BIOLOGY CH16 EVOLUTIONNAME______
10pts
ESSENTIAL QUESTIONS
1. Who was Charles Darwin and what is his theory of Descent with Modification?
2. What is Evolution and how do mutations allow it to happen?
3. Are humans still evolving? Why or Why not?
4. Why is the concept of Evolution just a theory and not considered a Scientific Law?
What is the difference between these two types of Scientific Certainty?
BIOLOGY CH16 EVOLUTIONARY THEORYNAME______
BRIEFLY DESCRIBE THE FOLLOWING SCIENCETISTS INFLUENCE ON DARWIN’S THINKING
1. LAMARCK
2. LYELL & HUTTON
3. CUVIER
4. MALTHUS
5. DEFINE NATURAL SELECTION
WHAT ARE THE 4 STEPS OF EVOLUTION THROUGH NATURAL SELECTION?
BRIEFLY DESCRIBE EACH:
6.
7.
8.
9.
10. WHAT FIELDS OF SCIENCE DOES DARWINS IDEA UNIFY?
BIOLOGY CH16 EVOLUTIONNAME______
15pts Feel Free to use the power-point (Found on the calendar)or any materials I have given you to answer the questions.
ESSENTIAL QUESTIONS
1. What are the 5 types of evidence used to support the theory of evolution? Give a brief definition with examples for each
a.
b.
c.
d.
e.
2. What is anAdaptation?
3. What are the three types of Adaptations and describe each with an example
a.
b.
c.
4. What is Speciation and how does it happen?
5. What are the 5 types of evolution? Give an example for each
a.
b.
c.
d.
e.
BIOLOGY CH16 VOCABULARY
CHARLES DARWIN : The Father of Evolution through Natural Selection, he observed change through “Descent with Modification.” Wrote on the Origin of Species in 1859
SPECIES : Organisms so similar they can interbreed and produce VIABLE (fertile) offspring
NATURAL SELECTION: greater reproductive success displayed by individuals with ADAPTIVE traits
VARIATION: differences within a population
ADAPTATIONS: traits that are selected for because they help an organism survive and reproduce
EVOLUTION: Changes in species over time- Occurs when genes in a population change/shift to enhance survival and reproduction
JEAN BAPTISTE LAMARCK: Observed organisms change/evolve by passing down AQUIRED TRAITS
LYELL AND HUTTON: Geologists who proposed GRADUALISM as the source of change
CUVIER: Geologist who proposed CATASTROPHISM as the source of change
EVIDENCE FOR EVOLUTION: Comes from Fossils, Comparative Anatomy, Embryology, Biochemistry, Biogeography, and others!
EVIDENCE FOR EVOLUTION
FOSSIL EVIDENCE: Records of past organisms show common ancestry
COMPARATIVE ANATOMY: the study of similarities in organisms of common ancestry
Vestigial Structures- appendix, whale pelvis Analogous Structures – bee wing v. bird wing
Homologous structure - your hands-whale flipper
EMBRYOLOGY: The study of how embryos develop to show common ancestry- you had gills and a tail!
BIOCHEMISTRY: The similarity in gene sequence
BIOGEOGRAPHY: The study of how organisms are distributed today and in the fossil record
3 TYPES OF ADAPTATIONS
STRUCTURAL ADAPTATIONS: Physical feature like a wing to fly or fins to swim
PHYSIOLOGICAL ADAPTATION: Body functions like the production of venom or the ability to tolerate heat
BEHAVIORAL ADAPTATION: When organisms work together like a wolf pack, or school of fish
3 TYPES OFNATURAL SELECTION
DIRECTIONAL SELECTION: When a direction in phenotypes is favored- bigger brains
STABILIZING SELECTION: When 1 average phenotype is selected for – 7lb babys
DISRUPTIVE SELECTION: When 2 extreme phenotypes are selected for simultaneously- different colored butterflies
SPECIATION: The formation of new species through evolution
5 TYPES OF EVOLUTION
DIVERGENT: When new species are formed that have different features- Tiger & Lion
CONVERGENT: When species change to be similar to other species- Kangaroo & Deer
ADAPTIVE RADIATION: When species form to fill new or open ecological niches- Darwin’s Finches
COEVOLUTION: When species evolve together and rely on one another for survival- birds & flowers
EXTINCTION: When species evolutionary sequence ends-99% of all species over time have become extinct
EVOLUTION
BIO.B.3.1.1: Explain how natural selection can impact allele frequencies of a population.
