1 unit three evolution, biodiversity, and community processes a. c. mosley high school mrs. dow...
Post on 12-Jan-2016
214 Views
Preview:
TRANSCRIPT
1
Unit ThreeUnit Three
Evolution, Evolution, Biodiversity, and Biodiversity, and
Community ProcessesCommunity Processes A. C. Mosley High School
Mrs. Dow
Chapter 5
2
The Just-Right PlanetRead Case study on page 87.
3
Origins of Life (5-1)
Chemical evolution of organic Chemical evolution of organic molecules, biopolymers & molecules, biopolymers & systems systems
Took about 1 billion years!Took about 1 billion years!
4
Miller-Urey Experiment
conducted in 1953 by Stanley Miller with Harold Ureythe first experiment about the evolution of prebiotic chemicals and the origin of life on Earth
mixture of methane, ammonia, hydrogen, and water vapor introduced into a 5-liter flask (simulate the Earth's primitive, reducing atmosphere) energized by an electrical discharge apparatus to represent ultraviolet radiation from the Sunproducts were allowed to condense and collect in a lower flask which modeled a body of water on the Earth's surface
5
Miller-Urey Experiment
heat supplied to this flask recycled the water vapor just as water evaporates from lakes and seas, before moving into the atmosphere and condensing again as rainafter a day of continuous operation
• a thin layer of hydrocarbons on the surface of the water
after about a week of operation• a dark brown scum had collected in
the lower flask and was found to contain several types of amino acids, including glycine and alanine, together with sugars, tars, and various other unidentified organic chemicals
6
EVOLUTIONisGradual Change
EVOLUTIONisGradual Change
7
Origins of Life (5-1)Next, biological evolution
Single-celled prokaryotic bacteria single-celled eukaryotes multicellular organisms
Evidence from fossils, ice-core drilling, chemical analysis & DNA
8
Plants begininvadingland
Evolution and expansion of life
First fossilrecord ofanimals
Age of reptiles
Age of mammals
Insects and amphibians invade the land
Modern humans(Homo sapiens)appear about2 secondsbefore midnight
Recorded humanhistory begins1/4 secondbefore midnight
Origin of life(3.6–3.8 billionyears ago)
Page 89
noon
midnight
9
FossilsOldest fossils are the approximately 3.465 billion-year-old microfossils from the Apex Chert, Australia
colonies of cyanobacteria (formerly called blue-green algae) which
built real reefs
10
History of Theories of Evolution
11
Old Theories of Evolution
Jean Baptiste Lamarck (early 1800’s) proposed:
“The inheritance of acquired characteristics”
He proposed that by using or not using its body parts, an individual tends to develop certain
characteristics, which it passes on to its offspring.
Lamarck's scientific theories were largely ignored or attacked during his lifetime, Today, the name of Lamarck is associated merely with a discredited theory of heredity
12
“The Inheritance of Acquired Characteristics”
Example:
A giraffe acquired its long neck because its ancestor stretched higher and higher into
the trees to reach leaves, and that the animal’s increasingly lengthened neck was
passed on to its offspring.
13
14
Charles Darwin
Darwin set sail on the H.M.S. Beagle (1831-1836) to survey the south seas (mainly South America and the Galapagos Islands) to collect plants and animals.
On the Galapagos Islands, Darwin observed species that lived no where else in the world.
These observations led Darwin to write a book
15
Darwin’s Journey on the H.M.S. Beagle
16
Pinta IslandIntermediate shell
Pinta
Isabela IslandDome-shaped shell
Hood IslandSaddle-backed shell
HoodFloreana
Santa Fe
Santa Cruz
James
Marchena
Fernandina
Isabela
Tower
Giant Tortoises of the Galápagos Giant Tortoises of the Galápagos IslandsIslands
18
Charles Darwin
Wrote in 1859:
“On the Origin of Species by Means of Natural Selection”
Two main conclusions:
1. Species were not created in their present form, but evolved from ancestral species.
2. Proposed a mechanism for evolution: NATURAL SELECTION
19
Darwin’s ObservationsDarwin’s Observations
1.1. Most species produce more offspring Most species produce more offspring than can be supported by the than can be supported by the environmentenvironment
2.2. Environmental resources are limitedEnvironmental resources are limited3.3. Most populations are stable in sizeMost populations are stable in size4.4. Individuals vary greatly in their Individuals vary greatly in their
characteristics (phenotypes)characteristics (phenotypes)5.5. Variation is heritable (genotypes)Variation is heritable (genotypes)
20
Natural Selection
Individuals with favorable traits are more likely to leave more offspring better suited for their environment
Also known as “Differential Reproduction”
Example:
English peppered
moth (Biston betularia)
21
Evolution & Adaptation (5-2)Change in a population’s genetic makeup over timeTheory of evolution all species came from a earlier, ancestral species
Microevolution (genes mutate individuals are selected populations evolve)Small genetic changes over time (traits are passed on)
Sexual reproduction leads to diversityGene pool (all the genes in a populations offspring)Variability is created by mutations
DNA exposed to external agentsRandom mistakes
22
Microevolution- Microevolution works through a combination of
four processes that change the genetic composition of a population:
Mutation – involving random changes in the structure or number of DNA molecules in a cell and is the ultimate source of genetic variability in a population.
