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105 Cards in this Set
- Front
- Back
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What are vestigial traits?
Give an example |
Similarities between functional traits in one organism and nonfunctional features in another
Primates have useful tails. Humans have tails, but they are no longer useful to us, and they are much smaller. |
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What are analogous structures?
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Structures that are similar in function and/or appearance but have derived separately from different ancestors
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Homology can also occur in development. What does this mean?
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Early embryos look very similar, even for animals that look very different as adults
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Describe Homology in Biochemistry. What does this examine?
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This examines the relatedness of sequences of DNA to see how closely related organisms are to each other.
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What is biogeography?
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Pattern of distribution of species on the continents
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Related to biogeography is convergence. What is convergent evolution?
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The development of similar adaptations to a common environmental problem in distantly related species
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What are hominins?
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Humans and human ancestors
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What is the missing link in evolution?
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A common ancestor of humans and chimpanzees
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What does radiometric dating use?
What is it based on? |
It uses the decay of radioactive elements in the fossil to determine age
It is based on the half-life |
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The oldest rocks found to date place Earth at how old?
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4.5 billion years
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How does science reject the transformation model of evolution?
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The evidence of relationships among organisms abound.
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How does science reject the static model of evolution?
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Earth is older than 10,000 years, and species have clearly changed over time.
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How does science reject the separate types model of evolution?
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Universality of DNA, genetic code, and cell components are evidence of a single origin of all life.
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What four observations is natural selection based on?
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Overproduction
Variation Competition Differential Reproduction |
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What is overproduction?
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Every species products more offspring than the environmental resources can support
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What is variation?
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The offspring in a species differ
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What is competition?
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among individuals is most fierce between members of the same species
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What is differential reproduction?
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Different members of the same species produce different numbers of offspring
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Is the subset of individuals that survive long enough to reproduce an arbitrary group?
Why or why not? |
No.
Some variants in a population have a higher likelihood of survival and reproduction than other variants do, thus producing more offspring |
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What is fitness?
How is it defined? |
Fitness is the relative survival and reproduction of one variants compared to others in the same population
It is defined by the amt of your genes present in future generations |
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What are traits that increase an individual's fitness in a particular environment?
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Adaptations
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Is selection a passive or active process?
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Passive
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Natural selection results in the survival of individuals who are best suited for what?
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for the current environment given the current variants in the population
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Survivors are not "fittest" in the absolute sense, only......
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relative to the situation
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Natural selection "selects" for what?
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Adaptive characteristics
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Individuals with high fitness....
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reproduce more often
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Through natural selection, over time, the favorable adaptations become _______ _______ and the unfavorable characteristics....
What is this an example of? |
The favorable adaptations become more common and the unfavorable characteristics tend to be lost
This is an example of evolution |
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What is artificial selection?
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Humans choose the characteristics that are favorable
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What are some examples of artificial selection?
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Fruits & vegetables
dog breeds |
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Natural selection is the result of what?
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Environmental conditions and pressures
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Artificial selection is the result of what?
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Selective breeding
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How did Darwin define sexual selection?
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the advantage which certain individuals have over others of the same sex and species, in exclusive relation to reproduction
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How does sexual selection work from the male perspective?
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Males directly and/or indirectly compete for access to mates
Winners mate w/females and losers do not Winner's genes are passed on to next generation |
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How does sexual selection work from the female perspective?
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Females selectively mate with male that possesses some attractive trait that is often associated with health,strength or some assessment of quality -- how they'd be as a partner and/or father
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What is the handicap principle of sexual selection?
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Advantage of male in sexual selection can put him at a disadvantage b/c he is more easily spotted by predators
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What is a runaway selection?
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It is part of sexual selection
They are exaggerated traits that have a physical disadvantage to possessor yet persist in the population b/c members of the opposite sex find it desirable |
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Define gene pool
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all the alleles from all the individuals in a species
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Define gene flow
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the spread of an allele through a species' gene pool (from parents to offspring)
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Does gene flow occur between different species?
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NO
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Define reproductive isolation
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if two organisms of different species try to mate, no fertile offspring will be produced
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How many species concepts currently exist?
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At least 20
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What is the book definition of a species?
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a group of individuals that can freely interbreed
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What is Dr. Jellen's definition of a species?
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A group whose members are descended from a common ancestor and who all possess a combo of certain defining traits
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What is the morphological species concept?
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a group of individuals that have some reliable physical characteristics distinguishing them from all other species
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What is the evolutionary species concept?
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each independent evolutionary lineage is a species
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What is the phylogenetic species concept?
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A group whose members are descended from a common ancestor and who all possess a combination of certain defining traits
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What are the problems with the biological (book) species concept?
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What about asexual species? What about species present only in the fossil record? What about hybrids between two "species"?
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What are the problems with the morphological species concept?
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How much difference is enough to say these 2 entities are different from one another (sort of subjective)?
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What are the problems with the evolutionary species concept?
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More subjectivity to determine which populations are currently sufficiently isolated to be undergoing independent evolution
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What are the problems with the phylogenetic species concept?
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Basically the same as the morphological species concept, only using DNA. How much difference is enough?
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What are the five pre-fertilization barriers?
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Spatial Isolation
Behavioral Isolation Mechanical Isolation Temporal Isolation Gamete incompatibility |
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What is spatial isolation?
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The two species never come into contact, and, therefore, don't mate
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What is behavioral isolation?
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There are differences in mating behaviors
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What is mechanical isolation?
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There is physical incompatibility between the sexual organs of 2 individuals
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What is temporal isolation?
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A barrier resulting from the timing of reproduction (seasonal)
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What is gamete incompatibility?
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Mating does occur, but the egg and sperm are not compatible, so fertilization does not occur
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What is the most common pre-fertilization barrier?
