as a scientific endeavor, came into its own during the nineteenth century when European explorers traveled the globe cataloging natural history observations for scientific as well as economic reasons. Alexander von Humboldt, whom the Humboldt Current and Humboldt County California are named after, and Andreas Schimper, who coined the term "rain forest" are but two of these explorers.
• Biogeographers use any of several classification schemes to categorize global biodiversity.
• Biogeographic realms are based upon evolutionary relationship and morphological similarities of animals (Figure 7.11). Alfred Wallace divided the world into six biogeographic realms: the Nearctic, Neotropical, Palearctic, Ethiopian, Oriental, and Australian.
• The concept of the biotic province is an expansion of the biogeographic realm to include plants (Figure 7.12).
• Biomes (see Chapter 9) are based upon the growth forms of vegetation in response to climatic conditions (Figure 7.16). Climatic conditions (temperature and moisture regime) determine plant physiology and morphology (Figure 7.15). There are at least nine biomes (ten listed by your author): tundra, taiga, temperate forest, temperate rain forest, temperate woodland, temperate shrubland, temperate grassland, tropical rain forest, tropical seasonal forest and savanna, and desert.

• Convergent evolution is the evolution of similar morphologies in unrelated (or distantly related) organisms. Convergent evolution occurs as different species adapt to similar environmental pressures. For example, fish, whales, and ichthyosaurs (aquatic dinosaurs) each evolved similar morphologies (fins and tails) for swimming.
• Divergent evolution is the evolution of new species from a common ancestor (Figure 7.17). Geographic isolation (and subsequent genetic drift) is a primary cause of divergence. It is assumed that all bird species diverged from a common ancestor, Archaeopteryx.

• Islands may be considered microcosms, from which studies of global biogeography, biodiversity and evolution may be extrapolated.
• Ecological islands are not only bits of land in the ocean, but any isolated habitat could be considered an island. For example, in the Southwest, conifer forests on isolated mountaintops are isolated from other mountain top conifer forests by desert valleys.
• Islands have fewer species than mainlands, and islands have fewer resources than mainlands.
• Islands have high endemism (unique species). One reason for this is adaptive radiation. In order to reduce competition for the limited resources on islands, new species diverged from ancestral species to fill unoccupied niches. The adaptive radiation of Darwin's finches in the Galapagos Islands or honeycreepers in Hawaii (Figure 7.18) are often-cited examples. In terms of species diversity on islands, two aspects of islands are most important; island size and isolation (Figures 7.19 and 7.20).
• Based on studies of island biogeography, the following generalizations may be made:
• Small islands have lower species diversity than large islands. Small islands are small targets for potential colonists and small islands can support a limited number of individuals. Extinction on small islands is more likely.
• Distant islands have lower species diversity than nearby islands. Distant islands are more difficult to colonize than nearby islands.
• Species richness on islands is constant. The species composition may change as one species replaces another but the total numbers of species stays the same. New arrivals either will not become successfully established or they will replace species already on the island.
• The lessons learned from studying biogeography are very important if we are to develop a better understanding of global biodiversity, species extinction, and changing landscapes.
• The fragmentation of the landscape by agriculture, forestry, and urbanization creates ecological islands. Many species that require large tracts of unaltered habitat cannot survive in small patches thus face extinction.

• Calculate the Shannon diversity index and "species" richness for cars in a parking lot. Diversity indices are typically used to measure species diversity in nature, but, just for fun, you could calculate a "diversity index" for cars in a parking lot!
• The calculations of species diversity, evenness, and richness are the same (see equations and example data set below).
• This kind of inter-community comparison is done by ecologists attempting to assess the impacts of human development or pollution. When pollution is present or a human disturbance has occurred in an ecological community, diversity is typically low.
• Example of calculating species diversity in two parking lot "communities":
• Count the number of individuals of different "species" of cars in each parking lot "community".
• The number of "species" or car types in each lot = S
• First, calculate relative abundance (p_i) for each "species" in each "community" (i.e., the proportion of the "community" represented by each "species" i):

Where:

n_i = number of "individuals" in "species" i,

• Next calculate the Shannon Diversity Index :

• Let us break down each part of this equation:
• The "sigma" is a summation sign  , which means that you should perform  the operations inside the [x] for each species i, starting with species i = 1 and stopping when i = S.
• The quantity [x] is in this case [p_i(ln(p_i))].
• First, the relative abundance p_i  should be calculated for each species i in the community (see above). Write them down in a table.
• Next, a calculator with a ln (or natural log) function can be used to obtain the quantity (ln(p_i)), which is the natural log of the relative abundance.   Alternatively, one can use a table of natural logs (Note that because all p_i will be less than 1.0, we only need a table showing p_i between 0.0 and 1.0, and at 0.1 intervals):

