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Biology 120 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Allopatric Speciation

A

Greek word: allo- other, patra-homeland

gene flow is interrupted when a population is divided into geographical isolated subpopulations

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2
Q

Aristotle

A

Greek philosopher who viewed species as fixed and unchanging. created the ‘scala Naturae’ and concluded that life-forms could be arranged on a ladder of increasing complexity.

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3
Q

sympatric speciation

A

speciation occurs in populations that live in the same geographic area. Caused by polyploidy, habitat differentiation, and sexual selection.

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4
Q

speciation

A

The process by which one species splits into two or more species.

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5
Q

microevolution

A

mechanisms such as mutations, natural selection, genetic drift, and gene flow.

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6
Q

macroevolution

A

origin of new groups or organisms such as mammals or flowering plants through a series of speciation events.

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7
Q

sexual selection

A

females select males based on their appearance.

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8
Q

species

A

a group of populations whose members have the potential to interbreed in natureand produce viable, fertile offspring but do not produce viable fertile offspring with members of other such groups.

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9
Q

gene flow

A

The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes.

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10
Q

prezygotic barriers

A
  1. impeding members of different species from attempting to mate 2. by preventing an attempted mating from being completed successfully 3. by hindering fertilization if mating is completed successfully.
    habitat isolation, temporal isolation, behavioral isolation, gametic isolation and mechanical isolation
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11
Q

Habitat Isolation

A

type of prezygotic barrier. Two species that occupy different habitats within the same area may encounter each other rarely, if at all, even though they are not isolated by obvious physical barriers, such as mountains.
ex: Thamnophis snake

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12
Q

Temporal isolation

A

Type of prezygotic barrier. Species that breed during different times during the day, different seasons, or different years cannot mix their gametes. ex: western and eastern snake.

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13
Q

Behavioral Isolation

A

type of prezygotic barrier. Courtship rituals that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species. Such behavioral rituals enable mate recognition- a way to identify potential mates of the same species. ex: Blue-footed boobies

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14
Q

Mechanical Isolation

A

type of prezygotic barrier. Mating is attempted, but morphological differences prevent its successful completion. ex. two species of snails.

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15
Q

Gametic Isolation

A

Type of prezygotic barrier. Sperm of one species may not be able to fertilize the eggs of another species.Sea Urchins.

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16
Q

Postzygotic barrier

A

reproductive isolation after the hybrid zygote is formed. 1. Developmental errors may reduce survival among hybrid embryos 2. hybrids can be infertile.

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17
Q

Reduced Hybrid viability

A

The genes of different parent species may interact in ways that impair the hybrid’s development or survival in its environment. ex. salamander hybrids

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18
Q

Reduced Hybrid Fertility

A

Postzygotic barrier. The chromosomes of the two parent species differ in number or structure, meiosis in the hybrids may fail to produce normal gametes. ex mule

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19
Q

Hybrid breakdown

A

Postzygotic barrier. Some first generation hybrids are viable and fertile, but when they mate with one another or with either parent species, offspring of the next generation are feeble or sterile. ex:strains of rice.

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20
Q

Evolution

A

Descent with modification. A change in the genetic composition of a population from generation to generation

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21
Q

Uniformitarianism

A

Proposed by Charles Lyell, idea that the same geological processes are operating today as in the past.

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22
Q

J. Lamarck

A

proposed a mechanism for how life changes. the “use and disuse” idea. The idea that body parts that are used extensively become larger and stronger and those that are not deteriorate. Also, “inheritance of acquired characteristics” giraffes got their long necks over many generations of stretching their necks ever higher.

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23
Q

Carlo Linnaeus

A

created the binomial naming of species and grouped similar species into increasingly general categories based on their pattern of creation.

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24
Q

Charles Darwin

A

Coined the ‘decent with modification’ about evolution. Traveled on the Beagle to South America where he studied plants and animals. He noticed an important detail about the Finches in the Galapagos Islands which led to his theory of Natural Selection. Published book “On the Origin of Species by Means of Natural Selection