Natural selection – occurs when some individuals of a population have genetically based traits that cause them to survive and produce more offspring than other individuals
Gene flow – which involves movement of genes between populations and can lead to changes in the genetic composition of local populations.
Genetic drift – involves changes in the genetic composition of a population by chance and is especially important for small populations.
23
Natural selectionMembers of a population have favorable traits that are passed on3 necessary conditions
Must have genetic variabilityMust be heritableMust allow for further offspring
• Some mutations are harmful/some beneficial
24
Adaptive traits (adaptation)Heritable traits that help organisms survive and reproduce
Helps to:Adapt to new conditionsMigrate to a new areaBecome extinct
Adaptive Radiation
Emergence of numerous species from a common ancestor introduced to new and diverse environments
Example:
Hawaiian Honeycreepers
Convergent Evolution
Species from different evolutionary branches may come to resemble one another if they live
in very similar environments
Example:
1. Ostrich (Africa) and Emu (Australia).
2. Sidewinder (Mojave Desert) and
Horned Viper (Middle East Desert)
27
28
Three Types of Natural Selection and Co evolution
Three types of natural selection
Biologists recognize three types of natural selection – depending on environmental conditions.
1. Directional natural selection
2. Stabilizing natural selection
3. Diversifying natural selection
29
Click to view animation.
Example of directional selection animation.
Animation (watch on CD)
30
Animation (watch on CD)
Click to view animation.
Stabilizing selection animation.
31
Animation (watch on CD)
Click to view animation.
Disruptive selection animation.
32
What is co evolution?What is co evolution?
It is an evolution in which two or more It is an evolution in which two or more species interact and exert selective species interact and exert selective pressures on each other that can lead pressures on each other that can lead each species to undergo various each species to undergo various adaptations. adaptations.
Bats and Moths
Coevolution
Evolutionary changeOne species acts as a selective force on a second speciesInducing adaptations that act as selective force on the first species
Example:1. Wolf and Moose2. Acacia ants and Acacia trees2. Yucca Plants and Yucca moths3. Lichen
34
35
Ecological Niches and Adaptation (5-3)
NicheSpecies way of life and every thing that affects it
Includes member’s adaptations
Range of tolerance
Role of energy flow
HabitatWhere an organism lives
Conditions and resources it needs
36
Niche isthe species’ occupation and its
Habitat location of species
(its address)
37
Niche
Realized niche:Realized niche: more restricted more restricted set of conditions under which set of conditions under which the species actually exists due to the species actually exists due to interactions with other speciesinteractions with other species
Fundamental niche:Fundamental niche: set of set of conditions under which a conditions under which a species might exist in the species might exist in the absence of interactions with absence of interactions with other speciesother species
38
GeneralistsBroad ecological role
Living in many places
Eat a variety of foods
Will adapt easily
Ability to develop genetic resistance to poisons
39
SpecialistsSpecialistsLive in specific environmentsLive in specific environmentsProne to extinctionProne to extinctionCompetition may cause them to Competition may cause them to evolveevolve
Panda eat mostly bamboo, are Panda eat mostly bamboo, are separated into small isolated separated into small isolated groups and have low birth rates groups and have low birth rates and litter size and litter size Organism is classified a generalist or a
specialist based on its
Range of toleranceNicheLimiting factorsResponse to changing conditions
40
Region of niche overlap
Generalist specieswith a broad nicheSpecialist species
with a narrow nicheNiche
breadth
Nicheseparation
Num
ber
of in
divi
dual
s
Resource use
Overlap of the niches of two different species
41
Specialized feeding niches of various birds species in a coastal wetland
Black skimmerseizes small fishat water surface
Flamingofeeds on minuteorganismsin mud
Scaup and otherdiving ducks feed onmollusks, crustaceans,and aquatic vegetation
Brown pelican dives for fish,which it locates from the air
Avocet sweeps bill throughmud and surface water in search of small crustaceans,insects, and seeds
Louisiana heron wades intowater to seize small fish
Oystercatcher feeds onclams, mussels, and other shellfish into which it pries its narrow beak
Dowitcher probes deeplyinto mud in search ofsnails, marine worms,and small crustaceans
Knot (a sandpiper) picks upworms and small crustaceansleft by receding tide
Herring gull is atireless scavenger
Ruddy turnstone searchesunder shells and pebbles for small invertebrates
Piping plover feedson insects and tinycrustaceans on sandy beaches
Resource partitioning reduces competition
42
“Evolution is concerned about leaving the most descendents, not the strongest”
43
MacroevolutionWhat is macroevolution?
Macroevolution is concerned with how evolution takes place above the level of species and over much longer periods than microevolution, and macro evolutionary patterns include genetic persistence, genetic divergence, and genetic loss.
