biodiversity 60 slides
TRANSCRIPT
What is biodiversity and how is it measured?
• What is Biodiversity?– The variation that exists in the natural
world at all levels of biological organization– All organisms in a defined area, all of their
variations and all of their interactions with each other and with the physical environment
Levels of Biodiversity
1. Genetic diversity: the gene pool within a population
2. Species diversity: the number and types of species in an area
3. Higher taxonomic diversity
4. Community Diversity
5. Ecosystem diversity (Habitat diversity)
Species diversity has two components:
1. Species richness: how many different species are present in a habitat
2. Relative abundance: total number of individuals of each species present
Species Richness and Abundance of a Swamp Forest on Maryland’s Eastern
Shore
4%
6%
8%
14%
17%
18%
33%
7. American Beech
6. Loblolly Pine
5. American Holly
4. Oaks
3. Sweet Gum
2. Black Gum
1. Red Maple
2003
Species diversity has two components:
1. Species richness: how many different species are present in a habitat
2. Relative abundance: total number of individuals of each species present
3. Which area is more diverse?
Defining Biodiversity:
• Old growth forest in the Shenandoah Mountains of Virginia – 50,000 trees represented by 10 species.
• Managed forest, recently clear cut– 45,000 trees are maple and birch– Only 1/10th of the forest is represented by
the remaining 8 species
Importance of TaxonomyNaming Species
1. Naming things upon which we depend for food and medicine means survival.
2. Important to measuring biodiversity
3. Conservation
Basics About TaxonomyKingdom
Phylum or Division
Class
Order
Family
Genus
Species
Most inclusive category
Least inclusive category
Linnaeus (1707 -1778)
Taxonomy
Linnea borealisTwin Flower
Binomial Nomenclature
Felis domesticus L.
Genus Species epithet Author
The house cat
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Felis
Species: Felis domesticusClassification & Taxonomy
“Wild”Felis sp.
Felis pardalisOcelot
BobcatLynx rufus
Panthera tigris
Panthera leo
Puma concolor
Other Genera of the Cat Family
Family:Felidae
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Genus: Felis
Species: Felis domesticusClassification & Taxonomy
Suborder: Aeluroidea
Order: Carnivora
Suborder: Arctoidea
Pinnipedia
Otariidae -- sea lions, eared seals, fur seals
Odobenidae -- walrus
Phocidae -- true (earless) seals, elephant seals
Canidae -- dogs, wolves, foxes, coyotes, dingos
Ursidae -- bears, panda
Procyonidae -- raccoons, kinkajous, ringtails, coatis
Mustelidae -- weasels, ferrets, skunks, badgers, otters, sea otter
Suborder: Aeluroidea
Viverridae -- mongooses, meercats, civets, linsangs
Hyaenidae -- hyenas, aardwolf
Felidae -- cats, lions, tigers, leopards, cheetah
FYI
Aeluroidea
Kingdom Animalia Animalia
Phylum Arthropoda Chordata
(Vertebrates)
Class Malacostraca Mammals
Order Decapoda Primates
Family PORTUNIDAE swimming crabs
Hominids
Genus Callinectes Homo
Species Callinectes sapidus
The Blue Crab
Homo sapiens
Eubacteria
Archaebacteria
Animal
Fungi
Plant
Protist
Commonancestor
Domains:
Kingdoms:
Eubacteria Archaea Eukarya
Domains and Kingdoms
Eubacteria &Archaebacteria
ProtistaAlgaeSlime moldsProtozoa
FungiTrue fungi
PlantsBryophytesVascular Plants
AnimalsMulticellularanimals
Absorb food in solution
photosynthesis
Ingest food
Food Requirements
chemosynthesisphotosynthesis
chemosynthesisphotosynthesisIngest food
Kingdom
What you need to know about Classification
• The order of classification
• Binomial nomenclature (genus, species)
• The three Domains
• The five Kingdoms
• The ecological role of each kingdom
• The scientific name of the Blue Crab
Rich in Species, Poor in Knowledge
E.O. Wilson estimated 1.75 million species are living on the planet. Scientists generally disagree with the exact number but, agree with Wilson that 1.4 M represents probably a mere 1/10th of the total diversity.
Why do we know so little?
Other estimates:4-112 million (7 million)
Number of Living
Species of All Kinds of
Organisms Currently
Known
Insects54%
Other Animals 20%
Bacteria 4%
Fungi 5%
Algae 2%
Plants 18%
Protozoa 2%
What do we know?• Estimates of the # of species
• More species are located in the tropical regions of the world– 2/3rd – 3/4th of all species live in tropical rain
forests which cover only 7% of the earth’s surface
Diversity of North and Central American birds
Why do we know so little?
1. Not all species have been discovered– #’s are biased toward animal species– Know more about species in developed Nations– Not all species are named as a result of unclear
species concepts in taxonomy
2. On-going extinction: species loss in tropical forest is estimated at 6000/year,
• Tropical rain forests are more species rich than northern regions of the world
• What are some factors that might account for this?
Some factors that affect the biodiversity of an area
1. Historical Events– Time
2. Habitat conditions
3. Habitat structure
4. Climate stability
5. Competition– Predators– Keystone species
6. Disturbance
1. Historical Events• Each part of the world
has a unique history• Effect of the recent
Ice Age in the northern hemisphere– Ireland has no snakes
• Time: Older Areas have more species than younger areas
Extent of Glaciation in the Pleistocene
2. Habitat Conditions
• Areas with extreme climate or conditions harbor fewer species
• Soldiers Delight Natural Environment Area (NEA) is comprised of 1,900 acres of serpentine barren. The area has over 39 rare, threatened, or endangered plant species as well as rare insects, rocks and minerals.