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Gamete incompatibility
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What is a post-fertilization barrier?
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Most interspecies hybrids often do not survive long after fertilization due to the incompatibility between genes in the different species
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What is speciation?
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The evolution of one or more species from an ancestral form
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What three steps are necessary for one species to give rise to another?
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Isolation of gene pools of population
Evolutionary change in gene pools Evolution of reproductive isolation preventing gene flow if/when populations come back into contact with one another |
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What does allopatric mean?
What is allopatric speciation? |
Different homeland
Populations become isolated due to barriers (mountains, rivers, intraversable terrain) or distance |
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What does sympatric mean?
What is sympatric speciation? |
Same homeland
Isolated by other means |
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What is the founder hypothesis?
Is this related to allopatric or sympatric speciation? |
the idea that the diversity of unique forms in isolated habitats results from divergence of different species from a single founding population
Allopatric speciation |
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What is a vicariant event?
Is this related to allopatric or sympatric speciation? |
A vicariant event would be the appearance of a barrier that causes populations of a given species to become isolated.
Allopatric speciation |
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Is there a solid rule for how much divergence is required before populations become reproductively isolated?
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No
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Gradualism is one of the ways in which populations become reproductively isolated. Define it.
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an accumulation of tiny changes over millions of years
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Puncuated equilibrium is one of the ways in which populations become reproductively isolated. Define it.
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No change for millions of years and then drastic changes that are fairly quick (thousands of years)
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Which way of reproductive isolation does the fossil record tend more often to support?
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Punctuated equilibrium
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Earth is full of variety and the living world is incredibly diverse. What is this variety called?
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Biodiversity
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How many species are known?
What are the estimates for the number of species? |
1.4-1.8 million
10-100 million |
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Why do we not know how many species there are?
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We have not found them yet
They die before we find them We disagree on how to define a species |
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Describe the different ways we have attempted to organize and classify biodiversity into categories.
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We first used plants and animals
Then we went to five kingdom system Now we use 3 Domains and 4 Kingdoms |
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What are the three domains?
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Archaea
Bacteria Eukarya |
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What are the current four kingdoms?
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Protista
Fungi Animalia Plantae |
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What characteristics do the bacteria and archea domains share?
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Unicellular
Prokaryotes Lack complex internal cell structures Tremendously small Incredibly ubiquitous, chemically complex, and diverse |
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How are many of the currently identified bacterial species known?
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They cause disease in humans, other animals, or crops
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Many bacteria do not cause disease in humans or other animals: some have proven tremendously...
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useful in science
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How do bacteria make a living?
What does this do for scientists? |
By surviving in and on other living creatures. They fight off the host immune system.
It points scientists the way toward treating diseases of the human immune system. |
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Bacteria secrete restriction enzymes. What do we use these for?
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Restriction enzymes are used in genetic engineering technology
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Bacteria secrete antibiotics to kill or disable other bacteria. What do we use these for?
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Many of our commerical antibiotics are derived from bacterial prokaryotes.
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Many archaea are well known for living in what type of environment? Give examples
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Extreme environments w/:
High salt High sulfur High temperature (source of Taq polymerase) |
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In the domain Eukarya, which kingdom is the simplest?
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Protista
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Are protista single-celled or multicellular?
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Most are single-celled.
Some are multicellular |
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How old is the oldest fossil record of eukaryotic cells?
How many years later is than than the first prokaryotic cell? |
2 billion years old
1.5 billion years later |
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What three roles do Protists serve for humans?
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Provide energy (algal biofuels)
Pest control (mosquitos) Measure toxicity |
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What is the Cambrian explosion?
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It involves the kingdom animalia.
Animalia appeared about 600 million years ago and within the next 40 million years, all other animal groups had emerged |
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How are animals defined?
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Multicellular organisms
Ingest other organisms to live (heterotrophs) Have the ability to move during at least one stage of their life cycle |
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What is animalia Latin for?
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breath or soul
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What percentage of the kingdom Animalia is composed of vertebrates?
Give examples |
4%
Mammals birds reptiles amphibians fish |
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Describe the poison dart frog and its effects
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It has poison on its skin that can cause paralysis and convulsions. This poison is of interest to biologists searching for new painkilling drugs.
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What percentage of the kingdom Animalia do invertebrates make up?
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96%
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Most invertebrates are what type of animal?
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Insects
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Are fungi more closely related to animals or to plants? Why?
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They are more closely related to animals because they rely on other organisms for their food and DNA shows that they are more closely related to animals.
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How do fungi feed?
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By secreting molecules to break down food and then absorb the nutrients
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Give 2 examples of fungi
What is each used for? |
Yeast: used in brewing industry for fermentation. Also causes dough to rise
Mold: involved in cheese making and is used in penicillin production |
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Through what process do plants make their own food?
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Photosynthesis
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How many years have plants been present on land?
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Over 400 million years
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Describe the first land plants
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They were small and lacked means to transport water from the ground to their leaves
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How did the first land plants evolve?
What did this evolution allow them to do? |
They developed vascular tissue for transport of water and other substances.
This allowed plants to reach tree-size and to adapt to drier conditions |
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How many years ago did flowers appear on plants?
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140 million years ago
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What percentage of known plant species today are flowering plants?
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Over 90%
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How many known mass extinction events have their been?
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5
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What percentage of the species that have ever lived on Earth are now extinct?
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98%
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What is the common element that are probably causes of the mass extinction events?
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Dramatic change in climate/global cooling
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With regard to the potential 6th mass distinction, severe threats fall into what 4 categories?
Which is the greatest threat? |
Loss or degradation of habitat
Introduction of non-native species Over-harvesting Effects of pollution The greatest threat is loss or degradation of habitat |
