Biology unit 7 test

Evolution

What are the four major categories of geologic time (from largest to smallest)?

Eon, Era, Period, Epoch

What are the 3 eras?

Paleozoic, Mesozoic, and Cenozoic

What age are each of the eras?

* Paleozoic: Age of Ancient Life
* Mesozoic: Age of Reptiles
* Cenozoic: Age of Mammals (current)

How many extinctions have there been so far? (that we were taught to care about for this unit, ignore the extra mass extinctions)

3

What is relative age?

Geologists use the Law of Superposition and Index Fossils to determine an approximate age of a sample.

What is the law of superposition?

The Law of Superposition states that younger rocks are located in layers above older rocks.

What are index fossils?

A fossil of characteristic rock and a known age that can be used to determine the relative age of other fossils

What is absolute age?

Geologists use radioactive dating to measure the absolute age of a sample. Half life, the unit of measure compares radioactive to non radioactive elements in a sample. Carbon dating is a type of radioactive dating.

How old is the Earth?

4\.6 billion years old

What did the Earth’s early atmosphere include and what was it like?

* Carbon dioxide
* Water Vapor
* Nitrogen
* Methane
* Ammonia
* WAMNC acronym
* Hot, unstable and extreme weather conditions

How were the oceans formed?

Simple: water vapor cooled.

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Complex: After about 2.0 billion years, the earth began to cool allowing the oceans to form. A large amount of carbon dioxide settled in the ocean and created places for life to thrive. This is when the first prokaryotes emerged.

When the oceans cooled, what happened to much of the atmospheric carbon dioxide?

It settled to the bottom of the ocean

What was the purpose of Miller and Urey’s experiment?

The purpose of the experiment was to see if the ingredients in the early Earth could make the organic compounds necessary for life.

What did their experiment conclude?

It showed that the organic compounds necessary for life could have arisen from the ingredients present on an early earth.

What was life like, and how did it evolve?

First life:  Heterotrophic, Anaerobic Prokaryotes

Life evolved:  Autotrophic, Anaerobic Prokaryotes

     **Chemo**synthesis: Using chemicals to make food 

  Ex:  Hot sulfur springs, harsh environments

Life evolved:  Autotrophic, Aerobic Prokaryotes

     **Photo**synthesis: Using light to make food

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Definitions:

* Anaerobic: respiration WITHOUT oxygen
* Aerobic: respiration WITH oxygen
* Heterotrophic: organism that cannot produce its own food

More in-depth explanation of the previous card

* The first organisms were thought to be __heterotrophic__ prokaryotes that were  __anaerobic__  because there was no oxygen present in earth’s atmosphere.
* Then came the __autotrophic__ prokaryotes similar to present-day archaebacteria. These prokaryotes live in harsh conditions with little sunlight and oxygen such as hot sulfur springs. \*\*This type of food synthesis is known as **CHEMOSYNTHESIS.** 
* Next, came the __aerobic__ autotrophic prokaryotes.  This began to change our atmosphere and allowed for the evolution of organisms that could __aerobically__ respire.  According to the fossil record, the “ oxygen revolution” occurred about 2.8 billion years ago. \*\*This type of food synthesis is known as **PHOTOSYNTHESIS.**

What is the Endosymbiotic theory?

Eukaryotic cells arose from living communities formed by prokaryotic organisms.

Why must multicellular organisms sexually reproduce?

Multicellular organisms are more complex than single-celled organisms and need to increase the probability that favorable genes will be passed on.

What are the advantages of reproducing sexually?

The advantage of sexually reproducing is that it increases genetic variability.

Charles Darwin

Came up with the theory of evolution, published Origin of Species. He came up with his theory because he visited the Galapagos Islands, and noticed similar species of birds that were adapted to their individual islands.

What is natural selection?

When nature (the natural environment) selects which organisms survive long enough to reproduce.

what are the two key ingredients to natural selection?

Reproduction and variation.

What does “the fittest” mean in an evolutionary sense?

The most reproductively successful (has the most offspring that live)

Is evolution random?

Evolution is neither entirely fixed nor entirely random.

what is the goal of the “tree of life”?

To explain how all species are related to each other.

What did Darwin’s theory of evolution attempt to explain?

Species change over time

What did Darwin believe?

Darwin believed that all forms of life descended from a common ancestor.

four components of natural selection

Heredity, overproduction, selection or death, variation

In the 19th century, in London, a pale peppered moth was more common than the black moth. As the industrial revolution took place and soot covered buildings and trees, the black moth became more common. Why did this happen?

Because the soot from the factories made the tree trunks darker, meaning that the lighter moths could be seen more easily and the darker ones were now harder to find.

Lamarck suspected that animals “improved” themselves. What did he believe that a giraffe’s long neck was the result of?

The giraffe stretching to reach food higher off the ground. Lamarck also believed these “acquired” traits were passed onto the next generation.

Darwin, on the other hand, believed in Descent with Modification. What is Descent with Modification?

