Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

35 Cards in this Set

  • Front
  • Back
consists of all the individuals of a species that live together in one place at one time
natural selection
process by which populations change in response to their environment
changing of a species that results in its being better suited to its environment
What provides endless sources of new variations?
recombination and mutations of alleles
condition in which 2 populations of the same species can't breed with one another (ex. 2 squirrel populations in the Grand Canyon pg. 281)
disappear permanently
What have fossils provide record of? (3)
1.) Earth is about 4.5 billion years old
2.) Organisms have inhabited Earth for most of its history
3.) All organisms living today evolved from earlier, simpler life-forms
Why are the chances of an organism to be made into fossils be slim?
1.) may decay before buried in sediment
2.) may be eaten by animals & scattered
3.) some bodies decay faster than others
scientists who study fossils, can determine age of fossils using radiometric dating
If evolution has taken place, then species that descended from a common ancestor in the distant past should have ____ _____ _____ sequence differences between their proteins than do species that share a common ancestor more recently.
more amino acid
Nucleotide changes cause changes in __________________________, which scientists can use to approximate the number of these changes
the amino acid sequence of a protein
vestigial structures
means "footprint" structure reduced in size and function; considered to be evidence of an organism's evolutionary past (they may also have no or use/ less important function than they do in other, related organisms)
All vertebrates share ______________.
a common ancestor
homologous structure
structures that share a common ancestry
punctuated equilibrium
periods of rapid change in species are separated by periods of little or no change
industrial melanism
the darkening of populations of organisms over time in response to industrial pollution (best known case: European peppered moth, an example of natural selection)
The process of natural selection depends on what 5 main elements?
1.) all species have genetic variation
2.) environments present challenges to an individual's ability to reproduce
3.) organisms tend to produce more offspring than their environment can support (species often compete)
4.) those better able to cope with challenges of their environment tend to leave more offspring
5.) traits best suited to environment tend to increase in a population over time
accumulation of differences between groups, leads to the formation of new species
process by which new species form
reproductive isolation
the inability of formerly interbreeding groups to mate or produce fertile offspring
What types of barriers are responsible for reproductive isolation?
geographically isolated, may reproduce at different times, physical differences, not attracted
mammalian group that includes prosimians, monkeys, apes, humans
a member of a group of mostly night-active primates that live in trees (lorises, lemurs, tarsiers)
primates that are active during the day and sleep at night
monkeys, apes, humans
opposable thumb
stands out at an angle from the other fingers and can be bent inward toward them to hold an object
What do the genes of humans & chimpanzees have in common?
all 287 amino acids in hemoglobin are the same
What is one difference between humans and gorillas?
they have 2 amino acid differences in hemoglobin
primates that can walk upright on 2 legs
meaning able to walk upright on 2 legs
How old is the most ancient hominid yet discovered?
4.4 million years old found by American anthropologist Tim White
What is the one thing humans have that no other animal is thought to have ever had?
cultural evolution
ecological races
when populations of the same species that differ genetically because of adaptations to different living conditions become this (1st step to speciation)
What are the 2 hypotheses about how HOmo sapians evolved?
1.) independent homo erectus groups living in Africa, Europe, Asia interbred and homo sapiens arose
2.) homo sapiens appeared in one place (Africa) then migrated to Europe and Asia replacing homo erectus as they migrated
How is the theory of evolution supported? (4)
1.) Variation exists within genes (results of random mutation)
2.) some species are better suited to survive (as a result of variation) and have more offspring (natural selection)
3.) traits that make certain individuals of a population able to survive and reproduce tend to spread in that population
4.) there is clear proof from fossils and many other sources that living species evolved from organisms that are extinct.