Unit 3: Biodiversity & Conservation Flashcards
natural selection
those more adapted thrive and reproduce while others don’t live long enough to have off spring
speciation
the formation of a new species when populations of a species become isolated and evolve differently
What physical barriers can cause speciation?
mountains ranges or ocean
What factors aside from physical barriers (ex: mountain ranges and ocean) isolate a species, leading to speciation?
their mating seasons are not synchronized or their flowers mature at different times
What do land bridges allow for?
allow species to invade new areas
How are land bridges temporarily formed?
the lowering of sea levels, ice age
What is an example of a land bridge that has formed between North and South America?
Central America (North and South America were separated for a long time)
plate tectonics
the study of the movement of the plates
What effect does continental drift have on biodiversity?
Biodiversity increases because the number of degree of separation of habitats increases, promoting speciation, and species arrive or evolve
What is a result of the creation of mountain ranges, etc. through plate tectonics?
new habitats/niches
r
biotic potential/how fast a species can reproduce
What are the three types of biodiversity?
species, genetic, habitat
keystone species
a species that contributes greatly to an ecosystem even though they may not dominate in numbers
indicator species
serves as an early warning that an ecosystem is declining
foundation species
plays a major role in shaping communities by creating land enhancing habitats in ways that benefit other species
What is an example of a foundation species?
elephants (push over/uproot trees which creates opportunities for growth of grasses which benefits grazing species)
What is an example of a keystone species?
birds (seed dispersal/pollination)
K
carrying capacity
What is species diversity based on?
species richness and species evenness
species richness
variety/number of species
species evenness
abundance/number of organisms within a species
genetic diversity
the range of genetic material present in a gene pool or population of a species
habitat diversity
the range of different habitats in a particular ecosystem/biome
Where would habitat diversity be high?
the tropics, tropical rainforests
Where would habitat diversity be low?
near the poles, tundra
What are three advantages of high biodiversity?
- a complex system tends to be more resilient and stable
- higher genetic diversity leads to resistance to disease
- nutrient cycling is increased by deep rooted plants (deep roots bring nutrients to the surface, making them available to other plants)
What are three cases in which high biodiversity does not equate to having a healthy ecosystem?
- diversity could be the result of habitat fragmentation/degradation (species richness due to pioneer species invading bare area after a human disturbance)
- different plant species make managing grazing difficult (sheep and goats are selective in the grass species they consume)
- some stable communities rely on few producers (ex: grasslands)
When comparing two similar ecosystems/communities, what could low biodiversity indicate?
pollution, eutrophication, recent colonization of a site
eutrophication
a natural process that results from the accumulation of nutrients in lakes or other bodies of water, which leads to the excessive development of certain types of algae
Why is it important to repeat investigations of diversity in the same community or ecosystem?
to know if change is a natural process due to succession or due to impact of human activity (increase/decrease in biodiversity would tell us if conversation efforts are successful or not)
hotspot
region with a high level of biodiversity (have an unusually high number of endemic species) that is under threat from human activities
endemic species
those only found in that place
How many hotspots are there in the world?
about 30
How many tropical rainforest hotspots are there?
about 10
Where do hotspots tend to be?
near the tropics (there are fewer limiting factors in lower latitudes)
How much land surface do hotspots cover?
2.3%
At least how many endemic plant species do hotspots contain?
1,500 (Atlantic forest in Brazil contains about 8,000 endemic plant species, Coastal forests of Eastern Africa contain about 1,750)
What do hotspots tend to have nearby?
large human populations
What are three reasons critics say hotspots are misleading?
- focus on vascular plants and ignore animals (don’t represent species diversity/richness)
- do not consider genetic diversity
- do not consider value of services (ex: water resources)
How many plates are there world wide?
9 major plates and 15 minor plates (numbers fluctuate, so some might say 10 major plates and a variety of minor plates)
What are the three causes of plate motion?
- convection in the mantle (heat driven)
- ridge push (gravitational force at the spreading ridges)
- slab pull (gravitational force in subduction zones)
convection currents
hot material rises, cool dense material sinks
Pangaea
the landmass that existed when all 7 continents were once connected
What causes thermal convection?
uneven distribution of heat within the Earth
What is the main driving force for plate movement?
convection in the mantle
divergent boundaries
two plates move apart
What are divergent boundaries also called?
spreading centers
convergent boundaries
two plates move together
transform fault boundaries
two plates grind past each other (without the production or destruction of the lithosphere)
What do divergent boundaries create?
rift valleys (land/ocean) and mid-ocean ridges (ocean)
seafloor spreading
a process in which new seafloor (oceanic lithosphere) is formed through the spreading of ocean ridges to make room for rocks that are being forced up from inside the planet
Mid Atlantic Ridge
a mountain range running 10,000 miles across the ocean floor
oceanic ridge
continuous elevated zones on the ocean floor (rifts at the crest of ridges represent divergent boundaries) where seafloor spreading takes place
rift valleys
lowland regions that form at divergent boundaries
magma
molten rock that escapes from the mantle
What is the average spreading rate of divergent boundaries?
