Biodiversity Variety of the earth’s species, the genes they contain, the ecosystems in which they...
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Transcript of Biodiversity Variety of the earth’s species, the genes they contain, the ecosystems in which they...
BiodiversityVariety of the earth’s species, the genes they contain, the ecosystems in which they live, and the ecosystem processes such as energy flow and nutrient cycling that sustain all life.
Hot Spots A hotspot is an area where there are
many threatened and endangered species
There are currently 34 hotspots in the world today
Species Diversity Number and abundance of species
present in different communities
Ecological Diversity The variety of terrestrial and aquatic
ecosystems found in an area or on the earth
Functional Diversity The biological and chemical processes
such as energy flow and matter recycling needed for the survival of species, communities and ecosystems Food Chains & webs
Genetic Diversity The variety of genetic material within a
species or a population
Theory of Natural Selection Explains how life has evolved from a
common ancestor
Survival of the fittest Organisms suited for the environment
will survive to reproduce, thus passing down desirable traits. Examples:
Giraffes Camels Influenza virus Venus fly trap
NOTE – fittest does not equal strongest!!!
Natural Selection and Geological Processes Location on the earth influences
biodiversity (rainforest vs. tundra) Continental movement
Earthquakes and volcanoes Climate change
Cyclic cooling and heating of the earth Catastrophic events
Asteroid impacts, major volcanic eruptions
Continental movement Theory of Continental Drift The earth has large plates located
between the lithosphere and asthenosphere
These plates move very slowly (1-3cm/yr)
This creates oceans, mountain ranges, volcanoes, earthquakes, trenches
225 million years ago
Fig. 4-5, p. 88
135 million years ago
Present65 million years ago
225 million years ago
Continental Movement
Climate Change
Climate Change and Natural Selection
Changes in climate throughout the earth’s history have shifted where plants and animals can live.
Figure 4-6
Catastrophic events Asteroid impacts Super Volcanoes
These affect biodiversity locally and on a world-wide scale
Speciation - formation of a new species Two Phases
1. Geographic isolation A population is removed from others of it’s
species for a long period of time 2. Reproductive isolation
The removed population becomes so genetically different over time that it can no longer interbreed with others of it’s species
Measurements of Biodiversity Species diversity – the number of
different species in a community
Species evenness – the abundance of species in a community
Richness and Sustainability Higher species richness = higher
productivity = higher sustainability
Reasons: More likely to withstand droughts, disease,
climate change, nutrient shortages Higher number of producers lead to a
higher biomass which leads to more carbon and nitrogen cycling
Extinction – the loss of a species Background extinction – low rate of
extinctions
Mass extinction-high rate of extinctions due to specific cause Climate change
Three types of extinctions Local: A species is no longer found in an
area it once inhabited but is still found elsewhere in the world.
Ecological: Occurs when so few members of a species are left they no longer play its ecological role.
Global (biological): Species is no longer found on the earth.
Global Extinction
Some animals have become prematurely extinct because of human activities.
Figure 11-2
Steps to extinctionBackground extinctions:
1. Rare2. Threatened3. Endangered4. Extinct
Endangered and Threatened Species: Ecological Smoke Alarms
Endangered species: so few individual survivors that it could soon become extinct.
Threatened species: still abundant in its natural range but is likely to become endangered in the near future.
Figure 11-3
Red lists ICUN – International Union for the
Conservation of Nature and Natural Resources
Published list of threatened species www. iucnredlist.org
Some species are more prone to extinction: K-strategists Specialists Tertiary consumers Fixed migratory patterns Narrow distribution Commercially valuable Large territories
Fig. 11-3, p. 224
Grizzly bear Kirkland’s warbler
Knowlton cactus
Florida manatee
African elephant
Utah prairie dog Swallowtail butterfly
Humpback chub
Golden lion tamarin
Siberian tiger
Fig. 11-3, p. 224
Hawksbill sea turtle
Giant panda Black-footed ferret
Whooping crane
Northern spotted owl
Blue whale
Mountain gorilla Florida panther
California condor
Black rhinoceros
Fig. 11-8a, p. 230
Range 100 years ago
Indian Tiger
Range today(about 2,300 left)
Fig. 11-8b, p. 230
Range in 1700
Black Rhino
Range today(about 3,600 left)
Fig. 11-8c, p. 230
Probable range 1600
African Elephant
Range today
Fig. 11-8d, p. 230
Range today(34,000–54,000 left)
Asian or Indian Elephant
Former range
Extinction Rate The percentage of species that go
extinct within a certain time period
The current extinction rate is increasing at an alarming rate due to human activities
History of Extinctions
Extinctions have existed long before humans had an influence
The current extinction crisis is the first to be caused by a single species- US!
. This is happening faster than ever; a few decades versus thousands to millions of years.
Humans are eliminating not only the species but, the environment. Ex. Tropical rainforest
Endangered Species
Effects of Humans on Biodiversity
The scientific consensus is that human activities are decreasing the earth’s biodiversity.
Figure 4-13
Human Caused ExtinctionCauses include:
HIPPO C Habitat Destruction Invasive species Population Growth Pollution Over-harvesting Climate Change
Fig. 4-12, p. 93
Tertiary
Bar width represents relative number of living speciesEra Period
Species and families experiencing
mass extinction
Millions ofyears ago
Ordovician: 50% of animal families, including many trilobites.