• Add the result inside [x] the for the first species to the result inside the for [x] the next species, and so on, and stop when you get to the last species, i = S.
• Note that there is a negative sign before the summation sign  in the H' equation, which means that your answers will always be positive.  This is because the quantity after the summation will always be negative.
• Here's an example data set:

"Species" of Cars	"Species" identifier code i	Number of "individuals" in Parking lot A ni	pi	ln (pi )	pi (ln (pi ))
Chrysler Lebaron	1	20	0.20	-1.609	-0.322
Dodge Minivan	2	20	0.20	-1.609	-0.322
Toyota Corolla	3	20	0.20	-1.609	-0.322
Chevy Cavalier	4	20	0.20	-1.609	-0.322
Nissan Pickup	5	10	0.10	-2.303	-0.230
Ford Taurus	6	10	0.10	-2.303	-0.230
TOTAL	S= 6	N = 100	1.00		= -1.748

• Which parking lot "community" above is most diverse?  Both parking lots have the same number of "species", and thus are equal in the diversity from the standpoint of species richness S.  This is why we need to use a sort of tie-breaker, the Shannon index of diversity H'.  Lot A  has a H' = 1.748.  The car "species" are nearly equally represented in this lot. We say that this "community" has a high degree of evenness. Lot B is less diverse based on our index (H'= 1.695) and has lower evenness, because the car "species" are more unequally represented.  Chevy Cavaliers are the most common "species" in Lot B, followed by Nissan Pickups and Ford Tauruses. This lot has a high degree of dominance by these three "species" ( p₄ + p₅ + p₆ = 0.70, or 70 % of the individuals in this community are Chevys, Fords and Nissans).

• Now, collect your data outside in a real parking lot!
• Choose a safe parking lot, preferably one without much immigration and emigration (cars coming and going) and record the number of cars by "species", i.e., their manufacturer (e.g., Ford, Chevrolet, Toyota, or Ferrari).
• Diversity indices are used for comparative purposes, so compare your parking lot with another parking lot, for example, a faculty vs. a student parking lot, or compare the same parking lot at different times. Which car "species" is the most common, or dominant "species", in each lot?
• If you compared the student lot to a car dealer's lot, which one would show the greatest diversity in types of cars? The car dealer's lot would be characterized as a low diversity "community", while the student lot would have more "species" of cars, and would thus be considered high diversity.
• Remember to count the number of "individual" cars in each "species" and enter that number in the third column on the data sheets that follow.
• Use a calculator with a ln function to calculate the remaining two columns, and add up the negative values in the last column. Multiply the sum by -1 and you have calculated H'.
• You may want to group similar vehicles like "Ford pick-up trucks" or "Chevy sedans" into a single "species".
• Do not worry if the car "species" list differs somewhat between "communities".
• Sample at least 100 cars in each of the lots you survey.

• Birding is an excellent and fun way to learn about biodiversity. Additionally, birds are good indicators of habitat conditions; many bird species are very specialized with strict habitat requirements.
• Tracking migratory bird populations is especially important and highlights the need to address environmental issues on an international level. Migratory bird habitats must be maintained over a very broad area. It is not sufficient to maintain habitats at one end of their migratory route and not at the other.
• You do not need to take a course in ornithology or belong to a club to take up birding. A good pair of binoculars and a field guide to birds constitutes the basic equipment. The National Geographic Society, the Peterson Field Guide series, and the National Audubon Society series produce popular field guides for North American birds. Keep a journal of your observations.
• Calculate the species diversity of the bird community in your local area. Compare diversity in different areas.

• Please respond to these questions or send your thoughtful examples and comments to:

• Darwin, C. 1859. The Origin of Species. Murray, London.
• Dawkins, R. 1989. The Selfish Gene. Oxford University Press, New York.
• Goodall, D.W. (editor in chief). 198- . Ecosystems of the World. Elsevier, Amsterdam. A series of over twenty books covering the major ecosystem on the planet.
• Gould, S.J. (ed.). 1993. The Book of Life. W.W. Norton, New York.
• Hilty, S. 1994. Birds of Tropical America: A Watchers Introduction to Behavior, Breeding and Diversity. Chapters Publishing Company, Shelburne Vermont. 304 pp.
• Rosenzweig, M.L. 1995. Species Diversity in Time and Space. Cambridge University Press, New York.
• U.S. Fish and Wildlife Service. A Community Profile series published as FWS/OBS- documents published in the 1980's -1990's covering a broad range of ecosystems.
• Ward, P. 1994. The End of Evolution: A Journey in Search of Clues to the Third Mass Extinction Facing Planet Earth. Bantam Books, New York. 301 pp.
• Wilson, E.O. 1992. The Diversity of Life. W.W. Norton Company, New York. 424 pp.

