Transcript PPT Review 2

Chapter 5,9 &10:
Review…How do we get
Bio Diversity
Biodiversity of life.. Habitats
• Climate
and Natural Selection
What is Biological Diversity
• Bio diversity refers to the variety of life
forms in an area.
– Expressed as # of species in an area
– Or # of genetic types in an area
Natural Selection
• Some individuals may be better suited to the
environment than others.
• Those better able to survive and reproduce
leave more offspring.
• Their descendants form a larger proportion
of the next generation.
Mutation
• Genes are inherited from one generation to the next
– Genes made up of DNA
– DNA made up bases A,C,G,T
• How these letters are combined determines the massage
passed to a cell
• When cells divide
– DNA is reproduced
– Each cell gets a copy
• If an error occurs in the reproduction of DNA it gets
passed to new cells
• DNA change = Mutation
Mutation
Natural Selection
• Four primary characteristics
– Genetic variability
– Environmental variability causes pressure
Adaptations determined
– Differential success and reproduction
– Survival and reproduction to pass on
adaptations
Basic Concepts of Biological
Diversity
• Genetic diversity:
– total # of genetic characteristics of a specific species,
sub species or group of species.
• Habitat diversity:
– the different kinds of habitat in a given unit area.
• Species diversity:
– Species richness- total # of sp
– Species evenness- the relative abundance of sp
– Species dominance- the most abundant sp
Species Diversity
Merely counting the number of species is not enough to
describe biological diversity.
The Evolution of Life on Earth
• Earliest fossils 3.5 billion years old
– Photosynthetic relative of bacteria
– Released large amounts of oxygen into the
atmosphere
The Evolution of Life on Earth
• Cambrian Period 600 million years- 500 my
– Earliest multicellular organisms
– Shells, gills, filters, efficient guts and circulatory system.
– Life remained in oceans
The Evolution of Life on
Earth
•
Devonian Period
– 420–360 million years ago
– First animals on land = crossopterygian
– Gave rise to the amphibians
• Still tied to water for reproduction
• Modern species include frogs, toads, newts, limbless
water “snakes”
Early Life on Land
Innovations for life on land
Structural support
Avoid dessication and UV rays
Means for exchanging gases with air
A moist environment for reproduction system
The Evolution of Life on Earth
• Reptiles
–
–
–
–
Freed from water by evolving a watertight egg
Originate in the Carboniferous (375 mya)
Wide spread by the Jurassic (185 mya)
Two orders of dinosaurs that gave rise to
mammal and birds.
The Evolution of Life on Earth
• Mammals
– More capable brain and
faster metabolism
– Placental uterus one
key to mammalian
success
Virginia
California
Island Biogeography
• Islands have fewer species than continents
– The smaller the island the fewer the species
– The farther away from a continent the fewer the
species
– Theory of island biogeography
Island Biogeography
• Small islands tend to have fewer habitat
types
• A small population easily wiped out by a
storm, flood, catastrophe or disturbance.
– The smaller the pop the greater the risk of
extinction
• The farther an island is from the mainland
the harder it is to reach.
Environmental Factors that Influence
Diversity
Earth’s Biomes
• 17 major biomes
• Usually named for the
– dominant vegetation type
– dominant shape or form of the dominant
organisms
– dominant climatic conditions
Biomes show up on Earth satellite image.
Earth’s Biomes
• Biological diversity varies among biomes
– Generally declines with increasing latitude
• Two theories
– The more favorable the temperature and
precipitation for life the more diversity.
– Greater the variability of climate, the lower the
diversity
Tundra
• Treeless plains that occur in harsh climates of low
rainfall and low average temperature.
• Dominant vegetation
– Grasses, sedges, mosses, lichens, dwarf shrubs and
mat-forming plants
• Permafrost- permanently frozen ground
– Extremely fragile, long recovery time
• Soil-dark thick soil of peat, poorly decomposed
Tundra Biome
Taiga or Boreal Forest
• Includes forests of the cold climates of high
latitudes and high altitudes
• Dominant vegetation
– Conifers, especially spruces, firs, larches and some
pines
– Biodiversity is low (20 major species)
• Dominant animals
– Few lg mammals, sm carnivores, sm rodents
– Many insects and migratory birds
• Soil- thin, nutrient poor
Moose in taiga biome.
