Evolution Notes

Understanding Evolution:

Notes:

Darwin and Wallace described the mechanism for evolution

Darwin developed the idea of natural selection, or survival of the fittest

• Most characteristics of organisms are inherited
• More offspring are produced than are able to survive
• Offspring vary in characteristics

Natural selection can only take place if there is variation. These will be spread through mutations and reproduction

Adaptation is a new trait that helps an organism survive

Divergent evolution is the point of change for two species

Biogeography causes different types of evolution to occur to different organisms

Questions 1-8:

1. c

2. b

3. a

4. d

5. Whichever seeds are capable of growing into plants through the more difficult parts of survival demonstrate natural selection.

6. Because they are similar among completely different species - organisms for that matter

7. A theory means tested multiple times without failure

8. A monkey seems more advanced, because of its human-like characteristics. However, they mouse is just as evolved but in a different way.

Formation of New Species:

A species is a group of individual organisms that interbreed and produce fertile, viable offspring

The closer an organism is in species, the more DNA they will have in common

A hybrid is a cross between two species

Many species can create fertile offspring-hybrids

For species to be made, they need to evolve to the point where they cannot interbreed with any other species successfully 

Allopatric speciation is evolution due to change in location

• Dispersal is a simple movement
• Vicariance is a forced geographical change

Sympatric speciation is evolution in the same location

• Mutation
• Aneuploidity is a change in number of chromosomes
• Polyploid is extra

Reproductive isolation

• Prezygotic barrier
• temporal isolation (breed time)
• Behavioral isolation
• Habitat isolation
• Gametic barrier

Questions 1-8:

1. 2n + 1

2. a

3. b

4. b

5. c

6. c

7. c

8. d

Reconnection and Rates of Speciation:

A hybrid zone is where different species that can interbreed create hybrids

• Reinforcement is when the hybrids move away from each other
• Fusion is when the hybrids become one species
• Stability is when the hybrids continue to be produced

Gradual speciation is when species diverge gradually over time in small steps

Punctuated speciation is when a new species undergoes changes quickly from the parent species

Environment has the most effect on speciation

Questions 3 - 4

3. a

4. c

Population Evolution:

Modern synthesis is how natural selection plays a part in speciation

Microevolution is a change in a population’s genetic structure

Macroevolution is evolutionary changes on a broader scale

Gene pool is the sum of all alleles in a population

Traits

Heredity and Traits Think Quest

1.    Go to the following website: http://learn.genetics.utah.edu/content/begin/traits/

2.    Click on “What is Heredity?”  Summarize what heredity is.

They are the genes from parents that are passed onto their offspring. These genes can be found in the DNA of the first 46 chromosomes we are given. For the child to be healthy, it needs to receive exactly one of each chromosome.

3.    Click on “What is a Trait?”  Summarize what a trait is in your own words.

Traits are notable characteristic of someone, and are passed throughout generations. Physical traits are noticeable, as they deal with appearance, and are inherited. They can also be changed by the environment, like the sun changes hair color. Behavioral traits deal more with instincts, and are most notable in sheepdog, and how well they herd. These traits can be changed, through learning. People can also inherit “disease traits” of their parents. This can be changed, as well, by diet and exercise. Traits that are inherited are either homozygous or heterozygous, which deal with the alleles.  Complex traits are also common, which show a blend of multiple alleles.

4.    Click on “What is a Chromosome?”  Describe the structure of a chromosome.
Chromosomes are made up of DNA, which are wrapped compactly around proteins. Humans have 46, or 23 pairs. This is not the same for all organisms.

5.    Click on “How Do Scientists Read Chromosomes?”  Describe how karyotypes are used.

Size, banding, and centromere position.

6.    Click on “Make A Karyotype.”  Do this activity.  Describe how you knew where to place each chromosome.

Based on their size.

7.    How do scientists predict genetic disorders?

8.    What are telomeres and what is significant about them?

They are the ends of chromosomes, and they help protect them from sticking to each other.

9.    How is genealogy tracked in humans?

Family tree, and telomeres through the blood cells.

10. Look at your own avatar. 

a.     Are the traits you listed for your avatar consistent with what you’ve learned today?  Why or why not? 

b.    Based on what you’ve learned today, do you need to adjust anything about your avatar’s traits or its habitat?  Explain.

c.     Create a genealogy for your avatar going back at least to the grandparents.  Sketch this here or on a separate piece of paper.  Label at least one of the traits on your genealogy.