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EVOLUTION: CHANGE OVER TIME. In Biology…evolution refers to:. Changes in SPECIES over time A species is a group of similar organisms that can breed and produce fertile offspring. CHARLES DARWIN. Proposed the theory of evolution

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in biology evolution refers to
In Biology…evolution refers to:
  • Changes in SPECIES over time
  • A species is a group of similar organisms that can breed and produce fertile offspring.
charles darwin
CHARLES DARWIN
  • Proposed the theory of evolution
  • He made observations on his voyage around the world…collecting evidence to develop his theory.
  • On the Origin of Species (Book—1859)
important observations
IMPORTANT OBSERVATIONS
  • Noticed a great diversity among a number of species.
  • Plants and animals were suited to the environment in which they lived.
  • Different species lived in similar ecosystems.
fossil record
FOSSIL RECORD
  • A fossil is the preserved remains of ancient organisms.
    • Some looked like modern animals
    • Some looked different than any modern organisms
the galapagos islands
The Galapagos Islands
  • Very close to one another…but their climates differed greatly-
    • Low elevation: very dry, hot, sparsely vegetated
    • Higher elevation: a lot of rainfall, more diverse plant life
galapagos tortoises
Galapagos Tortoises

Saddleback Domed

fitness
FITNESS
  • Organisms compete to survive and reproduce
  • Organisms best suited to their environments are most likely to succeed
fitness is attributed to
FITNESS is attributed to:
  • Adaptations
    • Any inherited trait that increases an organism’s chance of survival
natural selection
NATURAL SELECTION
  • SURVIVAL OF THE FITTEST—
    • Those that are able to survive will be able to reproduce and pass on their adaptations to the next generation
natural selection 4 principles
NATURAL SELECTION (4 Principles)
  • VARIATION EXISTS WITHIN POPULATIONS
natural selection 4 principles1
NATURAL SELECTION (4 Principles)

2. ORGANISMS COMPETE FOR LIMITED NATURAL RESOURCES

natural selection 4 principles2
NATURAL SELECTION (4 Principles)

3. ORGANISMS PRODUCE MORE OFFSPRING THAN CAN SURVIVE

natural selection 4 principles3
NATURAL SELECTION (4 Principles)

4. INDIVIDUALS WITH VARIATIONS SUITABLE FOR THEIR HABITAT SURVIVE AND REPRODUCE

two ways evolution may occur
TWO WAYS EVOLUTION MAY OCCUR
  • GRADUALISM
    • Occurs over a long period of time
  • PUNCTUATEDEQUILIBRIUM
    • Occurs in spurts
    • Caused by:
      • Random change in DNA
      • Sudden environmental changes
two forms of evolution
TWO FORMS OF EVOLUTION
  • MACROEVOLUTION
    • changes that occur on the tree of life
  • MICROEVOLUTION
    • Changes that occur within a population
    • (group of individuals of the same species living in the same area)
slide22

Genetic variation is caused by changes in genetic frequency—there are 5 forces of genetic change:

1. Natural Selection

2. Mutations

3. Gene flow

4. Genetic drift

5. Nonrandom mating

mutations
MUTATIONS
  • Change in DNA sequence
    • Deletion
    • Inversion
    • Translocation
    • Duplication

…however…

mutations1
MUTATIONS
  • To affect evolution, mutations must be passed on from one generation to the next…
  • Only mutations in gametes can be passed on…
  • …to affect evolution!
gene flow
GENE FLOW
  • Genes from one population are introduced into the gene pool of another
  • GENE POOL: combined genetic info of all members
  • Basically affected by migration
genetic drift
GENETIC DRIFT
  • Changing the allele frequency
  • Some individuals may have more offspring than others
bottleneck effect
BOTTLENECK EFFECT
  • A form of genetic drift
  • Sudden and severe decrease in a population size that results from natural disaster, predation, or habitat reduction.
founder s effect
FOUNDER’S EFFECT
  • A form of genetic drift
  • occurs when a new isolated population is founded by a small number of individuals possessing limited genetic variation

(relative to the larger population from which they have migrated)

founder s effect1
Founder’s Effect

http://upload.wikimedia.org/wikipedia/commons/2/24/Founder_effect-anim.gif

nonrandom mating
NONRANDOM MATING
  • Not all individuals have the opportunity to contribute their genes to the next generation (decreasing their allele frequency)
  • Courtship rituals, pecking orders, breeding territories
mechanisms of change
MECHANISMS OF CHANGE

MUTATIONS

GENE FLOW (MIGRATION)

GENETIC DRIFT

NATURAL SELECTION

slide35

Number of current classified species =

  • 2.1 million
  • Organisms that are not capable of breeding with each other belong to a different species
slide36

What causes new species to form?

                  • The evolutionary process called SPECIATION forms new species.
                  • New species evolve in 3 ways….
1 geographic isolation
1. GEOGRAPHIC ISOLATION
  • A population is divided by a barrier
  • Two geographically isolated populations can no longer reach each other to breed
  • Natural selection on each side causes the populations to become genetically different
2 parapatric speciation
2. PARAPATRIC SPECIATION
  • Two neighboring populations
    • One hot and dry
    • One cooler and wet
  • Natural selection favors different adaptations in area
    • Causing genetic differences
  • At the boundary—individuals breed and make hybrids…
3 behavioral isolation
3. BEHAVIORAL ISOLATION
  • Differences among individuals cause them to choose different mates.
  • Continual, nonrandom mating causes individuals to become genetically different.
extinction
EXTINCTION
  • The death of all individuals within a species.
  • No longer able to survive changing environmental conditions

