Conservation Biology Test 1

What determines the number of species in temporal patterns of biodiversity?

The dynamic equilibrium between speciation rate and extinction rate.

Have speciation and extinction rates remained constant over geologic time?

No; they have varied over geologic time.

From what source are rates estimated, and what bias exists in that source?

From the fossil record, which is always incomplete and biased toward the present.

Which group is best represented in the fossil record for estimating rates?

Hard-shelled marine invertebrates.

What is the Cretaceous–Tertiary boundary age?

Approximately 65 million years ago.

When did the Cambrian explosion occur?

Around 542 million years ago.

Name the five major mass extinction events listed in the notes.

End-Ordovician, Late Devonian, End-Permian (the biggest), End-Triassic, End-Cretaceous.

Which extinction is commonly associated with the demise of the dinosaurs?

End-Cretaceous (K-Pg boundary).

What caused the End-Permian mass extinction?

Volcanism and associated climate change and changes in ocean chemistry.

What caused the End-Triassic mass extinction?

Volcanism.

Which recent extinction is associated with humans?

Holocene (contemporary) extinction.

Name three factors correlated with high speciation rates in temporal patterns of biodiversity.

1) Radiation into vacant niches after mass extinctions; 2) Geographic isolation from continental separation; 3) Evolution of new body plans or new interactions.

What is the significance of Pangaea in terms of geographic isolation?

Pangaea's breakup created Laurasia and Gondwana, promoting isolation and speciation.

What are the two major landmasses that formed from the breakup of Pangaea?

Laurasia and Gondwana.

What is an endemic?

A species restricted to a single region or geographic area (e.g., an island).

Islands typically have lower species richness but higher endemism. True or false?

True.

Define alpha, beta, and gamma richness.

Alpha: number of species at a given site; Beta: rate of change in species across sites; Gamma: number of species in a region; beta = gamma / mean alpha.

What does the Amazon Basin example illustrate about alpha richness?

High alpha richness is associated with the presence of many rare species.

What is the latitudinal gradient in biodiversity?

A strong gradient with greater species richness in the tropics than in temperate zones.

Name the main hypotheses proposed to explain the latitudinal gradient in species richness.

Time/stability hypothesis; Species-area hypothesis; Species-productivity hypothesis (and their modifications).

What is the species-productivity relationship?

Species richness increases with productivity (biomass); productivity is driven by solar radiation and precipitation terrestrially, and by upwellings in marine systems.

State the species-area relationship and what each symbol represents.

S = c*A^z, where S is the number of species, A is area, and c and z are constants.

What is the typical range for the exponent z in the species-area relationship S = c*A^z?

Approximately 0.20 to 0.35.

What factors contribute to the species-area relationship besides area alone?

Increased area leads to more habitat heterogeneity and larger populations, reducing extinction and increasing genetic diversity and potential speciation.

What does the intermediate disturbance hypothesis state about species richness?

Species richness peaks at intermediate levels of disturbance.

What happens to species richness under very high disturbance?

Only a few species can survive.

What happens to species richness under very low disturbance?

A few competitively superior species drive others to extinction, reducing diversity.

What is a biome?

A large, relatively distinct terrestrial region with similar climate, soil, plants, and animals.

Biomes are mainly recognized by which feature?

Dominant vegetation type.

How many terrestrial biomes are recognized?

10–20.

Biome type at a location is determined by which two factors?

Temperature and precipitation.

What is Latitude?

The angular distance of a place north or south of the earth's equator.

Name three biomes listed on the World biomes map.

Tundra; Boreal forest; Desert and dry shrubland.

Tundra characteristics?

Treeless; dominated by lichens and small plants; permafrost; cold; dry growing season; low species richness and low primary productivity.

Boreal forest characteristics?

Dominated by coniferous trees; cold; dry growing season; low species richness; low primary productivity.

Temperate deciduous forest characteristics?

Dominated by deciduous trees; moderate temperature and precipitation; moderate growing season, species richness, and productivity.

Temperate grassland characteristics?

Treeless; dominated by grasses; moderate precipitation; moderate growing season and productivity.

Chaparral characteristics?

Dominated by small trees and evergreen shrubs; moderate temperature; dry growing season; moderate species richness and productivity.

Desert characteristics?

Drought-tolerant plants; hot or cold; low precipitation; short growing season; low species richness and productivity.

Tropical rainforest characteristics?

Dominated by broad-leaved evergreen trees; warm; high precipitation; long growing season; high species richness and productivity.

Savanna characteristics?

Tropical grasslands with widely scattered trees; warm temperatures; moderate to low precipitation; long growing season; moderate species richness and productivity.

What is vertical zonation?

Biomes change with elevation in a manner similar to changes with latitude because temperature decreases with elevation.

What defines marine biomes?

Defined by ocean currents and patterns of primary productivity in the oceans.

How many terrestrial ecosystems does WWF recognize?

867.

What is taxonomy?

Science of naming and classifying organisms according to standardized rules.

What is systematics?

Science of reconstructing evolutionary relationships among taxa.