BIO.B.3.1.2: Describe the factors that can contribute to the development of new species (isolating mechanisms, genetic drift, founder effect, migration).
BIO.B.3.1.3: Explain how genetic mutations may result in genotypic and phenotypic variations within a population.
BIO.B.3.2.1: Interpret evidence supporting the theory of evolution (fossil, anatomical, physiological, embryological, biochemical, and genetic code).
BIO.B.3.3.1: Distinguish among the scientific terms: hypothesis, inference, law, theory, principle, fact, and observation.
BIO.B.1.2.1: Describe how the process of DNA replication results in the transmission and/or conservation of genetic information.
BIOCH16NAME______
POWERPOINT OUTLINEChapter 16 Evolution
ESSENTIAL QUESTIONS
Who was Charles Darwin and what is his theory of Natural Selection
What is Evolution and how do mutations allow it to happen?
Are humans still evolving?
Why or Why not?
Why is the concept of Evolution just a theory and not considered a Scientific Law?
What is the difference between these two types of Scientific Certainty?
Chapter 16 Evolution
Charles Darwin is the father of evolutionary theory!
MUTATIONS are natural changes in organisms, occasionally(very rarely,) they’re beneficial.
Humans are still evolving-here’s a photo of me from high school. Just kidding…INDIVIDUALS can’t evolve!….but our species is.
Evolution is a theory but some believe it may be the most influential in modern scientific thought because of its very broad implications
Emergence of Evolutionary Thought
Evolution is the process by which SPECIES change over time.
A Theory is a BROAD explanation that has been tested and supported.
Like most theories, evolutionary theory keeps developing and expanding.
Most of Darwin’s ideas remain scientifically supported.
The Emergence of Evolutionary Thought
Early Explanations of life’s diversity
If species were individually and perfectly created at one time and one place
Then….
Why were organisms different in different regions of earth?
Why are current organisms different from ancient organisms?
If each species is different, why are there the same fundamental structures and body plans to do different things in animals?
Charles Darwin 1809-1882
Charles Darwin was the NATURALIST aboard the HMS Beagle. His job was to collect animals and plants for identification and potential commercial value.
The Beagle’s mission was to map the ports of South America. They left in 1831 and returned 5 years later in 1836.
Charles Darwin 1809-1882
Darwin witnessed a tremendous diversity of animal life both living and FOSSILIZED
He traveled to the Galapagos Islands and collected a bunch of different birds, but it turned out they were all FINCHES!
He became convinced that species change over time
Darwin’s Influences
Darwin was influenced by a number of Scientists and their thoughts including:
Jean Baptiste Lamarck
Thomas Malthus
Charles Lyell & James Hutton
Georges Cuvier
Darwin’s Influences: Jean Baptiste Lamarck
Lamarckian Inheritance
Lamarck noticed that each organism is usually well ADAPTED to its environment.
He proposed that organisms change over time as they adapt to changing environments.
Darwin once accepted this idea because it proposed a role for inheritance in evolution.
Larmack thought early Giraffes stretched their necks to feed and they’re newly acquired Long neck was then passed off to offspring….._WRONG___!!!Acquired traits are not hereditable (or are they?)
Lamarckian Inheritance
Some of Lamarcks ideas still have relevance today though and he may be right in a way…check out Epigenetics for an extra credit project!
Darwin’s Influences: Thomas Malthus
Malthus:
“The tragedy of the COMMONS”
Populations tend to grow faster than the food supply needed to feed it
Darwin’s Influences:
Charles Lyell & James Hutton
Lyell & Hutton- GRADUALISM
Changes occur over vast periods of time in geology; land formations move and topography changes
Darwin’s Influences: Georges Cuvier
Cuvier - CATASTROPHISM
Geologic changes occur rapidly and have catastrophic outcomes for living things,
…..like extinction
Darwin’s Theory: DESCENT with Modification
Darwin’s Dangerous Idea:
He didn’t publish his findings until he was 50!
“On the Origin of Species” 1859
Evolutionary pathway resembled a branched tree
NOT a ladder from lower forms to higher forms
All CONTEMPORARY species have descended from earlier species
DESCENT WITH MODIFICATION: Organisms today evolved from previous species as a result of Natural Selection
Darwin’s Observations
Individuals in a population VARY some of these variations are inheritable
Populations produce more OFFSPRING than the environment’s food, space, and other assets.
