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8/8/2019 ENVI SCI Lecture 4
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ENVIRONMENTAL SCIENCE 13e
CHAPTER 4:Biodiversity andEvolution
4-1 What Is Biodiversity andWhy Is It Important?
Concept 4-1 The biodiversity found in
genes, species, ecosystems, andecosystem processes is vital tosustaining life on earth.
Biodiversity (1)
Species diversity
A set of individuals that can mate andproduce fertile offspring
8-100 million species total; likely 10-14 million
2 million species identified
~50% in endangered tropicalrainforests
CLASSIFICATION OF LIVING
ORGANISM
Classification multilevel grouping ofindividuals
Organisms are first classified byAristotle
Classification scheme of the middle
ages (Polynomial) was replaced withBINOMIAL SYSTEM by Linnaeus
TAXONOMY.....
DESCRIPTION
IDENTIFICATION
NOMENCLATURE
CLASSIFICATION
ROOTLESS, STEMLESS, LEAFLESS
PLANT, PARASITIC, BROWNISH
SCALELIKE LEAVE, FOUL SMELLINGFLOWERS
RAFFLESSIA
Rafflessia arnoldii
FAMILY
RAFFLESIACEAE
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Species NamesFirst word of binomial name is Genus andis always capitalized
Second word refers to specific epithet and
is not capitalized
Together form scientific name, written initalics
A complete scientific name (BotanicalName) includes the authors name
Nepenthes madagascariensisPoir
Carl Linnaeus (1707-1778)
Father of Taxonomy
His system of
naming, ranking,and classifyingorganism is still inwide use today.
Before 1969, life was
classified into 2
kingdoms; the Plant
Kingdom and the Animal
Kingdom.
From 1969-1990, life was
classified into 5
kingdoms; Monera,
Protista, Fungi, Plants,
and Animal and some
accept the 6 kingdom
classification: Eubacteria,Archaeobacteria, Protista,
Fungi, Plantae and
Animalia.
1990 Life was classified into 3 Domains( by Carl Woese, 1990):
Domain 1. Archaea oldest known organisms appearing on a fossilrecord
over 3.6 million years ago.
Domain 2. Bacteria
Domain 3. Eucaryota
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Philippine Biodiversity:
Plant Diversity:
The flora of the Philippines iscomposed of at least 13,500
species that is 5% of the worldsflora:
- 8,000 flowering plant species (ofthese, 3200 endemic to thePhilippines)
- 3 gymnosperms (18 % endemic)
- 1,011 ferns and fern allies (30 %endemic)
- 806 mosses (23% endemic)
- 790 fungi
- Lichens -790
- 5-8% - not named yet.
Vertebrates, excluding freshwater fishes -
1090 species.
179 species of mammals (15 species still
to be named in 1995). 110 speciesendemic or 61 %.
558 species of birds (171 endemic
252 species of reptiles (159 endemic):
Lizards 126 species, (75% endemic)
Snakes 112 species (54% endemic)
Crocodiles -2 species (50% endemic)
Invertebrates:
2782 species of mollusks
54 millipedes
44 centipedes
20,000 insect species
341 species of spiders
Philippine Biodiversity
GENETIC DIVERSITY
Genetic Information in all cells
Deoxyribonucleic Acid
DNA contains instructions for traitsGENES
Make the structures and complexchemicals necessary for life
15
Genetic diversity
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Biodiversity (2)
Ecosystem diversity
Biomes Distinct climate
Certain species, especially vegetation
Functional diversity
Fig. 4-2, p. 61
Functional DiversityThe biological and chemical processes such as energyflow and matter recycling needed for the survival of species,communities, and ecosystems.
Genetic DiversityThe variety of genetic materialwithin a species or a population.
Species DiversityThe number and abundance of speciespresent in different communities
Ecological DiversityThe variety of terrestrial andaquatic ecosystems found inan area or on the earth.
Fig. 4-2, p. 61
Coastalmountainranges
Deciduousforest
Prairiegrassland
Coniferousforest
DesertConiferousforest
Coastal chaparraland scrub
AppalachianMountains
MississippiRiver Valley
GreatPlains
RockyMountains
GreatAmerican
Desert
SierraNevada
Fig. 4-4, p. 63
San Francisco
Las Vegas
Denver
St. Louis
Baltimore
Average annual precipitation
100-125 cm (40-50 in.)75-100 cm (30-40 in.)50-75 cm (20-30 in.)25-50 cm (10-20 in.)below-25 cm (0-10 in.)
Science Focus: Insects
Around for ~400 million years Bad reputation
Useful to humans and ecosystems
Vital roles in sustaining life
Pollinators
Natural pest control
Renewing soils
Fig. 4-A, p. 62
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Fig. 4-A, p. 62
4-2 How Does the Earths LifeChange over Time?