5 cm per year
What do convergent boundaries create?
volcanoes, trenches, island arcs, mountains
What happens to the oceanic plate when an oceanic plate and a continental plate converge?
The denser, oceanic slab sinks into the asthenosphere
What do oceanic and continental convergent boundaries create?
continental volcanic arcs, trenches
continental volcanic arcs
form in part by volcanic activity caused by the subduction of oceanic lithosphere beneath the continent
volcanic island arcs
form as volcanoes emerge from the sea
What happens when two oceanic plates converge?
the one that is more dense descends beneath the other
What do oceanic and oceanic convergent boundaries create?
volcanoes on the ocean floor, trenches
subduction zone
a collision between two of Earth’s plates, where one oceanic plate is forced down into the mantle beneath the second plate
What do continental and continental convergent boundaries create?
mountain ranges
How are trenches formed?
formed when one tectonic plate slides beneath another
What do movements along transform boundaries cause?
earthquakes
What do most transform fault boundaries connect (ocean-ocean plate boundaries)?
segments of mid-ocean ridges
lithosphere
comprise of plates, consisting of the crust and upper mantle
Ring of Fire
a massive chain of volcanoes along the Pacific Ocean
What four factors help maintain biodiversity?
- complexity of the ecosystem
- stage of succession
- limiting factors
- inertia/persistence
resilience
ability of an ecosystem to come back
inertia/persistence
ability of ecosystem to survive
Why is a system more resilient if it is more complex?
a system is more resilient if it is more complex because if one type of prey/food source/predator is lost, other species can fill the gaps left
Why are communities in the early stages of succession more vulnerable?
species diversity increases until a climax community is reached when the species composition is stable, so communities undergoing succession are more vulnerable than older ones which are more resilient/stable
What is an example of a persistent biome?
rainforest (hard to destroy because there are so many species, but if it does die it is too complex to recover, so the rainforest is not resilient)
What is an example of a resilient biome?
grassland (one species so that species could get sick and die easily so the grassland is not persistent, but it can easily come back so it is resilient)
What 6 factors lead to a loss of biodiversity?
- natural hazards
- habitat fragmentation
- pollution
- invasive species
- spread of disease
- agricultural practices
What do natural hazards lead to?
loss of habitat
How do humans cause similar problems to natural hazards?
humans kill animal/destroy habitats
habitat fragmentation
when parts of a habitat are destroyed, leaving behind smaller unconnected areas that behave like islands
What are the fragmented habitats typically divided by?
roads, power lines, fences, etc.
What causes pollution?
human activity
Why have humans historically attempted to introduce non-native species?
pest control
What is an example of a non-native species that led to positive effects?
potatoes from Europe to America
What is an example of a non-native species that has led to negative effects?
cane toads
How does disease spread in more concentrated populations?
diseases spreads faster
How do humans purposefully reduce biodiversity?
agricultural practices
monoculture
the cultivation of a single crop in a given area
What percent of the animals that have ever lived now extinct?
over 99%
How many years ago was the Ordovician extinction?
440 million years ago
What was the Ordovician extinction?
volcanic rock that was worn down by water/wind reacted with and absorbed CO2, decreasing the amount of CO2 in the atmosphere, causing temperatures to drop; water was then locked away as ice, causing ocean levels to drop and shallow seas to drain
What percent of species was lost as a result of the Ordovician extinction?
86%
How many years ago was the Devonian extinction?
364 million years ago
What was the Devonian extinction?
the land was colonized by plants and these plants absorbed enough CO2 to create another round of global cooling, changing soil, causing nutrients to wash into the ocean, creating enormous amounts of algae; the algae sucked up oxygen, choking about 50% of the marine population to death
How many years ago was the Permian extinction?
251 million years ago
What was the Permian extinction?
billions of tonnes of volcanic gases destroyed the ozone layer, increasing ocean temperatures and causing acid rain to fall all over the planet
What percent of species was lost as a result of the Permian extinction?
