Look at the Star-Nosed Mole. (P. 285)

Name______

Per_____

Evolution Notes

Part 1: Principles of Evolution—Evolution by Natural Selection

(Ch. 10 Sec. 1-5, Ch. 12 Sec. 1 & 2)

· Look at the star-nosed mole. (p. 285)

1. What sorts of modifications are obvious?

2. How might these traits arise in the first place?

These ______will then be passed on to future generations.

What is Evolution? (Ch. 10.1-10.2)

Evolution

• Evolution is ______.

• Process of biological change by which descendants come to differ from their ancestors (p.286)

• Change happens in characteristics of a population from one generation to the next

• ______evolve, ______do not!

Vocabulary

• ______-all of the individuals of a species that live in an area (p. 294)

• ______- the differences in the physical traits of an individual from those traits of other individuals in the population p. 290

• ______- group of organisms that are closely related and can mate to produce fertile offspring

– Dogs (Canis familiaris) are all the same species; just like all modern humans are all Homo sapiens

– We have different dog breeds based on their genetic variations but they are all the SAME species. No two people look exactly alike due to genetic variation within the human population.

• ______- process in which new species are formed over time

• ______-a feature that allows an organism to better survive and reproduce in its environment; this can lead to genetic change in a population over time

Charles Darwin- the father of evolution p. 290-291

• born in 1809, in England

• was asked to sail on the ______ to chart stretches of the South American coast

• voyage of H.M.S. Beagle

– 5 year unpaid voyage

– Darwin studied plants, animals, collected fossils (ship’s naturalist)

– found fossils of extinct animals that were similar to modern species

– during his voyage, he made observations that led him to his theory of evolution

– on the ______in the Pacific Ocean he noticed variations among plants and animals of the same general type as those in South America

– Darwin noticed there were several types of ______on these islands, and that they all looked like a bird he had seen on the South American continent

· the most distinct difference among finch species is their beaks

· Why would beaks be different in different locations on an island?

______

· Darwin hypothesized that some of the birds from South America migrated to the Galapagos Islands

· once on the islands, the birds must have ______over the years, explaining the numerous species of birds present

• After returning from the Galapagos and studying all the different types of plants & animals he collected during the voyage, Darwin concluded that organisms change over time….

– He called this ______which means change in species over time.

– Darwin called the mechanism for evolution natural selection (a.k.a. ______).

How Does Evolution Happen?

• natural selection

• mutations

• artificial selection

• geographic separation/ isolation

• genetic drift

• gene flow (migration)

Natural Selection—the main mechanism of evolution (Ch. 10.3 & 11.2)

Natural selection explains how evolution can occur.

• ______a mechanism by which individuals that are better fit for their environment have a greater chance to survive and mate/reproduce p. 293

– aka- survival of the fittest

– What does it mean to be “fit”?

• fit means they have inherited beneficial ______which allow them to be more likely to survive and reproduce more offspring.

– The genetic traits of “fit” individuals become ______common or frequent over time.

– the genetic traits of less fit individuals become ______common or frequent over time.

• There are four main principles to the theory of natural selection

1. Variation—heritable ______that exist in populations

2. Overproduction— ______all offspring will ______due to competition

3. Adaptation—certain variations can allow an individual to survive better than others (the environment can present challenges for survival)

4. Descent with Modification—the number of individuals with the advantageous adaptations will ______over each generation

· A well studied example of natural selection in jaguars is shown in Figure 3.2 p.295

o View animated biology—10.3 Principles of Natural Selection (jaguar)

· Example: Natural Selection and beetles

– beetles have genetic variation

• some are brown, others are green

– there is a struggle for survival

• predation

– more fit individuals leave more ______

– characteristics of fit individuals increase in a population over time

Natural Selection acts on existing variation.

· Natural selection can only act on ______that already exist.

· Natural selection acts on ______; new alleles occur by genetic ______.

o Read p. 296-297 about the 2 examples supporting this concept.

o View Animated Biology 10.3 Natural Selection (fish)

Artificial Selection p. 292

Artificial selection- the process by which ______change a species by breeding it for certain traits

· Humans determine which traits are ______and breed individuals that show those traits.

· Ex. Race horses, show dogs

Part 2: Evidence of Evolution (Ch. 10.4-10.5, Ch. 12.1)

Evidence to Support Evolution

· fossil record p. 298, 306, 348

· biogeography p. 298-9

· homologies : anatomy, development & molecular p. 299-304

Fossil Record (Ch. 10.4 & 12.1)

What is a fossil?

· Fossil—trace of a ______.

· Scientists consider three things about fossils: age, location, and what the environment was like when that organism was alive.

· Fossils are dated through ______dating and ______dating.

· Radiometric dating uses the known time of natural decay of unstable isotopes to calculate the ______of the material.

· Relative dating estimates the age of fossils by comparing the fossils found in certain rock layers to those in other layers. The ______fossils are found on the ______, further from the surface. The ______fossils are closest to the ______.

Fossils can form in several ways (p. 298, 306, & 348). The most common fossils result from permineralization.

What may happen if the organism doesn’t die in ______?

· Fossil doesn’t form; ______takes place

Why is the fossil record not complete?

· Most living things do not form into fossils when they die since the ______are not conducive to fossil formation

· Many fossils may ______have been discovered yet

Biogeography p. 299

• biogeography- is the study of the ______distribution of plants, animals and fossils.

– it is used to test predictions about the nature, age, and location of certain fossils

– species tend to be more ______related to other species from the same area than to other species with the same way of life but living in different areas

Anatomy and Development p. 299-304

homologous structures p. 302

• homologous structures:

– common ancestor

– similar structure

– different function

• example: the bones of a cat, human, whale and bat are ______in structure (made of bones) but have ______functions.

analogous structures p. 303

• analogous structures:

– not related

– ______structures

– ______function

• examples:

– bird wing and insect wing

– quills on a sea urchin, hedgehog and cactus

vestigial structures p. 304

• vestigial structures- serve _____ useful purpose.

