study guide for unit 3

Question 1

what is evolution?

Answer 1

means “change over time”
is the process by which modern organisms have descended from ancient organisms.

Question 2

who is charles darwin?

Answer 2

• known for his contributions to evolutionary biology
• discovered natural selection
• went on trip to make observation and collected evidence to propose his theory of evolution about the way life changes overtime.

Question 3

what was Darwin’s journey on HMS Beagle?

Answer 3

1831 went on this journey. visited 4 continents and collected specimens of a great variety.

Question 4

who is George Curvier?

Answer 4

fossils & catastrophism
collected convincing evidence that the fossilized animals were very different from any living species and that some organisms had become extinct.
- catastrophism: events in the past occurred suddenly and were caused by different mechanisms than those operating today.
- most of his work and research produced knowledge that would help support Darwin’s theory of evolution.

Question 5

Who is James Hutton?

Answer 5

geologic forces
he published a detailed hypothesis about geologic forces that have shaped the earth:
- layers of rocks form slowly
- some rocks are moved up by forces to form mountains
- mountains and valleys are shaped by natural forces like wind and rain
- this happens over millions of years.
his ideas provided frame work for the eons required by the biological evolution he observed in the fossil record.

Question 6

who is Charles Lyell?

Answer 6

uniformitarianism: the same geologic forces that were active in the past are still present today
- Darwin read his book and understood more about geologic forces active on earth
- this new understanding of geology affected Darwin in 2 ways:
1) asked himself a question: if the earth changed slowly over time could the living organisms on earth also change slowly overtime?
2) Darwin realized that in order for life to change over time, the earth would have to be extremely old.

Question 7

who is Jean-Baptiste Lamarck?

Answer 7

theory of acquired characteristics: individuals acquire traits during their lifetime as a result of their experience/behaviour then pass these traits to their offspring.
- one of first scientist to purpose that living organisms had changed over time.
example: if you lose a finger on accident, your child will be missing a finger. This was rejected.

Question 8

who is Thomas Malthus?

Answer 8

human population growth
- published a book that talked about human population growth, had a great impact on Darwin’s developing theories.
- he figured babies are being born faster than people dying; Darwin realized that this applied more strongly to plants and animals.

Question 9

what is descent with modification?

Answer 9

in Darwin’s book he discusses “descent with modification” by using the term, Darwin hypothesized that all organisms were descended from earlier forms.

Question 10

what is selective breeding?

Answer 10

a method of breeding that allows a joy those individual organisms with desired characteristics to produce the next generation.
example: the fasted horses, or trees that grow the best fruit.

Question 11

what is artificial selection?

Answer 11

variations exist in plants and animals. by selective breeding, humans select the variation they find to be most useful.

Question 12

Darwin’s 8 concepts:

Answer 12

1. organisms are like other organisms. stability in process of reproduction.
2. in any given population, there are chance variations among individual organisms. some are passed to future offspring.
3. struggle for existence: members of a species compete for food, water, living space and other resources.
4. number of individuals that survive & reproduce in each generation is small compared to number produce.
5. which individuals will will survive and reproduce and which will not is determined by how well suited an organisms is to its environment. Darwin called it “fitness”
6. individuals with characteristics that are not well suited to their environment either die of leave few offspring.
7. fitness is the result of adaptions and adaptation is any inherited characteristic that increases an organisms chance of survival.
8. individuals w characteristics well suited to their environment survive and reproduce more successfully, passing these favourable traits onto future generations. this became offspring.

Question 13

what is the fossil record?

Answer 13

fossils are a record of the history of life on earth.
- extinct fossils resemble organisms that are living today.
- shows when new groups appeared in earths history and how they changed over time
- the further down the fossil(strata) is the older it is
- fossils provide evidence about the environment in which the organism existed and in how the organism was adapted to that environment

Question 14

what is biogeography?

Answer 14

the study of organisms around the world.
- Darwin concluded that species now living on different continents had each descended from different ancestors, however bc some animals were living under similar ecological conditions on the same continent, were exposed to similar pressures of natural selection bc of this different animals evolved w similar features.