Taiga or Boreal Forest
• Disturbances common
– Fire, storms, insects
• Contain some of Earth’s largest remaining
wilderness areas.
• Commercial value
Temperate Deciduous Forests
• Occur in climates somewhat warmer than those of
boreal forest.
• Dominant vegetation
– Tall deciduous trees (maple, beech, oak, hickory, and
chestnut)
• Dominant animals
– Tend to be small mammals
– Birds and insects
• Few undisturbed stands of forest left
• Soil-fertile, rich,
Temperate Rain Forest
• Occur where temperatures are moderate and
precipitation exceeds 250 cm/year.
• Dominant vegetation
– Evergreen conifers (some of the tallest trees in
the world)
• Low diversity of plants and animals
• Important economically and culturally
Temperate Rain
Forest
Temperate Grasslands
• Occur in regions too dry for forests and too moist
for deserts.
• Dominant vegetation
– Grasses and flowering plants
• Many converted to agriculture
– deep, rich soils
• Highest abundance and greatest diversity of large
mammals
– Grasses and grazers evolved together
Fire is important for the maintenance of Temperate Grasslands
Tropical Rain Forests
• Occur where the average temperature and
rainfall are high and relatively constant
throughout the year.
• Famous for their diversity of vegetation
– 2/3 of known flowering plants
– Many species of animals as well
• Soils low in nutrients
Tropical Rain Forest
Deserts
• Occur in the driest regions where rainfall is
less then 50 cm/year.
• Specialized vegetation, vertebrates and
invertebrates.
– Water conservers
• Soils has low organic matter but abundant
nutrients
– Need only water to become productive
Desert Biome
Wetlands
• Include freshwater swamp, marshes and
bogs and saltwater marshes.
– All have standing water
• Dominant vegetation
– Small tress (mangroves) to shrubs, sedges and
mosses
Wetlands
• Soil has little oxygen
– Bacteria that produce methane and hydrogen
sulfide
– Coal bed production
• Dominant animals
– Salt water marshes- Crabs, clams
– Freshwater wetlands- insects, birds and
amphibians
Freshwaters
• Freshwater lakes, ponds, rivers, and streams
– Make up a very small portion of Earth’s surface
– Critical for water supply, material transport
• Dominants
– Floating algae, phytoplankton
– Abundant animal life
Freshwater
• Estuaries- areas at the mouths of rivers
– Rich in nutrients
– Abundance of fish and important breeding sites
for fish
• Freshwater among the most important
biomes for life’s diversity.
Intertidal Areas
• Areas exposed alternately to air during low
tide and ocean waters during high tide.
• Constant flow of nutrients into and out of
area.
– Rich in life
• Susceptible to pollution
• Adaptation to disturbances is essential to
survival in this biome.
The Process of Ecological
Succession
• Recovery of disturbed ecosystems can occur
naturally, through a process of ecological
succession.
• Primary succession
– The initial establishment and development of an
ecosystem where one did not exist previously
• Secondary succession
– Reestablishment of an ecosystem following
disturbance
Examples of primary succession
after a lava flow and at the edge
of a receding glacier.
Secondary successionfrom abandoned field to
mature forest
Patterns of Succession
• When succession occurs it follows certain
general patterns.
– Three examples include dunes, bog and
abandoned farm field
Dune Succession
• Sand dunes continually formed along sandy
shores.
– Then breached and destroyed by storms
• After dune forms
– First to be established are grasses
– Grass runners stabilize dunes
– Other species seeds may germinate and become
established
Dune Succession
• Plants of early succession tend to be
– Small, grow well in bright light, and withstand
harshness of environment
• Over time larger plants can become
established
– Eastern red cedar, eastern white pine
– Beech and maple later on
Bog Succession
• A bog is an open body of water with surface
inlets but no surface outlets.
• Succession begins with
– Sedge puts out floating runners
– Wind blows particles into the mat of runners
– Seeds that land on top don’t sink in the water
and can germinate
– Mat becomes thicker and shrubs and trees can
grow
Bog Succession
• The bog also fills in from the bottom
– The the shoreward end floating mat and
sediment will meet, forming a solid surface.
– Farther from shore all the vegetation is still
floating
Old-Field Succession
• A great deal of land cleared for farming in
the 18th and 19th centuries
– That land now allowed to go back to forest
• Succession
– The first plants to enter the farm land are small
plants adapted to harsh and variable conditions.
