Evolution: Evidence and Mechanisms Flashcards
(98 cards)
What is the general definition of evolution?
change over time
What is the definition of biological evolution?
change in organisms over time beyond the lifetime of an indovidual
Is physiological adaptation biological evolution?
no - it happens during one’s lifetime and is not passed on to offspring
What is microevolution?
change on the time scale of generations - changes in allele frequencies across generations
What is macroevolution?
changes at the species level or above, over long periods of time (geological time)
What three topics in biology does evolution explain?
diversity of species, adaptations, common ancestry
Is evolution a scientific fact?
yes
What regarding evolution is debated by scientists?
the relative importance of different mechanisms and how fast evolution occurs (NOT the fact that organisms evolve)
What does the theory of evolution by natural selection explain?
how organisms change over time, becoming more adapted
What evidence (7) is there for evolution?
fossil record transitional forms vestigial structures homologous structures embryology convergence evolved resistance
How does the fossil record provide evidence for evolution?
documents the pattern of evolution, showing that past organims differ from present organisms, showing evolutionary changes that have occured in various groups of organisms
According to the fossil record, what species is the closest living relative to the whale?
hippopotamus
What are transitional forms?
“missing link” - fossils/organisms that show the intermediate states between an ancient organism (reptiles) and a modern one (birds)
Why are transitional forms convincing evidence for evolution?
they show how one form turns into another
What are vestigial structures?
“leftover structures” - remnants of features that served a function in an organism’s ancestors
What are some examples of vestigial structures?
non-functional hind limbs in an ancient whale; pelvic bones in modern whales…
What are homologous structures?
structures in different species that are similar because of common ancestry
What are homologous structures evidence for?
common ancestry
What does embryology show?
shared anatomical features of vertebrate embryos
What is convergence?
process by which non-closely-related organisms independently undergo similar adaptations as a result of having to adapt to similar niches
What are analogous structures?
structures in different species that are similar due to convergent evolution
What two species show convergence?
marsupial mammals of Australia and placental mammals of North America
If one wanted to determine close relations between species, what structures should be examined and which should be ignored?
focus on homologous structures; ignore analagous ons
What are some examples of evolved resistance?
pathogens (viruses, bacteria) become resistant to drugs; insects become resistance to pesticides?