BIO 480 Conservation Biology Exam 1

extinction

complete loss of an entire species, global loss, extension of natural selection

extirpation

regional loss of a species from a community

speciation

adding additional species via evolution, opposite of extinction

at what rate should extinctions occur

extinctions should occur at roughly the same rate new species evolve

do famous evolutionary biologists emphasize biological or physical factors as the driving force of extinction

biological

is extinction inevitable by evolution

to some degree yes, over 99% of species known to science are now extinct, occurs slowly-background extinction rate

what can elevated rates of extinction lead to

when extinction rates greatly exceed background rate this can lead to mass extinction events

mass extinction

75% of species lost in short geologic time-2 million years

how many mass extinctions have we had since the Cambrian period

5

end ordovician mass extinction event

rapid cooling due to first terrestrial plants, mountain range formations, and positioning of land masses; glaciation causes sea levels to fall, takes 5 million years for diversity to recover

late devonian extinction

age of fishes, first land tetrapods, rapid expansion of land plant diversity, results in weathering of rocks, causes cooling and anoxic conditions in water

end permian extinction

the great dying, volcanic eruptions in areas with a lot of carbon deposits, rapid warming and ocean acidification ensued, major collapse of corals and marine communities, 8-10 million years to recover

end triassic extinction

smallest, volcanoes, warming, and anoxic ocean conditions

end cretaceous (K/Pg or K-T)

66 mya, asteroid, sediment blocked sun for months, differs from others because they were mostly marine events

current extinction event

extinction rate is elevated past background rate, experts say we are at the beginning of the 6th mass extinction, evidence says it is tied to humans

how old is earth

4.5 billion years

when did the first vertebrates appear

500 mya

when do modern humans appear in the fossil record

200,000 years ago

what kept populations low of early humans

hunter-gather lifestyle, increased with agriculture, rapid growth from industrial revolution in the 18th century-reached 1 billion

how do prehistoric homo sapiens tell us how humans have impacted biodiversity

areas colonized by prehistoric homo sapiens had high extinction events

early humans and extinction in north america

previously home to many megafauna, 74-86% became extinct after humans arrived due to hunting and burning/clearing of forests; similar pattern of decline 40,000 years ago in australia where a variety of large animals disappeared when humans arrived, islands like madagascar; africa is one of the few places where megafauna are still abundant, african species had been coevolving with humans

coevolution

changes that occur between organisms as a response to interactions between them and the resulting mutual selective pressures that those interactions cause

when has the majority of habitat loss occurred

last 100-200 years

recent extinctions

early human caused mass extinctions are known only from fossil evidence, written records date back to 1600s, primarily large species with a focus on birds and mammals, they are well documented so they provide insight into extinction crisis

centinelan extinction

extinction of a species not yet described by science

mammal background extinction rate

2 extinctions per 100 years per 10,000 species, 9 since 1900, but actually 477 have gone extinct

what two factors can provide earlier indications of an extinction

extirpation and range constrictions

there is hope because…

most modern species are still represented somewhere on the planet, there are opportunities for conservation and restoration, human population growth is slowing especially for industrialized nations, shift from geometric to logistic growth

how do spiritual practices practice conservation

confucianism, taoism, hinduism, and buddhism all emphasize natural areas as spiritual places or living entities, islam, judaism, and christianity have sacred responsibility to guard nature

early management practices to protect shared resources

hunter-gather societies had systems-eldest male sets fishing limits in tribes; intergenerational sustainability-chinese philosophy

nature reserves and nobility

forests were reserved for kings and hunting, later used for lumber for kingdom, real nature reserves without the purpose of religion or hunting are relatively new-last 4 centuries

which nation had the first national park

mongolia in 1783

US was first to develop a national parks system

the first one was yellowstone, approved on march 1, 1872

what were john muir’s ideas

the goal of conservation is to preserve wilderness areas that are unoccupied and untouched by human beings

what were gifford pinchot’s ideas

natural resources should be used in ways that are sustainable

what were leopold’s ideas

humans have an ethical obligation to manage nature in ways that maintain the health of the ecosystem

when did conservation biology form and what year was the foundational paper

1980 and 1985

conservation biology

integrated, multidisciplinary scientific field that developed in response to the challenge of preserving species and ecosystems.

3 goals:

document full range of biodiversity on earth; investigate human impact on species, genetic variation, and ecosystems; develop practical approaches to prevent the extinction of species, maintain genetic diversity within species, and protect and restore biological communities and their associated ecosystem functions

three main levels of biodiversity

genetic diversity, species diversity, community/ecosystem diversity

genetic diversity

variation within members of the same species, ultimate source of biodiversity, genetic differences are crucial for evolution, genetically homogenous populations lack variation that is good to survive adverse events

genetic bottlenecks-significant reduction in population size, leading to loss in genetic diversity-cheetahs: 100,000 and 10,000 YA, recovered to 100,000 in 1800s but now 7,000, 0.1-4% of genetic variation

population

group of individuals that occupy a particular geographic area and can interbreed

2 ways to measure genetic diversity

allelic diversity: variety of alleles found at a particular gene within a population or species, allele frequency/polymorphism(P)-fraction of gene in which alternative alleles occur; influenced by natural selection, genetic drift, and gene flow, represents long-term adaptive potential and very sensitive to bottlenecks, traits can be lost quickly

heterozygosity(H)-variety of genes found on chromosome where the individual is heterozygous; influenced by inbreeding and outbreeding; less sensitive in short term to bottlenecks