Concept 4-2A The scientific theory ofevolution explains how life on earth
changes over time through changes in thegenes of populations.
Concept 4-2B Populations evolve whengenes mutate and give some individuals
genetic traits that enhance their abilities tosurvive and to produce offspring withthese traits (natural selection).
Evolution
Populations of organisms
change (evolve) overgenerations (time)
Explains how many differentkinds of organisms cameinto existence SPECIES
Explains how modernorganisms are related topast organisms
27
Explains whyorganisms look andbehave the way they
do
Provides a basis forexploring therelationships among
different groups oforganisms
28
29
Evolve
Ability to adapt to their environment through theprocess of evolution
Favorable characteristics are selected for andpassed on to offspring
Called adaptations
Driven bynatural selectionor survival of thefittest
Natural Selection
Natural selection is the drivingforce in evolution
Organisms that have certain
favorable traits are better ableto successfully reproduce thanorganisms that lack these traits
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Natural Selection
Survival of organisms withfavorable traits cause a gradual
change in populations overmany generations
Also Called Survival of theFittest
31
Theory of Evolution
Fossils
Mineralized and petrified remains
Skeletons, bones, and shells
Leaves and seeds
Impressions in rocks
Fossil record incomplete: ~1% of allspecies
Charles Darwin, On the Origin ofSpecies, 1859
Population Changes over Time
Populations evolve by becominggenetically different over time
Genetic variability mutations
Random changes in DNA molecules ingenes
Can occur spontaneously
External agents: radiation Can create a heritable trait
Natural Selection
Adaptive traits - genetically favorabletraits that increase the probability to
survive and reproduce
Trait heritable and lead to differentialreproduction
Faced with environmental change
Adapt through evolution
Migrate
Become extinct
Three Myths about Evolutionthrough Natural Selection Refuted
1. Survival of the fittest does not meansurvival of the strongest
2. Organisms dont develop traits just
because they would be useful: giraffes
and long necks
3. There is no grand plan of nature tocreate more perfectly adapted species
no trend toward genetic perfection
4-3 How Do Geological Processes andClimate Changes Affect Evolution?
Concept 4-3Tectonic platemovements, volcanic eruptions,earthquakes, and climate changehave shifted wildlife habitats, wipedout large numbers of species, and
created opportunities for the evolutionof new species.
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Plate Tectonics
Effects on evolution
Locations of continents and oceansdetermine earths climate
Movement of continents allow species tomove and adapt
Earthquakes and volcanoes affect biological
evolution by separating populations of aspecies and allowing new species to develop
Present65 million years ago
135 million years ago225 million years ago
Fig. 4-6, p. 66
Earths Long-Term ClimateChanges
Cooling and warming periods affectevolution and extinction of species
Change ocean levels and area
Glaciers expanding and contracting
Climate changes
Opportunities for the evolution of new
species
Many species go extinct
18,000
years beforepresent
Modern day
(August)
Northern Hemisphere
Ice coverage
Fig. 4-7, p. 67
LegendContinental ice
Sea ice
Land above sea level
4-4 How Do Speciation, Extinction, andHuman Activities Affect Biodiversity?
Concept 4-4 Human activitiesdecrease the earths biodiversity bycausing the premature extinction ofspecies and by destroying ordegrading habitats needed for the
development of new species.
Speciation
Speciation One species splits into two or more
species that can no longer breed andproduce fertile offspring
Geographic isolation
Reproductive isolation
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Science Focus: ChangingGenetic Traits
Artificial selection
Selective breeding: crossbreeding varieties
within same species to enhance desired traits
Grains, fruits, vegetables, dogs, other animals
Genetic engineering
Add, delete, or alter DNA segments
Add desirable genes from other species
New drugs, pest-resistant plants
Controversial
Extinction (1)
Biological extinction Entire species gone
Local extinction All members of a species in a specific area
gone
Endemic species vulnerable to extinction
Background extinction
Speciation generally more rapid thanextinction
4-5 What Is Species Diversityand Why Is It Important?
Concept 4-5 Species diversity is amajor component of biodiversity andtends to increase the sustainability of
some ecosystems.
Species Diversity
Species richness
Species evenness
Varies with geographic location
Richness and Sustainability
Hypothesis Does a community with high species
richness have greater sustainability andproductivity?
Research suggests yes
4-6 What Roles Do SpeciesPlay in an Ecosystem?
Concept 4-6 Each species plays aspecific ecological role called itsniche.
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Ecological Niche (1)
Species occupy unique niches and playspecific roles in an ecosystem
Includes everything required for survivaland reproduction
Water
Sunlight
Space
Temperatures
Food requirements
Ecological Niche (2)
Generalist species
Specialist species Native species
Nonnative species
Spread in new, suitable niches