70% land species, 95% ocean species
What was the Triassic extinction?
a volcanic rift opened in the middle of the planet, splitting America and Europe/Africa, creating the Atlantic Ocean; the volcanoes in the volcanic rift spewed out CO2, increasing temperatures around the planet
What percent of species was lost as a result of the Triassic extinction?
80%
How many years ago was the Triassic extinction?
200 million years ago
How many years ago was the Cretaceous-Tertiary extinction?
65 million years ago
What was the Cretaceous-Tertiary extinction?
an asteroid crashed into the Earth and the impact shot million of tonnes of dust into the atmosphere, blocking sunlight, and spelling an end to all large dinosaurs
What is the Holocene extinction?
caused by humans; CO2 levels are rising (climate change), and humans have exterminated hundreds of species by hunting, fishing, habitat destruction, and pollution
How many mass extinctions have occurred?
5, but scientists believe we are in the middle of a 6th
How many species are there estimated to be?
7 million
How many of the estimated 7 million species have been described or named?
1.4-1.8 million
What percent of identified species are in the tropics?
66%
What percent of tropical forests have been cleared by humans?
50%
What are the three general patterns of population distribution?
clumping, uniform distribution, random distribution
clumping
population is distributed in clusters
uniform distribution
population is evenly spaced
random distribution
population is randomly spaced
What are four reasons populations live in “clumps”?
- resources vary greatly from one place to the next
- living in groups provides protection
- living in packs gives predators a better chance
- some species form temporary groups while raising offspring
allelopathy
the release by a plant of a toxin to suppress growth of nearby competing plants, often resulting in uniform distribution
What is an example of random distribution?
the seeds of a plant blow in the wind and grow where they land
locally extinct
a species is no longer found in an area it once inhabited but it is still found somewhere else in the world
ecologically extinct
when so few members of a species are left that the species no longer plays its ecological role
globally/biologically extinct
a species is no longer found on the Earth
What is an example of an organism that is globally/biologically extinct?
mammoth, dodo, saber tooth tiger, passenger pigeon
background extinction rate
the natural extinction rate of all species
What has been the cause of most mass extinctions?
rapid change in climate caused by a natural disaster
mass extinction
spike in extinction rate
How many times larger is the background extinction rate today than “usual”?
100 times larger
What is the background extinction rate based on?
fossil record
Where is the background extinction rate greater?
hotspots
What are four ways humans cause ecosystem stress?
- transform the environment
- overexploit resources/species
- introduce alien/invasive species
- pollute the environment
weedy species
species that do well in the environments that we create
What percent of plants/animals have gone extinct between 1905-2015?
25%
endangered
likely to go extinct in the near future
flagship species
a species selected to act as an ambassador, icon, or symbol for a defined habitat, issue, campaign, or environmental cause (ex: panda)
What factors make a species prone to extinction?
- narrow geographical range
- small population size/low genetic diversity
- low population density (production)
- few populations of the species
- a large body (per organism within a species)
- low reproductive potential
- seasonal migrants
- poor dispersers
- specialized feeders/niche requirements (specialists)
- edible to humans
- island organisms
How does narrow geographical range make a species prone to extinction?
if a species only lives in one specific habitat and that habitat is destroyed, the species often becomes geographically extinct
How does a small population size/low genetic diversity make a species prone to extinction?
a smaller population has a smaller genetic diversity and is less resilient to change, and cannot adapt well to change; a smaller population also suffers from interbreeding, resulting in the extinction of the remaining population
How does low population density make a species prone to extinction?
if an individual of a species requires a large territory/range, it becomes more difficult to find/breed with other individuals of the same species; habitat fragmentation often makes this worse
How does having few populations of a species make the species prone to extinction?
if there are only one or two populations left of a species, then that is there only chance of survival
How does having a large body (organism) make a species prone to extinction?
only 10% of energy is passed on to the next trophic level and 90% is lost to the environment, so large top predators are rare; these species also compete with humans for food, may be a danger to humans, and a re hunted for sport
How does having a low (r) reproductive potential make a species prone to extinction?
slow/infrequent reproduction means the population takes a long time to recover
How does migrating seasonally make a species prone to extinction?
migrating is dangerous/risky (habitat fragmentation makes migrating more challenging), the species requires 2 habitats to stay intact
How are species that are poor dispersers prone to extinction?
species that cannot easily move to new habitats are in trouble because climate change resulting in biome shift may mean the species dies out before it can move (ex: plants)
How are specialists prone to extinction?
specialists rely on constant conditions, change happens often
Why are island organisms particularly prone to extinction?