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25
Natural Selection
a process in which individuals that have certain inherited traits tend to survive and reproduce higher rates than other individuals because of those traits.
26
Charles Lyell
proposed the uniformitarianism theory
27
Artificial Selection
The way humans have modified other species over many generations by selecting and breeding individuals that possess desired traits.
28
Thomas Malthus
Economist who said that much of human suffering - disease, famine, and war- was the inescapable consequence of the human populations potential to increase faster than food supplies and other resources.
29
Adaptive Radiation
periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles, or niches, in their communities.
30
Directional Selection
occurs when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting a population's frequency curve for the phenotypic character in one direction or the other. Moves peak of graph to left or right.
31
Disruptive Selection
occurs when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes. Splits the center peak into two; one on the left and one on the right.
32
Stabilizing Selection
acts against both extreme phenotypes and favors intermediate variants. Just makes the peak taller and skinnier.
33
Fitness
An organisms ability to live long enough to reproduce and pass on its genes.
34
Genetic Drift
When a chance event causes allele frequencies to fluctuate unpredictably form one generation to the next especially in small populations.
35
Founder Effect
When a few individuals become isolated from a larger population and establishes a new population whose gene pool differs from the source population.
36
Bottleneck Effect
In sudden changes in the environment, by chance alone, certain alleles may be overrepresented and some may be absent altogether.
37
Mutation
a change in the nucleotide sequence of an organism's DNA.
38
Pangaea
single large continent of all Earth's land masses about 250 million years ago.
39
Phenotype
The outward representation of inherited traits.
40
Genotype
The actual alleles present in the gene even if they are not phenotypically represented.
41
Analogous
when two species share features because of convergent evolution. resemblance is said to be analogous.
42
Convergent Evolution
The independent evolution of similar features in different lineages.
43
Vestigial Structures
are remnants of features that served a function in the organism's ancestors
44
Homology
Similarity resulting from common ancestry.
45
Mendel
proposed a particulate model of inheritance in which organisms transmit discrete heritable units to their offspring.
46
Recessive
allele that can be masked by a dominant trait. In order to be present in the phenotype both alleles must be recessive.
47
Ernst Mayr
created the biological species concept, he classified species based on reproductive compatibility, if gene flow was possible, and preserved by reproductive isolation.
48
Hardy- Weinberg Principle
Principle states that the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work. This does not take into account: 1. no mutations 2. random mating 3. no natural selection 4. extremely large population size 5. no gene flow P^2+2PQ+Q^2=1 P^2=expected freq.of genotype homo. dom. 2PQ= expected freq. of genotype hetero. Q^2= expected freq. of genotype homo. rec.
49
Eukaryotes
organisms with membrane bound nucleus
50
Prokaryotes
organisms with free nucleus and other organelles.
51
Particulate genes
The mechanism that Mendel hypothesized. That discrete units transfer inheritable genes to offspring.
52
Master Molecule of Life
DNA
53
Levels of Classification
``` King=Kingdom Phillip=Phylum Came=class Over=order from=family Germany=genus souserd= species ```
54
Plato
mentor of Aristotle. believed in Essentialism- everything has a special Creator- fixity of species
55
The Finches of the Galapagos
Darwin collected information on the finches of the islands in the Galapagos. They all had different beaks that Darwin believed was caused by natural selection.
56
Unicellular
Organisms that are made up of a single cell
57
Heterotroph
An organism deriving its nutritional requirements from complex organic substances.
58
Autotrophs
An organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.
59
Geologic Time Scale
Earth's history divided into 3 eons. 1. Archaean 2. Proterozoic 4. Phanerozoic
60
Robert Fitzroy
Captain of the Beagle- the ship that Darwin rode to South America to discover the plants and animals of south america and the finches of the Galapagos Islands.
61
Genetic Recombination
The process of forming new allelic combination in offspring by exchanges between genetic materials (as exchange of DNA sequences between DNA molecules).
62
Gondwana Land
The hypothetical protocontinent of the Southern Hemisphere that, according to the theory of plate tectonics, broke up into India, Australia, Antarctica, Africa, and South America.
63
Laurasia
Hypothetical protocontinent of the northern hemisphere that broke up into europe russia china and north america.
64
Cenozoic
third era on the geological time scale. contains the Quaternary and Tertiary period. The Quaternary period 11,000 years ago Tertiary period started 13.1 million years ago
65
Mesozoic
second era of the geological time scale contains 1. Triassic 2. Jurassic 3. Cretaceous Triassic was 230+10 million years ago Jurassic was 181+ 5 million years ago Cretaceous was 135+5 million years ago
66
Paleozoic
1st era contains 1. cambrian 2. ordovician 3. silurian 4. Devonian 5. Carboniferous 6. Permian Cambrian from 600+5 million years ago Ordovician from 500+10 million years ago Silurian from 425+10 million years ago Devonian from 405+10 million years ago Carboniferous from 345+10 million years ago Permian from 280+10 million years ago

Biology 120 (1 decks)

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