Terms in this set (80)
changes that have transformed
life on Earth from the beginning to the diversity of organisms in the world today
created the theory of evolution
4 early ideas about evolution
2. Buffon, Cuvier, and Lyell
3. Erasmus Darwin
classification system (grouped by similarities)
Buffon, Cuvier, and Lyell
species shared ancestors and changed over time
• age of earth was key issue in early debates
• fossils found in different layers of rock (geology)
• Lyell influenced Darwin
increasing complexity of ancestors; Charles Darwin's grandfather
environmental change leads to use or disuse of a structure
3 theories of geologic change
shaped landforms and caused species to become extinct; volcanoes and floods
slow changes over time
the geologic processes that shape Earth are uniform through time
difference in physical traits among individuals of a group
variation exists within the...
inherited traits of the individuals
phenotype can affect ability to...
find food and reproduce
what affects an organism's phenotype?
it's genotype and environment
a feature that allows an organism to better survive in its environment
organisms that survive are more likely to...
which organisms will become more prevalent through generations?
those that have beneficial inherited traits
what is likely to happen to organisms that have a harder time obtaining food, shelter, or oxygen?
less healthy and likely to die before reproducing
which genes will become more frequent in a population over time?
those that code for beneficial characteristics
Darwins ideas (3)
1. noticed variation in plants and animals
2. proposed that adaptations arose over many generations
3. found fossils of extinct animals high in mountains
humans change a species by breeding it for certain traits
individuals that have inherited beneficial adaptations produce more offspring than other individuals
4 main principles of natural selection
variation, overproduction, adaptation, descent with modification
differences in traits among a population
allows only a limited number of offspring to survive
allow members with advantageous traits to survive and reproduce; also know as "survival of the fittest"
descent with modification
natural selection can produce populations that have different structures from their ancestors. each successive species will have descended with adaptations
A group of similar organisms that can breed and produce fertile offspring but cannot breed with other groups
all the individuals of a species that live in an area
ability of a trait to be passed down through generations
measure of the ability to survive and reproduce
does natural selection change alleles?
which evolve-populations or individuals?
study of prehistoric life
traces of organisms that lived in the past
extinct species that existed between the common ancestor and today's species = "missing links"; fossils
what is proof of evolution/ decent with modification?
study of the distribution of organisms around the world
study of embryonic development
the similar features of embryos in different organisms suggest evolution from a...
distant common ancestor
study of structures of organisms
similar in structure but different feature
examples of homologous structures include:
the human hand, the bat wing, and the mole foot
similar function; not the name origin; like the bat and insect wings
unused physical structures believed to have had a function in an early ancestor; examples: ostrich wings, human appendix, human tailbone
chemical process in an organism. studies genes and proteins to support evolution
all organisms have:
fats, DNA, proteins, carbs
genetic variation within a population:
increases the chance that some individuals will survive
what or where is genetic variation stored in a population?
the combined alleles of all the individuals in a population
a measure of how common an allele is in a population
what formula is used to find calculate the allele frequency?
# of specific allele/total # of alleles
random change in DNA which can for a new
crossing-over during meiosis
frequency is high near the mean and decreases at each extreme
what does normal distribution show?
phenotypes that provide an equal chance of survival
changes in allele frequencies over time
• affects a single population
• genetic changes that determine traits
one extreme phenotype is favored by natural selection
individuals with the intermediate phenotype have the highest fitness
both extremes are favored and intermediate phenotype is selected against
the movement of alleles from one population to another
what does gene flow increase?
genetic variability of the receiving population; the less gene flow that occurs between two populations, the more genetically different they become
random change in frequency of alleles of a population over time; occurs in small populations and is due to chance; can be caused by the bottleneck and founder effects
occurs after a destructive event leaves only a few survivors and decreases genetic variation
a small number of individuals colonize a new area
limits the frequency of the expression of certain alleles; have no preference in who they mate with
individuals choose their mates based on phenotype
process of forming a new species from an existing species; new species can form when organisms in the population are separated and cannot reproduce
isolation can cause:
4 types of isolation
reproductive, behavioral, geographic, temporal
individuals cannot mate successfully because of physical and seasonal differences
differences in courtship or mating behaviors
timing prevents reproduction; reproductive periods may change to a different time of year or a different part of the day
isolation can lead to speciation because...
once isolation occurs, genetic variation and natural selection increase the difference between the populations
unrelated species produce similar structures and behaviors; analogous structures are the result
adaptive radiation; a number of species diverge from a common ancestor, occurs over many generations
two or more species change in response to changes in each other
elimination of a species when the species cannot adapt to its changing environment