Adaptations
Animals living in extreme environments often develop traits that improve their chances of survival and reproduction (fitness). These beneficial traits are called?
Adaptations
In every population, some individuals possess traits that make them more likely to survive and reproduce. Over time, these traits become more common through this process.
Natural Selection
When scientists want to determine how closely related two species are, they compare this type of molecular evidence because it is inherited from generation to generation.
DNA
When a mother shrew moves her nest, her young form a chain by holding onto each other's tails. This behavior increases the likelihood that the offspring will do what?
Survive during relocation
The illegal hunting and killing of elephants is known as this term.
Poaching
Yaks live on the Tibetan Plateau, where oxygen levels are much lower than at sea level. Over many generations, yaks evolved larger lungs, larger hearts, and specialized hemoglobin. These adaptations help them survive in what environmental condition?
Low oxygen/high altitude
In areas where elephants were heavily poached for ivory, females born without tusks were less likely to be killed by humans and were more likely to reproduce. What structure was being selected against?
Tusks
Researchers often compare unique sections of DNA that randomly insert themselves into genomes and are passed to offspring. These DNA markers are called:
Transposons / genes
When wolves approach a herd, adult bison form protective circles around their calves. This behavior evolved because it increases what?
Offspring Survival
When humans selectively remove individuals with a certain trait from a population, they create this type of evolutionary force.
Selective Pressure
Pikas are small mammals that live on the Tibetan Plateau. They spend much of their time running through underground tunnels and watching for predators. This survival strategy is an example of what type of adaptation?
Behavioral Adaptation
Researchers observed that in regions with intense poaching, the percentage of female elephants born without tusks increased over time. What happened to the frequency of the tuskless trait?
it increased
Humans, bats, whales, and cats all have forelimbs containing the same basic arrangement of bones, even though they use them differently. These similarities provide evidence for what evolutionary idea?
Common Ancestry
A female bluefin tuna can release millions of eggs at one time, yet only a few offspring survive to adulthood. Why is producing such a large number of offspring advantageous?
Increases the chance that some offspring survive and reproduce
Some African farmers use fences containing active beehives because elephants naturally avoid these insects. What insects are used in this conservation strategy?
Honeybees
About 385 million years ago, a fish-like organism called Tiktaalik had strong fins that allowed it to move through shallow water and onto muddy shorelines. These traits helped it exploit what new environment?
Land/shore Habitat
Natural selection cannot occur if every individual in a population is genetically identical. What must exist in a population before natural selection can act?
Genetic Variation
Tiktaalik possessed traits of both fish and early land vertebrates. Scientists use fossils like this to show how one group evolved into another. Such fossils are called:
Transitional Fossils
Species that produce many offspring but experience very high juvenile mortality are represented by which standard in Darwin's theory of Natural selection?
Too many offspring are produced than the environment support
A population bottleneck occurs when a population becomes extremely small. After American bison numbers dropped to fewer than 1,000 individuals, what characteristic likely decreased?
Genetic Diversity
Modern whales no longer walk on land, but they still possess tiny pelvic bones inherited from ancestors that did. What is the name for structures that have lost most or all of their original function?
Vestigial Structures
Some yaks inherited hemoglobin that could capture oxygen more efficiently in the thin mountain air. These yaks survived and reproduced more often than others. Why did this trait become more common in the population?
individuals with the trait had higher survival and reproductive success. They had higher fitness.
Whales and sharks both have streamlined bodies that help them move efficiently through water. However, whales are mammals and sharks are fish. This similarity is an example of:
Convergent evolution/ analogous structures
Protective behaviors in animals become common over time when individuals exhibiting those behaviors are more likely to survive and leave offspring. This is an example of what evolutionary process?
Humans can unintentionally drive evolution by changing habitats, hunting organisms, introducing pollutants, or altering ecosystems. What is the common biological reason these activities can change populations over time?
they create selective pressures that affect survival and reproduction