- populations tend to be small
- islands have a high degree of endemic species
- low genetic diversity
- islands tend to be vulnerable to the introduction of non-native species to which they have no defense mechanism
minimum viable population size
the population size needed for a species to survive in the wild
What factors influence extinction rates on an island?
size of island and distance from shore
What is considered the absolute minimum viable population size for large carnivores?
500
What five factors determine the minimum viable population size of a species?
- genetic diversity
- r
- mortality rate
- growth rate
- current threats
What are the 8 Red List factors for conservation status?
- numbers
2 distribution and geographic range - habitat fragmentation and quality of habitat
- degree of specialization
- reproductive potential
- behavior
- trophic level
- probability of extinction
What are the two approaches to conservation?
species-based approach, habitat-based approach
What are five examples of species-based conservation?
- CITES (the Conservation on International Trade in Endangered Species of Wild Fauna and Flora)
- Captive breeding and zoos
- Botanical gardens and seed banks
- Flagship species
- Keystone species
What is CITES?
an international agreement between governments to address the endangerment of species due to international trade
Why is it difficult to reintroduce a species into the wild after the species has been bred in captivity?
programs to reintroduce populations are expensive and few are successful, and if the program is not successful it can be seen as a waste of money, poorly run, or unethical
In what case is it impossible to reintroduce a species to its native habitat?
the habitat has been destroyed
In addition to growing plants, what is the purpose of botanical gardens?
identify, classify, carry out research, education, and conservation
Approximately how many botanical gardens are there around the world?
1500
What are seed banks?
where seeds are stored, frozen, and dry for many years
What are the disadvantages of flagship species?
they take priority over other species, if they become extinct the message is that we have failed, they may be in conflict with local peoples
Why are flagship species sometimes referred to as umbrella species?
conservationists use umbrella species to gain support and other species who share the species’s habitat are also protected under its “umbrella”
Where were many protected areas or nature reserves set up in the past?
early reserves simply put on unwanted or degraded land, which may not have been large enough or appropriate for the needs of the species they are aiming to protect
What is the focus of UNESCO’s Man and the Biosphere programme (MAB)?
to promote sustainability and conservation by creating 480 reserves in over 100 countries
What is a biosphere reserve?
a protected area for the conservation of wildlife, plant, and animal resources that satisfies human needs as well
What is an example of habitat-based conservation?
designing protected areas
What is the consensus of the SLOSS (single large or several small) debate?
large or small will depend on the size and requirements of the species that the reserve is there to protect
What are some advantages of several small (SS) reserves?
provide a greater range of habitats, more populations of rare species, danger of a natural disaster wiping out the reserve and its inhabitants is reduces as some reserves may escape the damage
What are some advantages of single large (SL) reserves?
minimizes edge effects, provides habitats for more species, contains sufficient numbers of a large wide-ranging species - top carnivores
ecotones
where two habitats meet and there is a change near the boundary
Where do edge effects occur?
ecotones
What are corridors?
strips of protected land that link reserves
What do corridors allow for?
allow for seasonal migration and increase genetic diversity
What is a buffer zone?
the transitional zone around the core reserve
Do circular or long thin reserves have a larger edge effect?
long thin reserves
intrinsic value
value based on existence, regardless of usefulness to humans
instrumental value
ecological or economic service, human value
What are the two types of instrumental value?
use value and non-use value
What are examples of use value?
jobs, food, medicines, pest control, nutrient recycling
What are example of non-use value?
satisfaction of knowing it exists, aesthetic value, bequest (protect for future generations)
What are 2 example of direct values found in biodiversity?
- food sources
- natural products
What are 9 examples of indirect values found in biodiversity?
- environmental services
- educational services
- biological control agents
- gene pools
- future potential use
- human health
- human rights
- ecotourism
- ethical/intrinsic value
conservation biology
sustainable use and management of resources
preservation biology
attempts to exclude human activity in areas were humans have not yet encroached
What is an IGO?
intergovernmental organization composed of and answering to a group of member states (countries), also called international organizations
What are two examples of IGOs?
the UN, IPCC
What is a GO?
governmental organization part of and funded by a national government, highly bureaucratic, mostly do research, regulation, monitoring, and control activities
What are two examples of GOs?
EPA, Environmental Protection Department of China
What is an NGO?
non-governmental organization that is not for profit, and can be run by international or local and funded by altruists and subscriptions
What are two examples of NGOs?
Friends of the Earth, Greenpeace