– After they are established larger plants move in.
These habitats are constantly changing
General Patterns of Succession
• Common element include the following
– 1. An initial kind of vegetation specially
adapted to the unstable conditions.
• Typically small
• Help stabilize physical environment
– 2. A second stage with plants still of small
statute, rapidly growing, with seeds that spread
rapidly.
General Patterns of Succession
– 3. A third stage in which larger plants,
including trees, enter and begin to dominate the
site.
– 4. A forth stage in which mature forest
develops.
General Patterns of Succession
• Successional stages
– Early (1 and 2), middle, and late
• Similar patterns seen with animals and other
life-forms at each stage.
– Species characteristic of early stage are called
pioneers
– Late-successional species tend to be slowergrowing and longer-lived
General Patterns of Succession
• In early stages of succession
– Biomass and biological diversity increase
• In middle stages
– Gross production increase and net production
decrease
– Organic material in soil increases, as does
chemical element storage
Succession and Chemical
Cycling
• The chemical storage capacity of soils varies w/
average size of the soil particle.
– Large coarse particles, like sand, have a smaller total
surface area and can store a smaller quantity of
chemical elements.
– Smaller particles, like clay, store greater quantity of
chemical elements.
• Soils store large quantities of c.e. but not as
readily available as those in living organisms.
Species Change in Succession
• Earlier and later species in succession may
interact in three ways
– Facilitation
– Interference
– Life history differences
• If they don’t interact the result is chronic
patchiness
Interaction between Species
• Competition
– The outcome is negative for both groups
• Symbiosis
– Close relationship between two organisms
parasitism, commensalism, muturalism
• Predation and parasitism
– The outcome benefits one and is detrimental to
the other.
Competitive Exclusion Principle
• Two species that have exactly the same
requirements cannot coexist in exactly the
same habitat.
– E.g. British Red Squirrel and American Grey
Squirrel
Symbiosis
• Describes a relationship between two
organisms
– beneficial to both
– enhances each organism’s chance of persisting
• Each partner called a symbiont
• E.g. reindeer and bacteria in the gut
– The result is food for reindeer, home for
bacteria
Lead into Chapter 12 Food
Predation and Parasitism
• Relationship is beneficial for predator or
parasite and negative for prey or host.
• Predation
– One organism (predator) feeds on other live
organisms (prey).
• Parasitism
– One organism (the parasite) lives on, in, or
within another (the host).
North Woods Ecosystem Population Fluctuations
Carrying Capacity
-------------------------------------------------K-species
exponential
r-species
Lead into Chapter 12 Food
Two Kinds of Biological
Production
Consider Food Webs
• Autotrophs
– Make their own organic matter from energy
source and inorganic compounds
– Primary production
– Most photosynthesize, some chemoautotrophs
• Heterotrophs
– Cannot make their own organic compounds and
must feed on other living things
– Secondary production
The Food Web of the Harp Seal
• Food webs are complex because most
species feed on several trophic levels.
• Harp seal (shown at 5th level)
– Feeds on flatfish (4th level)
– But also feed on foods from 2nd – 4th
– A species that feeds on several levels placed in
a category one above the highest level it feeds
on.
Chemosynthetic Energy Flow in
the Ocean
• Chemosynthetic organisms make their own
food from energy in sulfur compounds.
– Sulfur-laden water is emitted from hot water
vents
– Rich biological communities surround the vents
– Clams, mussels, crabs, limpets, fish, octopuses
and giant worms.
Balance of Nature
• Since the second half of the 20th century
ecologist have learned that nature is not
constant.
– All ecosystems undergo change
– Species adapted to and need change
• Dealing with change poses questions of
human value
– Controlling and managing fire
Community Level Interactions
• Indirect and more complicated community wide
affects species have on one another.
• Sea otter of the Pacific Ocean
– Came close to extinction because of over hunting for
fur
– Feed on shellfish (abalone, sea urchins)
– Where sea otters abundant kelp beds abundant and few
sea urchins
– Otters affects the abundance of kelp
Community Level Interactions
• Sea otters have community level effect
– Where more kelp is present more habitat for
many species
• Keystone species
– A species that has a large effect on its
community or ecosystem
• Holistic view
– Ecological community is more than the sum of
its parts