-or-

  • No longer able to compete
field of palentology
FIELD OF PALENTOLOGY
  • Fossils are “dead remains” that prove organisms existed
  • Give information about the age of organism (dating)
  • PROBLEMS??
    • Still missing links
    • Haven’t found all remains
field of biogeography
FIELD OF BIOGEOGRAPHY
  • Geographic distribution of organisms
  • Grouped according to the needs of habitats, resources
  • Similar organisms will arise in the same geographic location
slide47

Rhea (South America)

Emu (Australia)

Ostrich (Africa)

field of biochemistry
FIELD OF BIOCHEMISTRY
  • All living things have DNA
  • Organisms that show close relationships have similar protein and DNA structures
field of anatomy
FIELD OF ANATOMY

1. Homologousstructures

  • Have similar construction
  • Example:
    • Human arm
    • Cat leg
    • Whale flipper
    • Bat wing
field of anatomy1
FIELD OF ANATOMY

2. Analogous structures

  • Serve the same purpose
  • BUT not designed in same way
  • Example:
    • Bird wing
    • Insect wing
    • Bat wing
field of anatomy2
FIELD OF ANATOMY

3. Vestigial structures

  • Seen in organisms of today but not used
  • Example:
    • Appendix
    • Tail bone
    • Whale legs
    • Snake legs
field of embryology
FIELD OF EMBRYOLOGY
  • (embryo development)
  • Very early stages of development in animals are hard to distinguish between different animals
embryological homology
EMBRYOLOGICAL HOMOLOGY

IDENTIFY THE ORGANISMS

coevolution
COEVOLUTION
  • Change in two or more species in close association with each other
  • Change occurs to benefit each other
  • EXAMPLE:
    • Animals and their plants
    • Hummingbird and trumpet flower
divergent evolution
DIVERGENT EVOLUTION
  • Two or more related species become different
convergent evolution
CONVERGENT EVOLUTION
  • Ancestors were different and become similar
diversity1
DIVERSITY
  • TAXONOMY
    • Science of naming and then classifying living things
  • CLASSIFICATION
    • Systematic grouping of organisms based on common characteristics
slide70

Kingdom

  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

Kids Prefer Cheese Over Fried Green Spinach

slide71

Scientists attempt to understand the evolutionary relationships among organisms…

  • PHYLOGENETICS
    • Studies the relationships among organisms
slide72

PHYLOGENETIC TREE:

    • Diagram that represents the evolutionary history of a species
phylogenetic trees are used to classify
PHYLOGENETIC TREES ARE USED TO CLASSIFY:
  • Organisms into major taxa (groups) based on evolutionary relationships
  • Species in the order in which they descended from a common ancestor using physical characteristics
phylogenetic tree3
PHYLOGENETIC TREE
  • Which groups are most closely related?
  • Which groups are least closely related?
  • Which group diverged first (longest ago) in the lineage?
slide83

Discuss Darwin’s contributions to how living things change over time.

  • Discuss evidence for how living things change over time—including homology, biogeography and fossil record.
  • Discuss the five conditions preventing living things from changing over time (Hardy-Weinberg). What conclusions can you draw based on this information?
  • There are several agents (mechanisms) for how living things change over time, focus your research on the following: genetic drift (including the founder’s effect and bottleneck effect) and gene flow.
  • There are several agents (mechanisms) for how living things change over time, focus your research on the following: natural selection and mutations.
  • What misconceptions did you have prior to your research? What are your conclusions?
hardy weinberg
Hardy-Weinberg
  • What Is Hardy-Weinberg?
  • How does it work?
hardy weinberg conditions
Hardy-Weinberg Conditions
  • No Genetic Drift (Infinite Population Size)

2. No Migration (No Gene Flow)

3. No Mutation

4. No Selection (No Differential Selection)

5. Random Mating (No Differential Reproduction)

slide89

All blue-eyed people can be traced back to one ancestor who lived 10,000 years ago near the Black SeaBy MICHAEL HANLON

Everyone with blue eyes can be traced back 10,000 years to the Black Sea region. Throughout history they have been the eyes that are prized. Frank Sinatra\'s were legendary, Paul Newman\'s melted a million hearts while Cameron Diaz\'s dazzle in modern Hollywood.But how - and why - blue eyes arose has always been something of a genetic mystery. Until now.According to a team of researchers from Copenhagen University, a single mutation which arose as recently as 6-10,000 years ago was responsible for all the blue-eyed people alive on Earth today.The team identified a single mutation in a gene called OCA2, which arose by chance somewhere around the northwest coasts of the Black Sea in one single individual, about 8,000 years ago.The gene does not "make" blue in the iris; rather, it turns off the mechanism which produces brown melanin pigment. "Originally, we all had brown eyes," says Dr Hans Eiberg, who led the team.And most people still do. The finding that a rare mutation, probably dispersed in the rapid wave of colonization that followed the end of the last ice age, highlights one of the great mysteries of human evolution: the oddness of Europeans. One theory is that Europe\'s cold weather and dark skies played a part. Fair skin is better at making Vitamin D from the 8 per cent of the world\'s population have blue eyes weak sunlight found in northern latitudes. Perhaps the most plausible theory is that blonde hair and blue eyes arose because of a mechanism called sex selection.This is where males and females choose as their mates those who have one unusual physical characteristic, not necessarily associated with "fitness" per se but simply something unusual.The gigantic (and otherwise useless) tail of the peacock is the best example.

images
IMAGES
  • ANATOMICAL HOMOLOGY
  • EMBRYOLOGICAL HOMOLOGY
  • VARIATION
  • MECHANISMS OF CHANGE
  • NATURAL SELECTION
  • FINCHES
  • GIRAFFES
  • THE NEW FACE OF AMERICA
  • BLUE EYES
  • FROGS
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