44
Speciation, Extinction and Biodiversity (5-4)
SpeciationTwo species arise when two species can no longer breed
• Allopatric speciation Due to geographical isolation or reproductive isolation Fox population (next slide)
• Sympatric speciation Two species live close together, can’t interbreed Example: some insects when two populations experience
different types of mutations by feeding on different types of plants
45
Early foxpopulation
Spreadsnorthwardandsouthwardandseparates
How geographic isolation can lead to reproductive
isolation, divergence, and speciation.
Adapted to heatthrough lightweightfur and long ears, legs, and nose, whichgive off more heat.
Adapted to cold through heavier fur, short ears,short legs, short nose. White fur matches snow for camouflage.
Gray Fox
Arctic Fox
Different environmentalconditions lead to differentselective pressures and evolutioninto two different species.
Northernpopulation
Southernpopulation
Grey Fox
46
Going, Going, Gone
Extinction Natural disasters
Introduction of new competitive species
Environmental changes
Adaptive radiationRecovery periods after mass extinction
It takes 1 to 10 million years to rebuild biological diversity of a mass extinction
47
Biologist estimate that 99.9% of all the species that ever existed are extinct.
When local environmental changes, some species will disappear at a low rate: this is called background extinctionMass extinction is a significant rise in extinction rates above the background extinction (usually 25-70% species lost)Mass depletion extinction rates are higher than normal but not high enough to classify as a mass extinction
48
Mass Extinctions & Depletion2 Mass extinction & 3 Mass depletions
Date of the Extinction Event
Percent Species
Lost Species Affected
65 mya
(million
years ago)
85 Dinosaurs, plants (except ferns and seed bearing plants), marine vertebrates and invertebrates. Most mammals,
birds, turtles, crocodiles, lizards, snakes, and amphibians were unaffected.
213 mya 44 Marine vertebrates and invertebrates
248 mya 75-95 Marine vertebrates and invertebrates
380 mya 70 Marine invertebrates
450 mya 50 Marine invertebrates
http://www.geog.ouc.bc.ca/physgeog/contents/9h.html
50
EURASIA
AFRICASO
UTH
AM
ER
ICA
IND
IA
135 million years ago
Present65 million years ago
225 million years ago
120°80° 0°
120°120°
120°
80°80° 80°80°40°
40°120° 120°
120°GONDWANALANDGONDWANALAND
120°
LAURASIALAURASIA
PA
NG
AE
A
PA
NG
AE
A
ANTARCTICAANTARCTICA AUSTRALIA
AUSTRALIAMADA-
GASCARMADA-
GASCAR
Continental drift
51
Natural capitalTerrestrialorganisms
Marineorganisms
Qu
ate
rna
ry
Ter
tiar
yCre
tace
ou
s
Jura
ssic
Tri
assi
c
Per
mia
n
Car
bo
nif
ero
us
Dev
on
ian
Silu
rian
Ord
ovi
cian
Cam
bri
an
Pre
-cam
bra
in
1.8 06514520525029035541044050054535000
1600
1200
800
400
Nu
mb
er o
f fa
mili
es
Millions of years ago
Change in the earth’s biodiversity over geological
time.
52
Sustainability and EvolutionEarth is constantly changing, and throughout the earth’s history the atmosphere has changed, the climate has changed, the geography has changed he types and numbers of organisms have changes, and continental drift has changed the positions of the earth’s continents.
Biologists estimate that the current human-accelerated extinction rate of species is 1,000 to 10,000 times higher than natural extinction rates. (100 to 1,000 species per million species)
It has been predicted that by the end of the 21st century we may see the extinction of half of the present species now on Earth.
53
Future of Evolution? (5-5)
Artificial selection by humans
Selective breeding
Genetic breeding/gene splicingCloning
Biopharming
54
Genetic engineeringUnpredictable process
Ethical
Success rate is 1%
How will benefit?
55
Crop
Crossbreeding
Desired trait(color)
ApplePear
Offspring
Crossbreeding
Best results
Newoffspring
Desiredresult
Figure 5-10
Page 97
56
Phase 1Make Modified Gene
Identify and extractgene with desired trait
Identify and removeportion of DNAwith desired trait
Remove plasmidfrom DNA of E. coli
Insert extracted DNA(step 2) into plasmid(step3)
Insert modifiedplasmid into E. coli
Grow in tissueculture tomake copies
cell
gene
DNA
plasmid
E. coliDNA
Geneticallymodifiedplasmid
plasmid
57
Phase 2Make Transgenic Cell
Transfer plasmidcopies to a carrier
agrobacterium
Agrobacteriuminserts foreignDNA into plantcell to yieldtransgenic cell
Transfer plasmidto surfacemicroscopic metalparticle
Use gene gunto inject DNAinto plant cell
A. tumefaciens(agrobacterium)
Plant cell
Nucleus
Host DNA
Foreign DNA
Figure 5-11b Page 98
58
Phase 3Grow Genetically Engineered Plant
Transgenic cellfrom Phase 2
Cell division oftransgenic cells
Culture cellsto form plantlets
Transgenic plantswith new traits
Figure 5-11c Page 98
Transfer to soil
59
Animation (watch on CD)
Click to view animation.
Evolutionary tree of life animation.
60
Animation
Click to view animation.
Evolutionary tree diagrams interaction.
top related