Adaptations
What is an adaptation?
A trait that helps an organism survive
What is natural selection?
Describes the process where organisms with traits better suited to their environment are more likely to survive and reproduce, passing those advantageous traits on to future generations.
One source of evidence of evolution comes from the study of embryos and their development. What is this field of biology called?
Embryology
Answers may vary
Name two mechanisms of evolution.
Any two out of the following:
Natural selection
gene flow
genetic drift
nonrandom mating
mutations
Name one adaptation in a polar bear's physical characteristics
White fur, thickness of fur, blubber to stay warm (answers can vary)
Name all 4 principles of natural selection
Variation, overproduction, adaptations, decent with modification
Explain how embryos provide evidence of evolution.
The similar features of embryos in very different organisms suggests evolution from a distant common ancestor.
If two organisms have homologous structures, meaning body parts with the same build but different jobs, what is the most likely conclusion?
They most likely have a common ancestor
When a natural disaster takes out individuals in a population, lowering the genetic diversity, it is called
genetic drift
How does the long neck of a giraffe help it survive in its environment?
It helps them reach food high in trees that other animals can’t.
In a population of insects, some individuals are resistant to a pesticide. After the pesticide is used for several years, most insects in the population are resistant. What is the best explanation for this change?
Only resistant insects survived and reproduced, passing on the resistance
How can DNA be used as evidence of evolution between a group of organisms?
DNA can be compared between the organisms. The more closely they match, the more closely they are related.
A bat and a bird in an ecosystem both have wings but with different structures. What vocab word is used to describe this?
Analogous structures
How does non-random mating affect genetic diversity in a population?
decreases it.
A species of beetle lives in a desert. Some beetles have light-colored shells, while others are dark. Over time, more light-colored beetles are observed. What is the most likely reason for this change?
Predators can more easily see the dark colored beetles
In a population of rabbits, fur color ranges from light brown to dark brown. A volcanic eruption darkens the landscape with ash. Over time, the number of dark brown rabbits increases while light brown rabbits become rare.
What is the most likely explanation for this change, and how does it demonstrate natural selection in action?
Possible answer: The dark environment made dark brown rabbits harder for predators to see, so they were more likely to survive and reproduce. Light brown rabbits were more visible and likely eaten. This demonstrates natural selection because the environment favored a trait (darker fur), which became more common in the population over time.
Scientists think that dolphins and whales may have evolved from a common ancestor. What evidence could they collect to support this hypothesis?
DNA comparison and/or look for homologous structures and/or fossil evidence that links the two
Both whales and bats have forelimbs with the same pattern of bones, even though whales use them for swimming and bats use them for flying.
What does this suggest about their evolutionary history?
They share a common ancestor.
A group of birds are blown away from the mainland during a storm on an island. The birds establish a new population on the island.
What mechanism of evolution is this an example of?
Genetic Drift.
In a cold environment, some rabbits have thick fur while others do not. A student claims that the thick-furred rabbits will survive and reproduce more successfully. What kind of data could support this claim?
data such as survival rates, number of offspring, or health comparisons between thick-furred and thin-furred rabbits.
Answers may vary but should generally include one or more of the above.
A species of bird feeds on insects hiding in tree bark. Some birds have longer, narrower beaks than others. Over several generations, the average beak length increases. Explain how natural selection could lead to this change and describe what evidence you would collect to support your explanation.
Birds with longer, narrower beaks are better at reaching insects in bark, so they survive and reproduce more.
Evidence to collect (one or more will be accepted)
Data on survival and reproduction based on beak length
Number of insects captured per bird
Changes in beak length over generations
How does biogeography provide evidence of evolution? Explain your reason AND provide an example.
The pattern of closely related species living near each other supports the theory of evolution because it shows that species likely came from a common ancestor and then changed over time to adapt to different environments.
Possible example: Darwin’s finches on the Galápagos Islands are all closely related, but they have different beak shapes depending on the island they live on.
Snakes have tiny pelvic bones that serve no current function in movement. Humans have pelvises that are used for walking upright.
What type of structure is the snake pelvis, and what does it suggest about snake evolution?
a vestigial structure that suggests snakes evolved from ancestors with legs
The African honeybee was introduced into Brazil in the 1950’s . The African bee mated with the western bee population, introducing new genes to the indigenous population (ultimately leading to a new hybrid species commonly known as “killer bees”).
This is example of what type of mechanism of evolution?
Gene flow