• http://home.navisoft.com/entisoft/origspec.htm#c0 - Origin of Species, the complete text of Darwin's pivotal book.

• http://www.terraquest.com/galapagos/wildlife/evolution/evolution.html - Darwin and natural selection are discussed at this web site. Also see Darwin's finches at: http://www.terraquest.com/galapagos/wildlife/island/finch.html

• http://phylogeny.arizona.edu/tree/phylogeny.html - The Tree of Life Project This University of Arizona web site allows you to explore biodiversity based on phylogenetic relationships and characteristics of organisms.

• http://www.erin.gov.au/life/general_info/op1.html - The value of biodiversity is discussed at this Australian Department of Environment, Sport and Territories web site. For a discussion of habitat fragmentation see: http://www.erin.gov.au/life/general_info/biodivser_6/bioch2.html

• http://www.aqd.nps.gov/natnet/wv/exotics.htm - The National Park Service policy statement on exotic species is presented at this web site. To read the NPS exotic plant management strategy see: http://www.aqd.nps.gov/natnet/wv/strat_pl.htm

• http://www.unep.ch/bio/conv-e.html - The U.N./Convention on Biological Diversity - an overview if biodiversity is presented. (See the explanatory leaflet.)

• http://www.inbio.ac.cr:80/infoi.html - Costa Rica's INBio (Instituto Nacional de Biodiversidad) Costa Rica is a leading nation in efforts to protect its biodiversity; however, deforestation in unprotected areas is on-going.

• http://www.jrc.es/~beese/nat-prod.htm - Biodiversity prospecting - Merck, a leading pharmaceutical company is also a leading company in biodiversity prospecting.

• http://www.rbgkew.org.uk:80/seedbank/msb.html- A genetic conservation program (seed bank program) at the Royal Botanic Gardens, Kew.

• http://www.kilimanjaro.com/kenya/mtkenya.htm - Mount Kenya; changes in vegetation with increases in altitude at Mt. Kenya.

• http://www.netlink.co.uk/users/aw/nbchome.html - Neotropical birds and their decline are discussed at this Neotropical Bird Club web site.

• http://nabalu.flas.ufl.edu/ser/SERhome.html - The Society for Ecological Restoration web site provides information about ecosystem restoration. (See the Environmental Policies section.)

• http://www.amfor.org:80/dirt.html - Global Releaf is an environmental organization dedicated to planting trees in urban as well as rural landscapes.

• Note: If any of these links are not working, please see if alternative links are available at the Ecolink Update Site.

Ecotest Online
 
 

1. "Biodiversity" incorporates the diversity of life at three levels, which one of the following is not one of those levels?

a. species diversity

b. genetic diversity

c. ecosystem diversity

d. trophic diversity
 
 

2. The concept of natural selection, was simultaneously but independently developed by Darwin and ______.

a. Wallace

b. Hutton

c. Huxley

d. von Humboldt
 
 

3. Changes in the gene pool of a population constitute _______.

a. macroevolution

b. adaptive radiation

c. microevolution

d. intraspecific interaction
 
 

4. All of the following are tenets of natural selection except:

a. the Hardy-Weinberg equilibrium must be maintained

b. genetic variability exists within populations

c. selective pressures are imposed by the current environment

d. differential survival and reproduction influences future gene pools
 
 

5. Darwin proposed that the rate of evolution was gradual with many intermediate forms (gradualism); Gould and Eldridge proposed that evolution occurs in alternative stages of rapid speciation followed by relative stability, this is called _______.

a. macroevolution

b. dynamic response

c. punctuated equilibrium

d. intermediate disturbance
 
 

6. Species ______ is a count of the number of species in a given area.

a. dominance

b. frequency

c. richness

d. evenness
 
 

7. In the Florida Keys, the Australian pine has become a pest species. This non-native tree species was introduced decades ago and now is a dominant feature of the landscape, displacing native species. In Florida, the Australian pine is a(an) __________ species.

a. pandemic

b. ubiquitous

c. exotic

d. endemic
 
 

8. The ________ principle states that two species that have the same requirements cannot coexist in the same habitat.

a. competitive exclusion

b. niche inhibition

c. interspecific competition

d. realized niche
 
 

9. Ecosystems with high biodiversity tend to have one or more of the following characteristics, except _______, which is a characteristic of low biodiversity ecosystems.

a. stable climate

b. intermediate frequency and intensity of disturbance

c. complex habitat

d. high latitude
 
 

10. Which of the follow islands would be expected to have the highest biodiversity?

a. a large island far from the mainland

b. a small island far from the mainland

c. a small island near the mainland

d. a large island near the mainland