H and P are complimentary, healthy levels can help ensure the reproductive success, growth, and adaptability of rare or threatened species

species diversity

species that comprise a biological community; most widely used measure of biodiversity because species is the most fundamental unit of evolution

community: collection of species that occupy and interact in a location

3 main definitions of species

biological species concept, morphological species concept, evolutionary species concept

biological species concept

individuals that can interbreed with each other and do not breed with other species

challenges: asexual species, physical/geographic barriers, hybridization

morphological species concept

individuals that are morphologically, physiologically, or biochemically distinct from other groups in characteristics

challenges: members of the same species can have high phenotypic variation in the same population, can vary in consistent ways, range-specific variation can be misleading

cryptic species appear visually indistinguishable but are evolutionarily distinct enough to be considered distinct species

evolutionary species concept

a species is a group that share similarities of DNA, evolutionary past indicates a species; historically difficult due to limited genetic technology, very feasible to look at genetic sequence of different taxa at lower costs

cryptic speciation and conservation

if two or more species are mistaken for one, the population and distribution of that species can be inflates which can lead to more restricted ranges increasing the risk of extinction due to lack of monitoring

species richness

number of unique species

simpson’s dominance index (D)

probability that two species from the same community are the same species, 0-1, closer to 1 means strong dominance and low diversity, diversity index is 1-D

shannon’s diversity (H)

combines evenness and richness, more weight to rare species and emphasizes species richness

ecosystem

biological community and abiotic environment

common aspects of community structure

trophic structure, food webs/species interactions, composition of impactful species

trophic structure

trophic cascades, way to think about community structure

food webs/species interactions

provide better representations of trophic interactions, network analysis can identify important species and dependencies that exist within a web, loss of one species can result in a secondary extinction, multiple secondary extinctions = extinction cascade

species composition

some species have impacts in an ecosystem that are disproportionate to their abundance

ecosystem engineers influence the diversity of a community by creating a habitat for other species, keystone species influence the diversity of a community through species interaction

ecosystem engineers

beaver dams create wetlands that support biodiversity and help reduce flood impacts, went extinct in the UK but are now returning and studies suggest their power to restore damaged ecosystems, 12 years after reintroduction a degraded wetland saw 50% more plant diversity and major wildlife gains

biodiversity

earth has higher biodiversity now despite losses in recent years

are we more likely to discover new phyla or a new genera

genera

8 biogeographic realms

palearctic, afrotropical, indo-malay, australasian, oceanic, nearctic, neotropic, and antarctic

biomes

areas that can be identified by their dominant vegetation type or by their dominant physical processes in aquatic habitats; terrestrial biomes change as a function of temperature and rainfall; tropical forests, coral reefs, and freshwater areas are most diverse

biodiversity hotspots

high levels of species richness, 25

4 types of ecosystem services

supporting, provisioning, regulating, cultural

supporting services/ecosystem functions

control the stocks and fluxes of energy and matter in ecosystems, influenced by organisms that becomes involved in fluxes, resource capture, biomass production, decomposition and nutrient cycling to be broken down into soluble inorganic forms

provisioning services

material outputs from ecosystem that are used by people; food, medicine, raw materials, biotech

regulating services

regulate stability of ecosystem processes over time; affect water, soil, plants, climate, protection from natural disasters, etc.; natural insurance for human well-being

cultural services

nonmaterial benefits people obtain from ecosystems; powerful motivator; ecotourism

biological characteristics most important for regulating ecosystem services

functional traits of organisms, biodiversity levels

functional traits

morphological, physiological, and behavioral traits of species will dictate ecological role species will play, ES are often product of small number of species, usually dominant, changes in density or biomass of that dominant species can be used to predict the impact on the ecosystem function, scientists are building functional trait databases to link species traits to ecosystem services and how they respond to environmental change

animal examples: body size, diet, locomotion, etc.

plant examples: leaf area, root depth, wood density, nitrogen content, etc.

biodiversity

strong evidence that genetic diversity and species diversity regulate supporting services, species richness increases capture, higher net primary production, also increases ecosystem stability so higher diversity resulted in less yearly fluctuation of biomass

crops with more genetic diversity have higher yields, oceans with more fish species have more stable fisheries yields, forests with more tree species have more wood, ecosystems with more plant species are more resistant to invasive pests and disease, ecosystems with more plant species sequester more carbon and lead to more fertile soils

4 possible mechanisms: niche partitioning, positive interactions, selection effect, dilution effect

niche partitioning

`dividing limited resources can lead to improved efficiency

positive interactions

positive interactions between species can allow communities to be more efficient and productive

selection effect

with a lot of species, at least one will be productive/good for a particular service

dilution effect

more species reduces risk of infection by zoonotic diseases because they are likely to meet more incompetent hosts