By far the most abundant and widespread organisms on Earth are the _____.
Yaws is a serious skin disease of children in tropical countries, caused by Treponema pertenue, a species closely related to the bacteria that cause syphilis. Individual cells of T. pertenue are helical, relatively long, and flexible like the one pictured below. These cells are known as _____.
cell wall containing peptidoglycan and distinctive ribosomes
Antibiotics exploit differences in structure between prokaryotes and eukaryotes in order to selectively attack pathogenic bacteria without affecting the human host. Unique features of bacteria that are targeted by antibiotics include __________.
Around hydrothermal vents at depths of more than 2,500 m, scientists have found colonies of giant tube-dwelling worms. The worms contain symbiotic prokaryotes that are able to use hydrogen sulfide as an energy source for the synthesis of organic matter from carbon dioxide. The bacteria are _____.
Which of the following is an example of a biofilm?
Sewage treatment facilities depend on __________ to remove most of the organic matter and pollutants from wastewater.
In both groups, cell walls lack peptidoglycan and there are several kinds of relatively complex RNA polymerase.
What is a feature that is true of both Archaea and Eukarya?
Algae are photosynthetic, and protozoans are usually heterotrophic.
In general, how do algae and protozoans differ?
independent acquisition of green and red algae as endosymbionts by many protist groups, with subsequent evolution producing photosynthetic organelles
Several groups of protists have variable modes of nutrition: Some species are photoautotrophs, whereas close relatives are heterotrophs. Such diversity even exists within a single species in some cases. Evidence suggests that this pattern is a result of the __________.
unicellular and multicellular autotrophic algae and unicellular heterotrophs and mixotrophs
The newly defined protist group SAR consists of __________.
Amoebas move and feed by using _____.
Some American soldiers serving in Iraq have become infected with a skin disease caused by a protist called Leishmania, which is transmitted by sand flies. The Leishmania organism bears flagella with a unique crystalline rod structure. One of its life stages is squiggly and worm-like in appearance, much like its relative in the same group, Trypanosoma. Leishmania belongs to the group __________.
plasmodial slime mold
While walking in the woods, a student encounters a brightly colored organism with a flat, branching structure growing on a decaying branch. Back in the laboratory, she finds it contains continuous cytoplasm with no clear cell boundaries and hundreds of nuclei. This organism is most likely a _____.
a lakeshore or marsh with water levels that rise and fall frequently
This type of setting would promote the fitness of individuals with traits that help them survive and reproduce despite water loss.
Imagine that a biologist discovers a new species of green algae that has a cuticle-like waxy coating and some rudimentary structures for containing and protecting the gametes. These clues suggest that the new species is very similar to the direct ancestors of the land plants. Where would such a find most likely occur?
an apical meristem and retention of the embryo
A student discovers a mat of green organisms living along the edge of a stream and suspects it is a moss. To confirm that this organism is a moss and not a green alga, he should look for _____.
plants have a distinct, multicellular haploid phase
Reproduction of plants differs from reproduction of animals in that _____
gametophyte is the dominate stage in liverworts and mosses
A common species of liverwort typically resembles a flat green ribbon that occasionally sprouts umbrella-shaped structures. If liverworts and mosses are very similar structurally, then the “ribbons” are _____ and the “umbrellas” are _____.
sporangia and spores
Eventually, it was discovered that ferns produce spores in tissue under their fronds in structures called sporangia
At one time, many people thought that ferns were magical. How did new fern plants form if there were no seeds? This question was answered with the discovery of __________.
lycophytes and tree ferns
This mix of plants was present before the Carboniferous. Seedless vascular plants were well-developed and diverse in the Carboniferous.
In exploring for coal deposits, geologists sometimes look for fossil indicators: fossilized remains of Carboniferous plants. Which of the following combinations in a sample would suggest the presence of rocks that might bear coal beds?
they have seeds and pollen
Unlike mosses and ferns, pines can thrive in arid regions because _____.
The seed is diploid as it is the first stage in the life cycle of the sporophyte.
Gingko biloba, a common urban shade tree, is a gymnosperm with a life cycle that is like that of the pine. Which of the following would be haploid?
In angiosperms, pollen grains are released from the _____, land on the sticky _____, and develop a tube down the length of the style to the ovules.
seeds and pollen
Which two features do angiosperms and gymnosperms have in common?
female gametophyte; egg
Pollen is to sperm as _____ is to _____.
an animal eating the fruit and defecating the seeds
A species of tree produces clusters of dense, fleshy red berries. The seeds of this tree are most likely dispersed by _____
female: drab with large sticky stigmas; male: drab with many large anthers
Wind-pollinated plants are usually drab. Female flowers have relatively large sticky stigmas to provide a large “target” for windblown pollen. Male flowers have large anthers to produce a large volume of pollen grains, which is required given the highly random nature of wind pollination.
Which combination of traits would you expect in the female and male flowers of a wind-pollinated plant?
Not all fungi are decomposers. For example, some fungi are parasites.
All fungi __________
Yeasts reproduce asexually through __________, and molds reproduce asexually through __________
structures associated with sexual reproduction
An important drug for organ-transplant patients is derived from a fungus that until recently was placed in the imperfect fungi category. Its classification was changed when a student at Cornell University discovered _____ in the species.
during the fusion of two hyphae from different mycelia
In basidiomycetes, the equivalent of fertilization occurs _____.
These are the only fungi with flagellated spores.
Zygosporangia are characteristic of zygomycetes, not basidiomycetes.