• Delaware River and Pollution
3. Habitat Structure• Terrain that is simple, uniform, and
without much physical variation tends to have fewer species than a complicated terrain with wet and dry spots
• Ecologists call these microhabitats• A piece of property with a patch of forest,
a small wetland, and a field with harbor a greater diversity than the same sized property that is covered with only forest.
3. Habitat Structure: The Forest Community
stratification
• The canopy
• The shrub layer
• The understory
• The herbaceous layer– most conspicuous in the spring
• The forest floor
4. Climate Stability• How do the Tropics differ in climate
from Temperate regions?
5. Competition Among Species
• Predators can enhance an area by reducing the population size of prey species
• Other species have a chance to get established
• Keystone Species have a large effect on the other species of a community– Oysters of the Chesapeake Bay– Vital as water filters, provide habitat, income
for watermen
6. The Nature of Disturbance
1. Damage communities
2. Remove organisms
3. Alter resource availability
FireFlooding
Storms and HurricanesTornados
Ice Storms
6. Disturbance
1. Create opportunities for the colonization of new species
2. Disturbance is a natural part of the life of a community: most communities are always in recovery from disturbance
3. Humans as agents of disturbance
Hurricane Katrina
• Cypress trees play a crucial role in the swamp forests that cover hundreds of thousands of acres of coastal Louisiana. These swamps prevent floods by collecting storm waters and clean water by filtering out pollution. They also provide habitat for a wide variety of animals, such as migratory songbirds (the ivory-billed woodpecker, until recently believed extinct, once thrived in the swamps).
FIREYellowstone fires of 1988
Fire has been used to manage marshes and forests
Optional ActivityUnit 3: Activity 31
Track Your UnderstandingAnswer Question #2 on pages 464-465
worth 5 points
Species Extinction:Past and Present
• Extinction is a biological reality• Extinction and evolution are intricately related• Five mass extinctions in the earth’s history
– 99% of species that have ever existed are now extinct
• Each mass extinction is followed by a rise in biodiversity of a new set of species
Humans Agents of Extinction
• Humans have played a role in the extinction of species for thousands of years
• Some say we are facilitating the 6th mass extinction in the earth’s history
• Can scientists accurately measure extinction rates?
Estimates of Extinction Rates“the logic of loss”
• Estimating rates is difficult at best• Most accurate estimates are for birds
and mammals• Species-area relationships from Island
Biogeography– # species is related to size of habitat– Estimate habitat loss– 90% habitat loss: 50% species loss
Island Biogeography:Species richness and island size
Conserving the Biodiversity of the Commons
• Conserving the world’s biodiversity is based on principles of biology– Population biology – Conservation biology
Principles of Population Biology
1. Small populations are more likely to become extinct than large populations
2. To understand a population it is important to consider factors such as its age structure and sex ratio
3. Populations must be monitored to determine the effects of a conservation plan
Principles of Conservation Biology
1. A species that is broadly distributed across its range is less likely to become extinct than a species that is restricted to a small part of its range
The range of the Eastern Fox Squirrel
• The Delmarva Fox Squirrel
• Original range included the entire Delmarva peninsula into southeastern PA.
• Remnant populations exist at Blackwater, Eastern Neck NWR (Kent Co.), and Assateague Island
Principles of Conservation Biology
2. Characteristics of habitats that favor species preservation:
a. Large rather than small; Bigger is better
b. Close together rather than far apart
c. Whole rather than internally fragmented
d. Linked by corridors rather than isolated
e. Inaccessible rather than easily accessible to people
• Island Biogeography (studying populations on islands) teaches us about conservation on main lands
• Why?• Habitat
fragmentation• Example
fragmenting a forest
• The main land of South America is to the Galapagos Islands as
• An intact forest is to the fragmented parcels
Dooms species by confining them to small, island-like parcels of habitat surrounded by an ocean of human impact. This often leads to: – Inbreeding within small populations– Roads, fences, houses, clear-cuts create
barriers to dispersal and reproduction– More susceptible to environmental
fluctuations and catastrophes
When habitats become islands
Habitat Loss and Fragmentation for Real
Corridors are Important for Connecting “Islands”
• Corridors function as pipelines that permit wildlife to move between habitats
• Promote biodiversity• But can also transmit disease, fire, predators, and
pests• The effectiveness of habitat corridors depends on the
situation
Agriculture with Forested Corridors
Algonquin to Adirondack
Wildlife Preservation Project
Fragmentation of Habitat in Maryland
• Early tobacco farming in the Mid-Atlantic resulted in fragmentation of the land into a fine mosaic of forest patches interspersed with young trees, herbs and shrubs.
• Large scale agriculture stripped extensive areas of the landscape leaving only small patches of forest
• The most extensive land clearance in the region occurred in the late 1800’s – early 1900’s
• 80% of the land around the Chesapeake was cleared of its forests.
• Wetlands were drained for farm land.
• The pattern of farm fields, forests, and marshes surrounding Blackwater Wildlife Refuge
• Dorchester Co. Eastern Shore
• Blackwater Wildlife Refuge’s Wildlife Drive is circled