• examples:

– pelvic bone in a whale

– human appendix

– pelvic bone & hind limb bones in some snakes

– human canine teeth & wisdom teeth

Embryology p. 299-301

• Embryology--similarities in embryological development among organisms is further evidence of shared ______

• Ex. Embryos of vertebrates

• Ex. Crab and barnacle—adults look very different but the larva can look very similar Fig. 4.4

Molecular Evidence p. 307

· Very different species have similar molecular (DNA, genes, amino acids) and genetic mechanisms. Because all living things have DNA (bacteria, plants, animals, etc.), they share the same ______and make most of the same proteins from the same _____ amino acids.

· More similarities in ______(which translates into proteins) between two organisms, the more ______related they are; the more differences, the more ______related.

Comparing Amino Acids

1. Which organism is most closely related to the human? Why?

2. Which organism is least closely related to the human? Why?

· Remember, the ______sequence dictates the ______sequence through the processes of transcription and translation; therefore, ALL 4 levels (DNA, RNA, amino acids, and proteins) can show evidence of evolution

· Watch Hox genes video clip (2:44)

Section 10.5 “Evolutionary Biology 1”

Part 3: The Evolution of Populations (Ch. 11)

Genetic Variation Within Populations p. 316-321

Vocabulary

· ______combined alleles of all the individuals in a population

· ______different forms of a gene

o flower color gene may be “P” (purple) or “p” (white)

· ______how often something occurs over time

o Allele frequency- measure of how common a certain allele is in the population; decimal value similar to a percent. Ex. if 25 rabbits are white out of a population of 100 rabbits, the frequency of white rabbits is 0.25

Genetic variation in a population increases the chance that some individuals will survive.

Genetic variation comes from two main sources.

· ______- random change in the DNA of a gene; if the change occurs in the DNA of a reproductive cell (gamete=egg or sperm), then the mutation will be passed on to offspring.

· ______- new allele combinations in an offspring that occurred during meiosis through crossing over and independent assortment.

Other Mechanisms of Evolution p. 323-327

Natural selection isn’t the only mechanism through which populations evolve. Other mechanisms include: genetic flow, genetic drift, mutation and sexual selection.

Gene Flow

gene flow – movement of alleles from one population to another

• another word for gene flow is (immigration & emigration)

• gene flow ______the genetic ______of the receiving population

• lack of gene flow between two populations may lead to the formation of different species

Genetic Drift

• genetic drift - change in allele (gene) frequency due to chance; results in loss of diversity

• Two types of genetic drift

1. Bottleneck Effect

2. Founder Effect

o bottleneck effect- when a population is drastically decreased due to a natural disaster (hurricane, disease)

· some genes are completely lost; others are over-represented

· some genes are reduced so much they can’t “make a comeback” in their new population

o founder effect – when a small group ______from a larger population and starts their own population isolated from the original population

· Amish in America – original population was 14 individuals that immigrated from Europe

Mutations

• a random mutation can happen to one individual in a population and can be beneficial, harmful, or ______

• random mutations can increase chances of survival and reproduction

• random mutations can ______chances of survival

– if an individual ______before it can reproduce that mutation is not passed down to the another generation

• random mutations might ______affect an individual’s ability to survive and reproduce and will become a ______instead of a mutation

Ex. dark spots on pigs

Sexual Selection p. 326

· Sexual selection occurs when certain traits ______mating success.

· Ex. Males compete for females such as the head-butting of bighorn sheep; Male peacocks fan out their tails to attract the female.

Hardy-Weinberg p. 328

• 1908 - two scientists created an ______to test these ideas of probability and chance

• Hardy-Weinberg principle- the frequency of alleles in a population does ______change unless evolutionary forces act on the population

• Characteristics of a Hardy-Weinberg (non-evolving) population:

– very large population

– no migration (no immigration or emigration)

– no mutations

– random mating (no individuals are “more fit”, they all seem the same)

– no natural selection

• A population with all of these criteria is ______evolving. This doesn’t happen in nature; therefore ______populations in nature are evolving.

Isolation of a population can lead to speciation p. 332

Reproductive Isolation

· Reproductive isolation – when members of ______populations of the same ______can no longer ______successfully.

· Reproductive isolation can lead to ______.

· Three barriers that can cause reproductive isolation to occur:

1. Behavioral barriers—courtship or mating behaviors are now different in the populations

2. Geographical barriers—physical ______of the populations; Ex. Mountains, roads, rivers

3. Temporal barriers—the two populations aren’t ready to mate at the ______time of day (ex. Flowers that bloom in morning vs. evening) or in the same season

Patterns of Evolution p. 335-341

Convergent evolution- (word part: co-together) individuals share similarities because they are related but because they need certain adaptations to survive in their environment; therefore, they have______structures

Example:

• sharks, dolphins, tuna, & penguins have streamlined bodies, and fins

• HOWEVER sharks are cartilaginous fish, dolphins are mammals, tuna are bony fish, and penguins are birds

• they share similarities because they all ______to the same marine environment and predatory lifestyle

Convergent evolution is sometimes called ______.

Divergent evolution- (word part di – two); the process by which one species begins to split into ______distinct groups with different traits; therefore, they have ______structures

Example:

• all canines have long legs, walk on their toes, non-retractable claws, and dew claws because they all come from a common ancestor.

• different populations diverged at different points and created all these species (domestic dogs, wolves, coyotes, foxes, etc)

Divergent evolution is sometimes called ______and may lead to speciation.

Phylogenetic (or Phylogenic) Tree