Hon Biology Hill Chapter 16

Explain the belief that European thinkers and philosophers held about the origin of species in the 14th century.

* every species was created perfectly
* there was no room for change in species
* every species was created at the same time & in one place
* every species has an innate desire for perfection

Explain the observations that debunked the beliefs European philosophers held about the origin of species in the 14th century.

* fossils: if species are perfect, why did they go extinct?
* species in isolated places that were similar to species in other parts of the world, and species living in proximity drastically different from each other
* remnants of organs/useless parts, ex. coccyx: if species are perfect, why do these exist?

Explain George Cuvier’s discoveries and observations.

* proposed the idea that many species that once existed are now extinct! explained w/ catastrophism: catastrophic geological events caused extinctions

Explain Lamarck’s theory of the origin of species.

* environmental pressures force selective use or disuse of organs
* by use/disuse, organisms acquired or lost certain traits **during their lifetime**
* these traits could then be passed onto offspring, leading to change in a species

Give an example of Lamarck’s theory of the origin of species with height.

* “I am 3 ft tall. I want to grow taller to reach cabinets filled with food!”
* “Yay, I am now 3.5 ft tall! Now my children will be born with a new baseline height of 3.5 ft!”

Explain Lyell’s theory about geology.

* theory of uniformity: gradual, everyday geologic processes sculpted Earth’s current landscape over **millions** of years
* Principles of Geology

Explain natural selection.

* individuals of all populations struggle for existence by competing for limited resources/being preyed upon
* some individuals have varying traits that make them better suited for an environment, enhancing fitness
* the individuals w/ beneficial traits reproduce more than the ones who don’t b/c they live longer
* the beneficial trait’s frequency among a population increases

Explain Malthus’ theory about economy and human survival, and how Darwin used it.

* factors like famine and disease limit the size of human populations, causing either competition or innovation for humans to survive
* Darwin applied the idea of “competition for limited resources” to all species, not just humans

Use the example of snakes losing their legs to explain natural selection.

* variety: among a snake population, some have legs and some don’t.
* overproduction: the snakes start to overproduce, and the ratio of legged snakes : non-legged snakes remains the same
* competition: birds start to eat the legged snakes b/c they are slower and cannot hide
* thus, the non-legged snakes live longer
* inheritance: non-legged snakes can avoid being killed for longer and therefore reproduce more than legged snakes
* frequency of non-legged baby snakes increases in the new generation

Use the example of birds who eat seeds, some with large beaks and some with small, to explain natural selection.

* variation: among a seed-eating bird population, some have large beaks and some have small.
* overproduction: the birds start to overproduce, and the ratio of large beaked birds to small beaked birds remains the same
* competition: birds with small beaks have an easier time quickly gobbling up seeds
* thus, small beaks don’t suffer from starvation/malnutrition and live longer
* inheritance: small-beaked birds avoided starvation/disease and can therefore reproduce more than large beaks
* frequency of small-beaked baby birds increases in the new generation

Explain why, as England was going through its industrial revolution, the majority of the peppered moth population changed from white to black.

* England’s ind. rev. caused its trees to go from white → black b/c of the soot!
* white peppered moths have a harder time hiding from predators b/c they don’t blend in!
* this leads to black moths living longer, reproducing more, and passing down the black winged trait to their children with more frequency!

How did fossils provide evidence for evolution?

1) extinct species contradicted the idea that all things were created perfect… if perfect, why die?

2) fossils of old, dead species are extremely similar to some species today, so the old species must have been a predecessor/ancestor that changed

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Explain the process of fossilization.

1. organism dies and is not immediately decomposed
2. layers of sediment start to build up, and minerals from groundwater seep into the cavities & crystallize, forming imprints in sediment
3. under pressure, the sediment hardens into rock with the imprints

Explain why fossils are relatively rare.

Dead organisms usually decompose/are eaten shortly after death. Crystallization or bone preservation is also an infrequent process.

Explain radiometric dating in fossils.

Organisms consume both C12 and C14 in their lifetime. Upon death, C14, an unstable isotope, starts to decay. The older a fossil is, the less C14 it has relative to C12.

If the half life of an element is 10 years, given a 30 year old element sample that is 3 grams, how much did the sample originally weigh?

18 g

If the half life of an element is 5 years, given a new sample that weighs 400 g, how much will it weigh after 20 years?

25 g

Explain the plate tectonics theory.

* Earth’s crust is split into parts
* new crust is formed in vents of magma
* the new crust pushes the other end of the crust into a deep sea vent
* conveyor belt type beat

Compare and contrast morphological convergence and divergence.

* divergence: organisms that evolved from the same ancestor, but became different due to different environmental pressures
* have body parts that look different, but are anatomically similar and are encoded for by the same genes
* have similar embryos
* convergence: organisms that evolved from different ancestors, but became similar due to similar environmental pressures
* have body parts that look similar, but are anatomically different and encoded for by different genes
* have different embryos

Give an example of homologous structures.

* humans and reptiles have similar arm structure: one bone (humerus), two bones (radius+ulna), small bones, digits

Give an example of analogous structures.

* fins in sharks and flippers in dolphins: have extremely different bones/anatomies
* they only look similar b/c they both evolved in water

Explain how vestigial structures provide evidence for evolution, what they are, and provide examples.

* vestigial structure: body part that no longer has a function in an organism
* prove that organisms have changed over time
* ex. coccyx, appendix, wisdom teeth… humans used to need them for a diet that was cellulose heavy

Explain how comparative embryology provides evidence for evolution, what it is, and provide examples.

* comparative embryology: comparing developing organism structures
* prove that different species have a common ancestor
* species have extremely similar embryo structures, or some body parts that are not present as adults
* ex. humans and reptiles?? i think??

Explain how biochemical evidence provides evidence for evolution, what it is, and provide examples.

* biochemical evidence: examination of the genes/amino acids of organisms
* similarities in nucleotide/amino acid sequences are observed between species
* can be used to determine how related a species are: Two species with a distant evolutionary relationship have few similarities because many mutations have accumulated in the DNA of their separate lineages.
* ex. Hox genes: a homeotic gene that humans share with fruit flies, proving that we have a common ancestor!

How does plate tectonics drive evolution?

* When two continents collided into one, they brought together organisms, and they physically separated organisms living in an ocean.
* creates new environmental pressures

Explain banded iron in rock formations.

* early iron was all in a reduced form
* iron went into the sea!@!@
* iron isn’t water soluble, so it becomes deposited on the ocean floor
* iron is oxidized by oxygen gas
* boom, banded, oxidized, red iron rocks!!!