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34 Cards in this Set
- Front
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Describe evidence for evolution for 1. Direct evidence |
Guppie experiment:
One areas predators are pikeciclids- prey on colorful big males. So gupies grow dull colored and small. 2nd area predators are killifish- prey on small guppies. So guppies grow very fast and colorful. If a new predator is introduced to a different habitat the guppies will change for their environment to protect against predators. |
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Describe evidence for evolution include 2. Fossil record |
1. Any evidence of an organism from more than 10,000 years ago 2. Provide a collection of ancient remains and allow researchers to test predictions about evolution. |
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Describe evidence for evolution and include 3. Biogeography |
1. Study of distribution of species across the planet 2. The theory of plate tectonics explaining earth shifting continents. 3. Species distributions reveal evolutionary event 4. Wallace's line 5. Island biogeography |
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Describe evidence for evolution and include 4. Anatomical |
1. Homologous structures -have a shared evolutionary origin ex. Limbs in all mammals 2. Vestigial structures -have lost their functions ex. Acestrial whale limb 3. Convergent evolution -produce superficial similarities ie bird's wings and butterfly wings |
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Describe evidence for evolution and include 5. Embryological |
1. Closely related organisms go through similar stages in their embryonic development ex. Chimpanzees and humans. Ex. Similarities between fish, mice, and alligator embryos 2. Homeotic - any gene when mutated leads to new organisms with structures and abnormal or unusual places |
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Describe evidence for evolution and include 6. Molecular |
? 1. Comparing DNA and protein sequences may reveal close relationships 2. The greater the similarities between two modern species, the closer their evolutionary relationship |
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What is convergent evolution? |
The evolution of similar adaptations in organisms that do not share the same evolutionary lineage
Ex. Cacti from Mexico and different from Africa |
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What is the difference between homologous structures and analogous structures? |
Homologous -strucctures share evolutionary origin analogous- independently evolved structures |
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What are homologous structures? |
1. Have a shared evolutionary origin - two structures that are similar and share a common ancestry, but may not have the same function - organization of vertebrate skeletons illustrate homology |
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What are analogus structures? |
1. Structures that evolved independently - the product of convergent evolution ex. Wing of a bird and wing of insect |
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14) define the biological species concept. |
1. Defined by biologist Ernst Mayr 2. A population, or group of populations, whose members can interbreed and produce fertile offspring |
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What prevents species from Interbreeding? |
There are prezygotic barriers and postzygotic barriers |
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Define prezygotic reproductive mechanism. |
Affect the ability of two species to combine gametes and form a zygote |
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What are the prezygotic mechanism? |
1. Ecological / habitat isolation 2. Temporal isolation 3. Behavioral isolation 4. Mechanical isolation 5. Gametic isolation |
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Give an example of ecological / habitat isolation. |
A difference in habitat preference can separate two populations in the same geographic area. Ex. One species of lady bird beetles eat one type of plant, while a closely related species is a different plant. the two species never occur on the same host plant, although they interbreed freely in the laboratory. |
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Define and give an example of temporal isolation. |
Two species of their habitat will not mate if they're active at different times of the day or reach reproductive maturity at different times of the year.
Ex. Among field crickets in Virginia, one species takes much longer to develop than the other, so the adult of the two species may not meet until late in the season, if it all. |
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Give an example and define behavioral isolation. |
Behavioral differences may prevent too closely related species from mating Ex. The mail of two species of tree frogs use distinct calls to attract females. Female frogs choose males of their own species based on the unique calls |
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Give an example and define mechanical isolation. |
When male and female reproductive organs do not match up/ work together to make offspring.
Ex. All the two species of sage plant in California can interbreed, in practice they really do because they use different polinators |
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Give an example and define gametic isolation. |
If a sperm cannot fertilize an egg cell, then no reproduction will occur Ex. Many marine organisms, such as sea urchins, simply release sperm and egg cells into the water. Most molecules enable an egg to recognize the sperm of the same species. In the absence of a match, fertilization will not occur, and the gene pools remain separate. |
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define postzygotic reproductive mechanisms. |
Many keep the species separate by selecting against the hybrid offspring, effectively preventing genetic exchange between the population. - also called hybrid incompatibility. |
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What are postzygotic reproductive isolation mechanisms? |
1. Hybrid inviability 2. Hybrid infertility 3. Hybrid breakdown |
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Define and give an example of hybrid inviability. |
A hybrid embryo may die before reaching reproductive maturity, typically because the genes of his parents are incompatible. Ex. Two species of eucalyptus trees coexist in California florist, but hybrid offspring are rare. |
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Define and give an example of hybrid infertility. |
Some hybrids are infertile Ex. The mule, a hybrid offspring of female horse and a male donkey. Mules are infertile because of Horses eggs has one more chromosome then a donkey sperm cell. meiosis does not occur in the meals themselves because the chromosomes are not homologous |
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Define and give an example of hybrid breakdown. |
Some species produce hybrid offspring that are fertile. However, when the high ridge reproduce their offspring may have abnormalities that reduce their fitness Ex. Some second-generation hybrid offspring of the mosquito species have abnormal genitalia that make meeting difficult. |
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Define allopatric speciation. |
A geographic barrier physically separate the population into two groups that cannot interbreed. - no contact between populations
ex. These barriers maybe rivers, deserts, or anything that divides a habitat. |
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Define sympatric specialization. |
Populations diverge genetically while living in the same physical area. - continuous contact between populations Ex. Fishes called chichlids have diversified into many species within the same Lakes of Africa. |
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What is the difference between allopatric speciation and sympatric speciation? |
Allopatric - two separate regions sympatric - same region |
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Describe adaptive radiation. |
In which of population inhabiting a patchy or heterogeneous environment gives rise to multiple specialized forms in a relatively short time. 1. Speciation typically occurs in response to the availability of new resources (especially common in island groups). 2. some members of a population may inherit the key adaptations that gives them an advantage. 3. some members of a population have a combination of adaptations that enable them to survive a major environmental change. |
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Confusion happened, where separate species can become one? |
? |
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What is a clade? |
Is a group of organisms consisting of a common ancestor and all of its descendants. - a group of species united by a single evolutionary pathway |
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What is a cladogram? |
A tree like diagram built using shared derived characteristics. - emphasis is on historical relationships, evolutionary history. |
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What is punctuated equilibrium? |
Used to describe relatively brief bursts of rapid evolution interrupting long periods of little change. |
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What is gradualism? |
Hello that evolution proceeds in small, incremental changes over many generations |
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What is the difference between punctuated equilibrium and gradualism? |
Punctuated equilibrium - brief bursts of rapid evolution gradualism - small, incremental burst of slow evolution |