List the major ranks in the Linnaean classification (from highest to lowest).

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

What are the three domains?

Bacteria, Archaea, and Eukarya.

Describe the number of described Animalia species.

About 1,200,000 described species.

Describe the number of described Plantae species.

About 290,000 described species.

Describe the number of described Fungi species.

About 80,000 described species.

Describe the number of described Protista species.

About 80,000 described species.

Describe the number of described Bacteria species.

About 5,000 described species.

Describe the number of described Archaea species.

About 300 described species.

What is the estimated range of total animal species?

About 2 million to 11 million predicted species.

Where is evolutionary uniqueness disproportionately concentrated?

In poorly known (mostly microscopic) taxa.

Biodiversity

The variety of life in all forms, levels, and combinations, including diversity within communities and across ecosystems.

Community

All of the individuals of all species in a given place at a given time; a collection of populations; the biotic component of an ecosystem.

Species diversity

Variation within or among communities described by richness, evenness, and distinctiveness.

Species richness

Number of species.

Evenness

Weighting by importance; how evenly individuals are distributed among species (often related to abundance, size, productivity).

Distinctiveness (similarity)

The distinctiveness of species composition, i.e., how unique or similar the species list is across communities.

Ecosystem

A system formed by the interactions of a community of organisms with their physical environment.

Biosphere

The zone of life on Earth; the sum of all ecosystems.

Biogeographic region

A geographic region defined by a unique assemblage of organisms.

Nearctic region

Temperate zones of the northern hemisphere in the New World (North America, Greenland, northern Central America); excludes southern Florida.

Neotropical region

Tropical zones of South America, southern Central America, and the Caribbean; includes the temperate zone of South America.

Palearctic region

Temperate zones of the northern hemisphere in the Old World (Europe and northern Asia); includes northern Africa; sometimes lumped with Nearctic as Holarctic.

Afrotropic region

Tropical and temperate zones of Sub-Saharan Africa; includes Madagascar and parts of the Arabian Peninsula and SW Asia.

Indo-Malaya region

Tropical and subtropical zones of the Indian subcontinent and Southeast Asia.

Australasia region

Australia, New Zealand, and New Guinea; contact with Indo-Malaya along Wallace Line.

Wallace Line

Boundary described by Alfred Russel Wallace between Borneo and Sulawesi, and through the Lombok Strait between Bali and Lombok (about 22 miles apart) separating Asian and Australian faunas.

Holarctic region

A proposed combined biogeographic region that merges Nearctic and Palearctic regions.

Biome

A major ecological unit defined by climate and dominant vegetation (e.g., forests, deserts, grasslands, tundra).

Tropical and subtropical moist broad-leaved forests

A biome with lush, broad-leaved trees in warm, wet conditions.

Deserts and xeric shrublands

Biomes characterized by very low precipitation and adaptations to dry conditions.

Boreal forests (taiga)

Coniferous forest biome in northern latitudes with cold climates.

Tropical and subtropical grasslands, savannas and shrublands

Biomes with grasses and scattered trees in warm regions with seasonal rainfall.

Biodiversity

The sum of all living organisms on Earth; can be considered at multiple levels (genetic, population/species, community, and ecosystem diversity).

Levels of biodiversity

The hierarchical levels at which biodiversity is measured: genetic, population and species, community, and ecosystem diversity.

Genetic diversity

Genetic variation within a species; the ultimate source of biodiversity; genes may exist in two or more alleles.

Allele

Alternate forms of a gene.

Evolution

Change in heritable variation through natural selection; adaptation to changing environmental conditions.

Population and species diversity

Diversity at the species level and within populations; a species may have multiple populations, some locally adapted with unique genetic diversity.

Community diversity

Diversity of species within a community.

Ecosystem diversity

Diversity of ecosystems within a region or on Earth.

Biosphere

The global sum of all living organisms and their environments.

Biogeographic regions

Regions defined by the geographic distribution of species.

Biomes

Large ecological zones with characteristic climates and communities.

Ecosystems

Dynamic networks of living organisms and their physical environment interacting as a system.

Communities

Assemblages of populations of different species interacting within an environment.

Population

All individuals of a given species in a specific place at a specific time.

Genes

Basic units of heredity; DNA sequences that determine inherited traits.

Species

Group of actually or potentially interbreeding organisms reproductively isolated from other such groups.

Endangered Species Act (ESA)

U.S. legislation providing protection to endangered species.

CITES

Convention on International Trade in Endangered Species; international agreement regulating trade in endangered species.

Biological species concept (BSC)

A group of actually or potentially interbreeding individuals reproductively isolated from other groups; inadequate for asexual or fossil forms.

Phylogenetic species concept (PSC)

A group of individuals sharing a common evolutionary history and diagnosable by a unique combination of characters.

Morphospecies

A group recognized by appearance (morphology); often used when ecological or phylogenetic knowledge is limited; also known as operational taxonomic units (OTUs).

Binomial nomenclature

Linnaeus’s system of two-part Latin names: genus and specific epithet; italicized; genus capitalized; example Homo sapiens.