1. Evolution_PreTest_0.5 – Life Science

2. 1) Smooth brome grass (Bromus inermis) is a perennial cool season grass that was imported into the United States to be used as a forage crop. It has taken to the Americas very well and actually often crowds out native plants. Over the last 70 to 80 years that it has been in the United States, the phenotype (out-ward appearance) of the grass has changed due to slightly different growing conditions from its native Europe. In terms of Evolution, this change in the phenotype and genotype (allele change) over a short period of time due to natural selection is an example of _______________.

3. 1) Smooth brome grass (Bromus inermis) is a perennial cool season grass that was imported into the United States to be used as a forage crop. It has taken to the Americas very well and actually often crowds out native plants.Over the last 70 to 80 years that it has been in the United States, the phenotype (out-ward appearance) of the grass has changed due to slightly different growing conditions from its native Europe. Due to different growing seasons and types of soil, there has been a selective pressure on the plants to grow taller and to rely more on rhizomal growth to compete with other plants for space. This selective pressure on brome plants in the United States to have offspring that are better suited to grow under the conditions found here is called ______________________.

4. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. Within Pooideae, Bromus is classified in the tribe Bromeae (it is the only genus in the tribe). Bromus is closely related to the wheat- grass lineage (tribe Triticeae) that includes such economically important genera as Triticum (wheat), Hordeum (barley) andSecale (rye).Evolutionarily speaking, this process of an organism progressing into different species through a fairly longperiod of time, such as what the descendents of theBromus ancestor have done, is called ____________________.

5. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. One of the ways that scientists have determined this, was for them to compare both DNA and proteins from these grasses to other types and varieties of grass. The grasses that were placed in the subfamily Pooideae were the grasses that had the most common patterns in their DNA and proteins. This method for determining phylogeny (common descent) is called ____________________.

6. 1) Smooth brome grass (Bromus inermis) is native to Hungry in Europe while Bromus arenarius is native to Austria in Europe. From studies done on their DNA, scientists think that they had a common ancestor about 3 million years ago but then separated into two different lineages of plants that can't successfully pollinate each other anymore.This process of organisms separating from each other into new taxa that become separate breeding groups is called _______________.

7. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. Within Pooideae, Bromus is classified in the tribe Bromeae (it is the only genus in the tribe). Bromus is closely related to the wheat- grass lineage (tribe Triticeae) that includes such economically important genera as Triticum (wheat), Hordeum (barley) andSecale (rye).All the grasses in this subfamily have two traits that help them successfully survive: large seeds that have a high germination rate and root-types called rhizomes that spread from the parent plant and then come up many centimeters away and start a new plant by asexual means. Since both of these traits help these grasses thrive in the environments they have evolved in, we call these traits ________________.

8. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. Within Pooideae, Bromus is classified in the tribe Bromeae (it is the only genus in the tribe). Bromus is closely related to the wheat- grass lineage (tribe Triticeae) that includes such economically important genera as Triticum (wheat), Hordeum (barley) andSecale (rye). All the grasses in this subfamily have two traits that help them successfully survive: large seeds that have a high germination rate and root-types called rhizomes that spread from the parent plant and then come up many centimeters away and start a new plant by asexual means.The large-seed trait appears to have come about very quickly in the history of subfamily Pooideae, splitting off the ancestors of the subfamily from the other grasses in a matter of centuries, which is a very short time geologically speaking. This type of evolution where a new species is produced in a very short time span but then retains those characteristics for a long period afterward is called ___________________.

9. 1) Smooth brome grass (Bromus inermis) is native to Hungry in Europe while Bromus arenarius is native to Austria in Europe. Scientists studying these two species are inclined to think that they are closely related species that were probably split into two species by mountain ranges that lie between Hungry and Austria.This discipline of examining where living organisms are found in the present day and how they may have gotten there is called _________________.

10. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. All the grasses in this subfamily have two traits that help them successfully survive: large seeds that have a high germination rate and root-types called rhizomes that spread from the parent plant and then come up many centimeters away and start a new plant by asexual means.The Quaking Aspen (Populus tremuloides) also sends out rhizome root-types that asexually reproduce the parent plant but since aspens and grasses are only distantly related, when we compare the structures of these two species that serve the same function but were produced using a different underlying structure, we call these ______________ structures.

11. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. All the grasses in this subfamily have two traits that help them successfully survive: large seeds that have a high germination rate and root-types called rhizomes that spread from the parent plant and then come up many centimeters away and start a new plant by asexual means. The large seed trait is a trait that does not seem to appear in any other close taxa but rather appears to have occurred only in this group because some of the DNA of the ancestral grass was changed. When the DNA of an organism is changed we call this a ______________.

12. 1) Smooth brome grass (Bromus inermis) is part of the cool- season grass lineage (subfamily Pooideae), which includes about 3300 species that has radiated from a common ancestor that lived about 70 million years ago. Within Pooideae, Bromus is classified in the tribe Bromeae (it is the only genus in the tribe). Bromus is closely related to the wheat-grass lineage (tribe Triticeae) that includes such economically important genera as Triticum (wheat), Hordeum (barley) andSecale (rye).Triticum (wheat), Hordeum (barley) and Secale (rye) in the wild all had fairly large seeds but starting about 3 thousand years ago, humans started to pick and replant seeds from these genera that had larger seeds. Eventually, the modern, very-large seeded cereal grains that we are familiar with were produced. This careful, directed picking of traits that are desired by the humans that are picking them is called ____________ selection.

13. 1) The origin of equines (horses) can be traced to the Eocene period, between 60 and 50 million years ago.Eohippus, or Dawn Horse, was about the size of a Cocker Spaniel - 14 inches at the shoulder - and is thought to have weighed about twelve pounds. He had four toes on the front legs and three on the back, which were padded like those of a dog and allowed easy movement over wet ground. By the Oligocene period, about 38 million years ago,Eohippus had evolved into Mesohippus and Miohippusand had achieved the size of a German Shepherd. Parahippus and Merychippus evolved in the Miocene period, about 26 million years ago.The first truly single-hoofed horse was Pliohippus, which evolved about seven million years ago in the Pliocene period. Equus spread across the Bering Strait from America to Asia. Soon after that the horse became extinct in North America. No one knows why. They were later re-introduced to the continent by Spanish explorers, and became the progenitors of the Mustang.When a lineage of organisms, like the horses, slowly develops (by geological standards) in a steady progression, we call this type of evolution ___________________.

14. 1) The origin of equines (horses) can be traced to the Eocene period, between 60 and 50 million years ago.Eohippus, or Dawn Horse, was about the size of a Cocker Spaniel - 14 inches at the shoulder - and is thought to have weighed about twelve pounds. He had four toes on the front legs and three on the back, which were padded like those of a dog and allowed easy movement over wet ground. By the Oligocene period, about 38 million years ago,Eohippus had evolved into Mesohippus and Miohippus and had achieved the size of a German Shepherd. Parahippus and Merychippus evolved in the Miocene period, about 26 million years ago.The first truly single-hoofed horse was Pliohippus, which evolved about seven million years ago in the Pliocene period.The change from a 4- toed/3-toed horse to a single toed horse allowed the modern horse to run faster on open plains. This kind of a physical change in an organism that helps it in its environment is called a ____________ adaptation.

15. 1) The origin of equines (horses) can be traced to the Eocene period, between 60 and 50 million years ago.Eohippus, or Dawn Horse, was about the size of a Cocker Spaniel - 14 inches at the shoulder - and is thought to have weighed about twelve pounds. He had four toes on the front legs and three on the back, which were padded like those of a dog and allowed easy movement over wet ground. By the Oligocene period, about 38 million years ago,Eohippus had evolved into Mesohippus and Miohippusand had achieved the size of a German Shepherd. Parahippus and Merychippus evolved in the Miocene period, about 26 million years ago.The first truly single-hoofed horse was Pliohippus, which evolved about seven million years ago in the Pliocene period.Scientists were able to piece the progression of the horse ancestors by looking at the remains of early horses in the _________________, one of many ways of finding evidence for evolution occurring.

16. 1) What organelle is shown at “A”?