Biology Ch. 16-17-19 Evolution (Birdsell)
Terms in this set (49)
Took a trip on the Beagle
- Galapagos islands
o found several kinds of species that were similar to other species in different parts of the world
o he wrote The Origin of Species
What did Darwin Discover on his adventures
Found several types of species that were similar to other species in different parts of the world
why were fossils important to Darwin?
Darwin noticed that some fossils of extinct animals were similar to living species. Fossils show how extinct species are related to modern species
Natural Selection Concept
Mechanism for change in populations
Organisms with certain variations survive, reproduce, & pass their variations on the next generation. Over time, offspring with favored variations make up most of the population
Lamarck's theory of evolution
Thought species acquired or lost traits based on if they used them or not. Those adaptations could be passed on to their offspring
what was discovered after Lamarck's theory of evolution
organisms don't have an inborn urge to become perfect
survival of the fittest
the organism with certain variations to survive
in the environment
reproduce, & pass their variations onto the next generation
Something you get during your life, but you can't pass on to your offspring
i. e. playing the piano
organisms may live in the same area, but properties prevent them from interbreeding
use of characteristics
using the characteristics an organism has
disuse of characteristics
evidence for evolution
has no function in present-day organism but was probably useful to ancestors
structural features with common evolutionary origin
all start around the same shape and developing slowly changes
: found all over the world
: DNA/RNA have similar sequences
what does fossil evidence mean? What is fossil evidence?
fossils are found all over the world that trace the evolution of modern species from extinct ancestors
all living organisms come from a common ancestor.
: similarity between organisms's amino acid sequences, bone structures and functions
descent with modification
passing traits from parent to offspring through heredity
modern theory of evolution
change overtime through natural selection
Nature provides variations and humans select those they find useful
- purposely breeding plants for bigger fruits
physical and behavior adaptation
things organisms do to survive
gene shuffling (genetic recombination)
- crossing over
- One gene from each parent
small populations have more descendants with an allele
- causes alleles to become more common in a population
relative frequency of alleles (Hardy-Weinberg principle)
allele frequencies in a population should remain constant unless one or more factors cause those frequencies to change
phenotypes vs. alleles
Natural selection acts directly on phenotype, not genotype. In other words, natural selection acts on an organism's characteristics, not directly on its alleles.
favors one extreme of a trait
favors average individuals
favors opposite extremes of a trait
genetic equilibrium in a population
when allele frequencies in its gene pool do not change which means that the population isn't evolving
What does random mating do for a gene pool?
it causes genetic equilibrium
individuals mate with other individuals at random
the evolution of a new species
when members of similar population no longer interbreed to produce fertile offspring
frequency of alleles in a population
What is affected by natural selection?
cause geographic isolation to occur
What do geographic barriers do to a population?
It can lead to distinct subspecies to be formed
bottle neck effect
Change in allele frequency
- follows a dramatic reduction in population size
- usually after a natural disaster or disease
genetic drift results from migration of few individuals
a species has died out
geological time scale (in order)
the geologic time scale is based on both relative and absolute dating. The major division of the geologic time scale are eons eras, and periods
early earth before oceans
conditions needed for life on earth?
- A constant and relatively mild temperature
- Oxygen, Nitrogen, and Carbon Dioxide
How does sexual reproduction affect evolution
it increases genetic variation
significance of Cambrian Explosion
It was the time when animals started showing up in the fossil record
the time required for half of the radioactive atoms in a sample to decay
method of dating rocks and minerals using radioactive isotopes
method of determining the age of a fossil by comparing its placement with that of fossils in other rock layers
a group of organisms share a most recent common ancestor.
how environment affects evolution?
If the environment changes, some organisms will have characteristics that make them better able to survive than others, and these individuals will be more likely to pass on their genes to future generations.
How do you increase/decrease a population?
The population is increasing due to fall in mortality.
The population is decreasing due to a rise in mortality
Which came first DNA or RNA? Why?
RNA because From a simple RNA- based system, several steps could have led to DNA-directed protein synthesis
The endosymbiotic theory proposes that a symbiotic relationship evolved over time, between primitive eukaryotic cells and the prokaryotic cells within them
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