Populations change as characteristics that allow individuals to survive are selected for. He also believed that the traits of the parents were passed on to their offspring without being modified by the parents.

Darwin realized the importance of the fact that, in any population of living organisms, there already exists ____ in any given characteristic.

variation.

According to Darwin, what does fitness mean?

the ability of an individual to survive and to pass on its characteristics to the next generation.

Darwin proposed that the changes within a species occurred ___ through a ___ process.

very slowly, gradual

How do new species arise?

As needs, adaptations and differences within a species increases, the organisms become more different from each other.

Once a connecting species (the average) disappears, the species are too different and they cannot interbreed to produce a fertile offspring anymore.

Adaptive radiation

the diversification of a group of organisms into forms filling different ecological niches.

Convergent Evolution

the process by which unrelated organisms evolve similarly to live in a similar environment

Divergent Evolution

origin from a common ancestor

Reproductive Isolation

Factors that prevent organisms from reproducing with each other

Geographic isolation

* Also known as allopatric speciation
* When a geographic barrier separates a group of species.
* As time passes, the environment may require different traits and the 2 populations become genetically different __**AND**__ cannot reproduce

Habitat isolation

When organisms in the same general area adapt to different habitats. Ex: a snake that lives in the water vs a snake that lives on land

Temporal isolation

* Time-based isolation when individuals reproduce at different times.
* This is more common for organisms that mate during specific times of the day or year.

Behavioral Isolation

if 2 populations have different courtship behaviors, they will not be able to interbreed.

* Different songs (birds)
* Different mating calls (frogs)
* Different scents (smells)

Which isolations are known as sympatric speciation?

* Habitat Isolation
* Temporal Isolation
* Behavioral Isolation

Sympatric Speciation - living in the same location

Punctuated Equilibrium

Organisms go through fast periods of change, followed by long periods of no change

Gradualism

Organisms will go through a gradual and continuous change

Species

organisms that can interbreed (reproduce) and produce fertile offspring

Population

A group of the same species, living in the same area, that interbreed

What contributes to the shift of traits within a population?

Natural selection

What are the the 3 ways natural selection can affect the distribution of trait phenotypes in a population?

* Directional Selection
* Stabilizing Selection
* Disruptive Selection

Directional selection

Choosing for one extreme, choosing against the opposite extreme.

Stabilizing selection

Choosing for average, choosing against the extremes.

Disruptive selection

Choosing for the extremes, choosing against the average. Can eventually cause two different species since there is no connecting species connecting the two extremes.

Genetic drift

a random change in the frequency of an allele. It is the opposite of natural selection.

Conditions needed for Hardy Weinberg equations

1. The __**population**__ **must be** __**large**__ so that no genetic drifts can affect the population
2. __**Random**__ __**mating**__ **must** __**occur**__ so each individual has an equal chance of passing a trait.
3. __**No**__ __**selection**__ **of** __**traits**__ can occur.
4. __**No**__ __**mutations**__ must occur within the population.
5. __**No**__ __**migration**__ in and out of an area can occur.

What are the 4 categories of evidence?

1. Fossil Evidence
2. Comparative Anatomy
3. Embryology
4. Biochemistry (DNA)

Fossil evidence

The most common method of fossilization is petrification

When an organism dies, it is buried under
many layers of sediment and sand.

Water seeps into the bones, replacing the bone
material with minerals.

Over time, all of the bone is replaced with minerals and eventually becomes rock.

Other methods for preservation are: ice, tar and amber

Homologous structures

Similar in form/location, but different in function. Evidence of divergent evolution. Origin from a common ancestor

Analogous structures

Similar in function but different in structure. Evidence of convergent evolution. Similarities in body due to environment not a common ancestor

Vestigial structures

Organs remaining or surviving in an organism that are no longer used in the same way as previous generations. Evidence suggests that populations have changed over time.

Human Examples: wisdom teeth, tail bone, appendix

The previous 3 cards have been what type of evidence of evolution.

Comparative anatomy

Embryology

Studying developmental stages gives some clue to evolutionary relationships. General characteristics form before developing into specific traits

* Examples
* Limb Buds
* Gill Slits
* Tail 

Biochemistry/ DNA Evidence

The more similar the DNA (or amino acids in a protein), the more closely related the organisms. EX: the matching sequence LYS-GLU-HIS-ISO between a human and a chimpanzee.

Endogenous Retroviruses

* Virus infects egg/sperm cell


* Viral DNA passed onto offspring


* Viral DNA is passed on to many generations 


* Can link similar species with the same viral DNA sequences to a common ancestor
* Ex: Chromosome comparison shows 100’s of similarities in the placement of viral DNA of chimpanzee and human chromosomes, suggesting a common ancestor

how the lab that we did in this unit show Darwin’s principles: Mechanisms of Evolution (with the beans)

it showed how an organism needs food to survive, and when others fall behind in terms of food, the gene that is allowing an organism to survive and get more food gets passed on, allowing for the gene to better itself and for that to get passed down too.