Devonian: 30% of animal families, including agnathan and placoderm fishes and many trilobites.
500
345
Cambrian
Ordovician
Silurian
Devonian
Extinction
Extinction
Pal
eozo
icM
eso
zoic
Cen
ozo
ic
Triassic: 35% of animal families, including many reptiles and marine mollusks.
Permian: 90% of animal families, including over 95% of marine species; many trees, amphibians, most bryozoans and brachiopods, all trilobites.Carboniferous
Permian
Current extinction crisis causedby human activities. Many speciesare expected to become extinctwithin the next 50–100 years.Cretaceous: up to 80% of ruling reptiles (dinosaurs); many marine species including manyforaminiferans and mollusks.
Extinction
Extinction
Triassic
Jurassic
Cretaceous
250
180
65Extinction
ExtinctionQuaternary Today
Natural Extinctions
Causes include Climate change Change in ecosystem Lack of adaptations to change
How do extinctions affect us? Use value lost – medicinal use,
recreation, crops, lumber Economic value – ecotourism (African
safari) Genetic information – genetic diversity
lost Non-use values – appreciation
Case Study: The Whooping Crane
Habitat loss and unregulated hunted led to a severe decrease in the species
In 1941 there were an estimated 14 whooping cranes left in the wild
The decline in this species was a major factor leading up to the creation of the Endangered Species Act
Saving the Whooping Crane
Ex-situ conservation: Conservation outside of the natural habitat
In-situ conservation: Conservation in the natural habitat
A combination of techniques was used to save the Whooping Crane
Teaching migration
The Endangered Species Act Established in 1973 Overseen by the US Fish and Wildlife
Service Penalties of violating the act: http://
www.gc.noaa.gov/schedules/6-ESA/EnadangeredSpeciesAct.pdf
Funded by US taxes and penalty money
The Act: authorizes the determination and listing of species as
endangered and threatened; prohibits unauthorized taking, possession, sale, and
transport of endangered species; provides authority to acquire land for the conservation
of listed species, using land and water conservation funds;
authorizes establishment of cooperative agreements and grants-in-aid to States that establish and maintain active and adequate programs for endangered and threatened wildlife and plants;
authorizes the assessment of civil and criminal penalties for violating the Act or regulations; and
authorizes the payment of rewards to anyone furnishing information leading to arrest and conviction for any violation of the Act or any regulation issued thereunder.
Case Study: The U.S. Endangered Species Act
Biodiversity hotspots in relation to the largest concentrations of rare and potentially endangered species in the U.S.
Figure 11-18
CITES Convention for the International Trade of
Endangered Species - CITES Is a voluntary agreement among
participating countries to stop the trade of listed species
180 countries participate: 5,600 animal species and 30,000
animals are protected under this act
Deforesting the Rainforest The rainforest provides half of the
world’s hardwood 80% of the Rainforest’s nutrients are in
the top, organic layer(O-layer) After a Rainforest has been clear cut, it
will not re-grow Usually, deforested rainforests are
replaced with grassland
Neem Tree Provides:
Fuelwood & Lumber Infection-fighting cabability Birth control – seeds contain a strong
spermicide
Fragmentation Habitat fragmentation is when an
ecosystem is divided by a highway, neighborhood, buildings or other structures/land uses.
Leads to: Decreased genetic diversity Loss of habitat Loss of breeding grounds May disrupt migration patterns Disruption of food chains
The major decline in the worldwide catch of fish since 1990 is because of over-fishing.
By-catch- fish or animals that were not meant to be caught.
Fishing Problems & Techniques
About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits. Big fish are becoming scarce. Smaller fish are next. We throw away 30% of the fish we catch. We needlessly kill sea mammals and birds.
Overfishing and Extinction: Gone Fishing, Fish Gone
Fig. 12-A, p. 255
Fish farming in cage
Trawler fishing
Spotter airplane
Sonar
Trawl flap
Trawl lines
Purse-seine fishing
Trawl bagFish school
Drift-net fishingLong line fishing
Lines with hooks
Fish caught by gills
Deep sea aquaculture cage
Float Buoy
Trawler FishingCatches shrimp, shellfish, flounder
and other anials that live on the ocean floor
Drags a funnel shaped net along the ocean floor, weighted down with chains or metal plates
Some nets are large enough to hold 12 jumbo jets!!
Purse Seines
A large purse-like net is put into the ocean and is then closed like a drawstring purse to trap the fish.
Tuna is a fish typically caught in purse seines
Dolphins are a by-catch of purse seines
Purse Seines
Lines are put out that can be up to 80 miles long w/ thousands of baited hooks on them. These are left out free-floating for days and then the boat comes back and picks them up.
Pilot whales, dolphins, sea turtles, and birds are by-catch of this technique.
Deadliest Catch
Long-line fishing
Each net hangs as much as 50 feet below the surface and up to 34 miles long.
Anything that comes into contact w/ these nearly invisible nets are entangled.
This leads to overfishing Many unwanted fish and marine mammals, turtles and
seabirds are caught.
Drift-net fishing
Regulations on Fishing Marine and mammal protection act -
provides for protection and conservation of marine mammals
Magnuson Act- Sets quotas, size limits and seasons for fishing
UN Law of the Seas – allows countries to establish fishing quotas
Marine Sanctuaries Act- provides protected habitat for marine organisms