Therefore, species COMPETE for resources
EVOLUTION BY NATURAL SELECTION
Evolution is a change in the inherited characteristics of a population from one generation to the next.
Darwin’s theory predicts that;
Over time, the number of individuals that carry ADAPTIVE traits will increase in a population.
Every living thing has the potential to produce many offspring, but not all of those offspring are likely to SURVIVE and reproduce.
Individuals that have traits that suit their environment are more likely to survive.
Individuals that have certain traits tend to produce more offspring than others do.
These differences are part of natural selection.
The Mechanism of Natural Selection
Selection and Adaptation
Darwin’s theory explains why living things vary in form and match their environment.
Each ENVIRONMENT presents unique challenges and opportunities to survive and reproduce.
So, each species evolves because of the “selection” of those individuals that survive the challenges or make best use of the opportunities.
The Mechanism of Natural Selection
Put another way, each species becomes adapted to its environment as a result of living in it over time.
An ADAPTATION is an inherited trait that is present in a population because the trait helps individuals survive and reproduce in a given environment.
Darwin’s theory explains evolution as a gradual process of adaptation.
Note that Darwin’s theory refers to populations and species—not individuals—as the units that evolve.
–Also, keep in mind that a species is a group of populations that can INTERBREED
DARWINS THEORY OF EVOLUTION BY NATURAL SELECTION
4 Steps in Darwin’s Theory of Evolution by Natural Selection.
Step 1 Overproduction: Every population is capable of producing more offspring than can possibly survive.
Step 2 Variation: Variation exists within every population. Much of this variation is in the form of inherited traits.
Step 3 Selection: In a given environment, having a particular trait can make individuals more or less likely to survive and have successful offspring. So, some individuals leave more offspring than others do.
Step 4 Adaptation: Over time, those traits that improve survival and reproduction will become more common.
The Mechanism of Natural Selection
VOCABULARY
Natural Selection: greater reproductive success displayed by individuals with favorable traits
Variation: differences within a population
Adaptations: traits that are selected for because they help an organism survive and reproduce
Evidence for Evolution
Evidence for Evolution comes from each of the following disciplines
The Fossil Record
Biogeography
Development Biology or
Embryology
Comparative Anatomy
Biochemistry
Evidence for Evolution
A Fossil is a record of an animal that is preserved in rock
Found in SEDIMENTARY Rock
Fossils show overall structural scheme of how organism evolved
Including:
Body scheme
Feeding behavior
Mobility
Social Structure
New fossils in upper layers, older fossils in lower layers
Evidence for Evolution
Evidence from the fossil record allows us to piece together an Evolutionary SEQUENCE
The Evolutionary Sequence of Modern Cetacea (Whales)
New fossils in upper layers, older fossils in lower layers
Comparative Anatomy
HOMOLGOUS Structure:
Similar structures in related organisms suggests organisms share a common ancestor
Human Hand = Whale flipper
ANALOGOUS Structures
Similar structures in nonrelated organisms show evolution recreates similar solutions to different environmental challenges
Kangaroo vs Deer
Vestigial Organs
VESTIGIAL Organs with no apparent use, but resemble functional structures in ancestors
Tailbones
Wisdom Teeth
Appendix
Whale Pelvis
Comparative Embryology
Ontogeny Recapitulates Phylogeny- Organisms with common descent have similar organs
Embryos undergo many physical and genetic changes as they develop into mature forms.
Scientists compare the EMBRYOLOGICAL development of species to look for similar patterns and structures. Such similarities most likely derive from an ancestor that the species have in common.
For example, at some time during development, all vertebrate embryos have a tail. Vertebrates are animals that have backbones.
Vertebrates breathe though lungs but as embryos, all vertebrates have gills that becomes the Eustachian tube in man
Biochemistry
To explain the patterns of change seen in anatomy, scientists make testable predictions.
For example, if species have changed over time, the GENE that determine their characteristics should also have changed.
Genes can change by mutation and that such change can make new varieties appear.
A comparison of DNA or amino-acid sequences shows that some species are more genetically similar than others.
Chimps –Humans 99% Homology
These comparisons, like those in anatomy, are evidence of hereditary relationships among the species.
