Biology unit 7 test

Eon, Era, Period, Epoch

Paleozoic, Mesozoic, and Cenozoic

• Paleozoic: Age of Ancient Life

• Mesozoic: Age of Reptiles

• Cenozoic: Age of Mammals (current)

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

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

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

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.

4.6 billion years old

• Carbon dioxide

• Water Vapor

• Nitrogen

• Methane

• Ammonia

• WAMNC acronym

• Hot, unstable and extreme weather conditions

Simple: water vapor cooled.

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.

It settled to the bottom of the ocean

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

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

First life:  Heterotrophic, Anaerobic Prokaryotes

Life evolved:  Autotrophic, Anaerobic Prokaryotes

Chemosynthesis: Using chemicals to make food

Ex:  Hot sulfur springs, harsh environments

Life evolved:  Autotrophic, Aerobic Prokaryotes

Photosynthesis: Using light to make food

Definitions:

• Anaerobic: respiration WITHOUT oxygen

• Aerobic: respiration WITH oxygen

• Heterotrophic: organism that cannot produce its own food

• 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.

Eukaryotic cells arose from living communities formed by prokaryotic organisms.

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

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

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.

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

Reproduction and variation.

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

Evolution is neither entirely fixed nor entirely random.

To explain how all species are related to each other.

Species change over time

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

Heredity, overproduction, selection or death, variation

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.

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

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.

variation.

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

very slowly, gradual

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.

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

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

origin from a common ancestor

Factors that prevent organisms from reproducing with each other

• 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

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

• 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.

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

• Different songs (birds)

• Different mating calls (frogs)

• Different scents (smells)

• Habitat Isolation

• Temporal Isolation

• Behavioral Isolation

Sympatric Speciation - living in the same location

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

Organisms will go through a gradual and continuous change

organisms that can interbreed (reproduce) and produce fertile offspring

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

Natural selection

• Directional Selection

• Stabilizing Selection

• Disruptive Selection

Choosing for one extreme, choosing against the opposite extreme.

Choosing for average, choosing against the extremes.

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

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

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.

1. Fossil Evidence

2. Comparative Anatomy

3. Embryology

4. Biochemistry (DNA)

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

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

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

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

Comparative anatomy

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

• Examples

  • Limb Buds

  • Gill Slits

  • Tail

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.

• 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

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.