BIOLOGY CH16 Evolution
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!
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 distibuted today and in the fossil record
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
DIRECTIONAL SELECTION: When a direction in phenotypes is favored- bigger brains
STABILIZING SELECTION: When 1 average phenotype is selected for – 7 lb babys
DISRUPTIVE SELECTION: When 2 extreme phenotypes are selected for simultaneously- different colored butterflies
SPECIATION: The formation of new species through evolution
BIO Chapter 17 Population Genetics and Speciation
MICROEVOLUTION: the study of changes in allele frequency of a population
POPULATION: A group of organism of the same species that are breeding
PHENOTYPIC VARIATION: the allele frequencies within a population
ALLELE FREQUENCY: the ratio of specific alleles in a population
GENETIC VARIATION: the different forms of alleles and traits in a population
HARDY WEINBERG EQUILIBRIUM: IS an IDEAL condition (IMPOSSIBLE) in which no evolution or allele
(EQUILIBRIUM)- when all of the following DO NOT HAPPEN
GENE FLOW: the gain or loss of new alleles through immigration or emmigration
MUTATION: change in DNA sequence
NONRANDOM MATING: reproductive selection, females choose mates selectively
GENETIC DRIFT: small populations can have major changes in allele frequency
NATURAL SELECTION: when the environment favors a particular allele over another
FOUNDER EFFECT: the initial alleles/individuals in a population have great effect on allele frequency
POPULATION SIZE: the larger the population the smaller the impact of individual changes in allele frequency
SPECIATION: the development of new species through directional, disruptive or stabilizing selection
REPRODUCTIVE ISOLATION: a barrier to reproduction amoung individuals that leads to new species
Geography: physical barriers like rivers, canyons, oceans –squirrels in grand canyon
Ecological Niche: organisms are performing different roles in an ecosystem – Darwin Finches
Mating Behavior and Timing: migrations, mating dances in birds
Polyploidy: changes in chromosome number
Hybridization : pairings between similar species- liger
frequency change occurs
Types of Natural Selection and Evolution
Identify the type of natural selection – stabilizing, directional, or disruptive.
1. The peppered moth becomes lighter in color over time. ____________________
2. Giraffe necks become longer. __________________
3. Most human males are between 5’7” and 6’2”. _____________________
4. Poison dart frogs appear as either a bright orange or a bright blue. ____________
5. Whales have become larger in size over time. _________________
6. Shell color of limpets are pure white or dark tan. _______________
7. Most small anoles lizards are between 3 and 6 inches long. _________________
8. Anteaters’ tongues have gotten progressively longer over time. ______________
Identify the pattern of microevolution – mutations, genetic drift, gene flow, random mating,
natural selection
1. By chance, only the red flowers were pollinated by bees, so only red flowers show up
in the next generation.
2. Due to a change in a base in the DNA code, a new color appears in the wings of local
3. Female marine iguanas will only mate with males who bob their heads.
4. When large seeds are available, birds with large beaks survive and reproduce more
often than birds with small beaks.
5. A rabbit with brown fur moves into a region where there are only gray rabbits.
6. Due to a lack of available food, only the small marine iguanas survive and pass on
their genes.
7. The base adenine is replaced with guanine, resulting in a new enzyme that allows the
organism to digest more meat.
8. A storm blows a group of yellow finches into an area where there were only brown
finches previously.
9. The female bird-of-paradise will only mate with the male who dances in a certain way
for her.
10. For unknown reasons, only the black mice mated in the spring, so no white mice were
seen in the following months.
Identify the pattern of macroevolution – coevolution, convergent evolution, or divergent
1. Sharks and porpoises have the same fin formations. __________________
2. Primitive flatworms evolved into jellyfish and parasitic roundworms. ________________
3. Moth-pollinated plants often have spurs or tubes the exact length of a certain moth’s
“tongue.” ________________
4. Birds and bats both have wings for flight. ____________________
5. Primitive algae split into gymnosperms and angiosperms. ________________
6. Songbirds have evolved different beaks for seed-eaters and worm-eaters.
7. 20 species of Honeycreepers in Hawaii have evolved to feed on different diets.
8. Acacias trees have large, hollow thorns in which ants live. On the tips of its leaflets, the
plant makes a substance used by the ants as food. The ants defend the tree from
herbivores by attacking/stinging any animal that even accidentally brushes up against
the plant, and prune off seedlings of any other plants that sprout under “their” tree.