Biogeography
Study of species distribution on Galapagos Islands look similar to South American species
Each island would have to had it own special creation event for each species.
Darwin contended one species MIGRATED from South America and underwent Adaptive Radiation
How Do Variations Arise?
Natural selection IS NOT the cause of variation
Mutation - Random changes in DNA sequences in the parents genome
Gene Shuffling - mixing of parental chromosomes can create new genetic combinations
Variation arises randomly. Variations are then SELECTED on by nature.
Variations which are selected for are called ADAPTATIONS
Adaptations and Speciation
Types of Adaptations
STRUCTURAL Adaptations: Involve structure or anatomy - Bird’s beak, Anteaters sticky tongue
PHYSIOLOGICAL Adaptations: Functions in organisms - Poison Venom in a snake, ink of an octopus
BEHAVIORAL Adaptations: Behavior aids in survival and reproduction
Wildebeasts/ Caribou/ Bird MigrationWolves Hunt in Packs Fish swim in schools
Species & Speciation
Species: A group of organisms that are so similar they can interbreed and produce VIABLE/FERTILE offspring
Some Organisms are similar enough to form Hybrids-they can breed but the offspring is infertile
Horses + Donkey = Mule
Lion + Tiger = Liger
…Not the same species but a HYBRID
Human male + human female = human baby…same species!
3 Types of Natural Selection
Directional Selection: Shifts a population toward one extreme form of a trait
Stabilizing Selection:Shifts a population toward intermediate (medium) traits
Disruptive Selection:Extreme phenotypes are more common
DIRECTIONAL Selection
Shifts a population toward one extreme form of a trait
4 million years ago there were heavy cheetahs
Over time, light, fast animals reproduced more successfully
Natural selection favored the genes that pushed the cheetah’s weight in one direction…lighter
Or the Human Brain…it has continued to grow larger with more convolutions (gyrii) over time
STABILIZING Selection:
Shifts a population toward intermediate (medium) traits
Example: Most human babies weight ~ 7pounds
DISRUPTIVE Selection:
Extreme phenotypes are more common
Example: African butterflies appear as either bright orange or bright blue
These colors mimic other butterflies that are foul-tasting; less likely to be eaten
Intermediate butterflies look like neither, and are more likely to be eaten
Patterns of Evolution
SPECIATION-
Organisms which are separated by distance + gene pool will no longer interbreed. Each group becomes new species
Species become dissimilar or more alike over time through gradual Change
5 Types of Evolution
Divergent Evolution:
Adaptive Radiation:
Convergent Evolution:
Coevolution
Extinction
DIVERGENT EVOLUTION:
Single population is split into 2 or more populations.
CONVERGENT EVOLUTION:
2 dissimilar species evolve in ways to make them APPEAR more similar
Sugar Gliders- winged marsupials in Australia
Flying Squirrels - Winged squirrels in Northern Hemisphere
COEVOLUTION
Organisms are part of one other’s environment, so they can affect one another’s evolution. Species that live in close contact often have clear adaptations to one another’s existence.
ADAPTIVE RADIATION
Over time, species may split into two or more lines of descendants, or lineages. The process tends to speed up when a new species enters an environment that contains few other species. (FINCHES)
EXTINCTION
If all members of a lineage die off or simply fail to reproduce, the lineage is said to be extinct. The fossil record shows 99% of all species have become EXTINCT
The Pace of Evolution and Earth History
Gradualism: Over time, new species arise as environment change
If true, we should see intermediate species in fossil record…not always true
Catastrophism: Rapid catastrophic events shape earth and living thing
THE CURRENT ACCEPTED THEORY
PUNCTUATED EQUILIBRIUM:Species exist for long periods of time without changes,
then large changes occur over short periods of time
Populations & Evolution
Larger populations tend to have more genetic variation
Smaller populations tend to have less genetic variation
Genetic Drift/Founder Effect- Loss of genetic variation due small population sizes.
Extinction more likely-10,000 years ago, almost all cheetahs go extinct due to climate changes. Resulting cheetahs have little genetic diversity
BIOLOGYNAME______
BRAINSTORMING
USE THE FOLLOWING DIAGRAM TO COMPARE AND CONTRAST DARWIN AND LAMARCK’S IDEAS CONCERNING CHANGES IN SPECIES