Question 15

how can 2 species that look different be more closely related than 2 other species that look similar to each other?

Answer 15

regardless of their physical appearance, 2 species are more closely related when they share a common ancestor.

Question 16

what is homologous body structures?

Answer 16

body parts that are similar in structure, but have different function.

Question 17

example of homologous structure

Answer 17

human arm, bat wing, dolphin flipper are very similar, they all go shoulder to the finger digits, but get used differently.
they all have the same forelimbs bone structure bc they shared a common ancestor in their distant past. so different populations of descendants adapted to different environments

Question 18

what is embryology?

Answer 18

the study of embryos and their development.
many embryos of organisms of different species look similar in early stages of development
why they look similar? these organisms shared a common ancestor

Question 19

what is biological molecules?

Answer 19

1. scientists observe similarities among organisms at the molecular level
2. all species of life have the same genetic machinery of DNA & RNA
3. all types of green plants have similar types of chlorophyll

Question 20

what is LUCA?

Answer 20

Last Universal Common Ancestor
- a single celled organism that lived between 3-4 billion years ago.

Question 21

how does LUCA lead to all life on earth?

Answer 21

due to the mutations that took place in its DNA, The hypothesized organism from which all life on earth is believed to have descended.

Question 22

what are extinctions?

Answer 22

a. species compete for similar resources, the ones better at acquiring than the competitors win
b. the environment changes… some species adapt while others perish
c. gradual extinctions occur due to natural selection.
d. extinctions are not caused by ordination natural selection but by catastrophic events in earths history.

Question 23

what effects have mass extinctions had on life on earth?

Answer 23

with each disappearance of so many species, many habitats and niches were opened and left unoccupied.
- this provides the ecological opportunity for those organisms that survived the mass extinctions to move into these habitats and niches.

Question 24

what is adaptive radiation?

Answer 24

the sudden appearance of many new species when organisms move into unoccupied habitats and niches
a. evolution of the 1st amphibians as they were first invertebrates to colonize the landmasses
b. the arrivals of dinosaurs
c. explosion of new mammal species that occurred when the dinosaurs became extinct

Question 25

what is convergent evolution?

Answer 25

the process by which species evolve similar traits.
- closely related organisms shared characteristics bc of common descent.
- distantly related organisms can come to resemble one another bc of convergent evolution.
- organisms that are very distantly related.

Question 26

analogous?

Answer 26

same function, different structure
^convergent evolution
butterfly & bat wings

Question 27

homologous?

Answer 27

same structure, different function
^common descent
bar wing and human arm

Question 28

what is divergent evolution?

Answer 28

closely related species, become more and more dissimilar.
- the descendants of a single ancestor diversify into species that each fit different parts of environment.

Question 29

example of divergent evolution?

Answer 29

short neck tortoise (original) because the water and vegetation was all low and on the ground so they could reach.

later on, vegetation started to rise up higher on plants and trees, so the tortoises adapted and began to develop longer necks to help survive.

Question 30

what is coevolution?

Answer 30

the process by which 2 species evolve in response to changes in eachother.
- an evolutionary change in one organisms also be followed by a corresponding change in another organisms.

Question 31

example of coevolution?

Answer 31

natural selection favoured any insect that could withstand the effects of the toxin, those insects that survived and produced a population of offspring.
*this is coevolution since one species evolved in response to another species.

Question 32

what is punctuated equilibrium?

Answer 32

species are in state of equilibrium (not changing much)

punctuated equilibrium is a term used by a pattern of long, stable periods interrupted by brief periods of more rapids change.

Question 33

equilibrium can be upset when:

Answer 33

• small populations become isolated from the main populations
• small groups of organisms migrate to new area
• mass extinctions open up a new ecological niches

Question 34

what is an adaptation?

Answer 34

any inherited characteristic that increases an organisms chance of survival

Question 35

because of biogeography what happened/important?

Answer 35

different animals evolved with similar features.