Corn smut is a fungal disease of corn. However, some people like to eat the corn smut fungus. Corn smut, like market mushrooms, is a club fungus, so it should possess-
benefit fish by helping insects obtain nutrition from dead leaves
Fungi rapidly colonize leaves that fall into freshwater streams. They break down the cellulose in the leaves and absorb the glucose produced. In turn, the fungi serve as food for many insect species that consume the leaf litter; these insects cannot digest cellulose themselves, but gain the nutrients from cellulose indirectly. The insects then provide vital food for stream fish. Taken together, these relationships suggest that fungi __________
Healthy plants and forests could not be sustained without mycorrhizal fungi and fungal decomposition.
Many people see some fungi as dangerous pathogens or destroyers of crops and food. Which of the following claims concerning the beneficial nature of fungi is true?
on a statue in a city known for its polluted air
In which of the following locations would you LEAST expect to find a lichen growing?
has muscles and nerve cells
A researcher discovers a mysterious unknown multicellular eukaryotic organism. She would be confident that it is an animal if she observed that it __________.
She should determine the mechanism by which the mouth forms by examining a series of early embryos.
A researcher finds an animal from a previously unrecognized group. Shee dissects it and finds that it clearly has a true coelom. What additional properties could she check next to further categorize this animal?
Our most current understanding of animal phylogeny is based on __________.
A spectacular marine animal has a network of glassy spicules that forms a cagelike structure. This animal does not have true tissues. It is a suspension feeder. What cells or structures does this cage-building animal use to get nutrients from its feeding cells to other parts of its body?
A group of parasites called myxozoans have traditionally been considered simple multicellular protists. However, because these organisms possess stinging cells, some scientists consider them to be animals in the phylum that is named for such cells, the _____.
At the Sand Bar restaurant, customers can nibble on snails (_____) with garlic butter and oysters on the half shell (_____) during their “happy hour.” The happy patrons will be enjoying what types of molluscs?
flukes and snails
Schistosomiasis is a debilitating disease that affects some 200 million people. It is caused by a parasitic flatworm that is transmitted to humans through contact with an air-breathing mollusc. The parasite and mollusc, respectively, are _____
leeches, a type of annelid
Children sometimes pick up “bloodsuckers” in ponds, but these segmented animals typically spend most of their time parasitizing turtles. Some are used medicinally to improve blood flow and reduce inflammation near injuries in humans. They are _____.
A fearsome predator lurks in the dark corners of human dwellings. It has many similar body segments, with a single pair of long legs on each, and a pair of poison claws. This animal would be a _____
Insects that undergo incomplete metamorphosis do not form pupae.
What is the difference between complete and incomplete metamorphosis?
arthropods and velvet worms have the same set of genes, but these are expressed at different body locations in each group of animals
When comparing gene content and gene expression of homeotic genes in arthropods versus velvet worms, scientists discovered __________.
Pikaia gracilens is an extinct invertebrate animal described from the wonderful pre-Cambrian soft-bodied fossils of the Burgess Shale in British Columbia. Examinations by paleontologists have revealed that organisms belonging to this species had a prominent notochord and segmental muscles. From this information, you could conclude that it is closely related to __________.
the structure and composition of the skeleton and the structure and arrangement of the fins
A biologist visited a fish market and found a fish she did not recognize. To place the unknown fish into a major group, she would need to look at __________.
Tiktaalik lacks the derived features present in mammals.
Tiktaalik is an example of a transitional form linking __________ to ancestral __________.
moist skin and soft, unprotected eggs laid in water
Which of the following traits tend(s) to tie amphibians to wet or moist habitats?
amniotic egg and scaly skin
The tuatara is a lizard-like reptile found only in New Zealand today, the last surviving lineage of a large group of reptiles that were contemporaries of the dinosaurs. Which of the following traits would you expect the tuatara to possess?
absence of teeth, honeycombed bones, and acute sight
Which of the following traits support(s) advanced flight capabilities in modern birds?
A scientist discovers a new species of fossil tetrapod. The fossil consists only of a few scattered hard parts. Which trait would be most likely to allow the scientist to identify the unknown as a mammal?
A researcher found that the reproductive success of bumblebees decreased when the population density of honeybees increased. The decline in the number of bumblebees appeared to be a result of competition for nectar.
Which of these research topics would be considered an example of community ecology?
In tropical forests, there are plants known as ant-plants. These plants host ant colonies. When the ant colony is the species Petalomyrmex phylax, the presence of the ants protects the ant-plants from predation by herbivores. However, the ant species Cataulacus mckeyi takes advantage of the nesting place and nectar the plants provide without affording any protection to the plant. The interspecies interaction between the ant-plants and P. phylax is an example of __________ whereas the interaction between the ant-plants and C. mckeyi is an example of __________.
Two species of cattail in the same genus live at the margins of a lake but at different water depths. If the one that prefers shallow water is removed, the deep-water species occupies deep and shallow water.
two species contend for the same resource
Which of the following is an example of interspecific competition?
Some biologists have observed Egyptian Plovers, a type of bird, land on the open mouth of a Nile crocodile without being eaten and remove leeches stuck firmly to the crocodile’s gums.
Which of the following is an example of mutualism?
Sea anemones coating the shallow-water coral reefs in Australia feed on fish and shrimp that wander too close to their tentacles.
Which of the following is an example of predation?
Squirrels in the forests of Wisconsin hide away hickory nuts and acorns, which they will eat during the long, cold winter.
Which of the following is an example of herbivory?
Early in the 20th century, the American chestnut population was devastated by a non-native fungal pathogen. It has never recovered.
Secondary succession occurs when the vegetation cover of an area has been disturbed by forces such as fire, wind, or over-grazing.
One of the dominant tree species in the temperate deciduous forest in the eastern part of the United States used to be the American chestnut. Now, the dominant tree species are mixed oak and hickory trees and other hardwood trees. What is the reason for this change?
grasshoppers are primary consumers
Consider the following prairie food chain. Tall grass is consumed by grasshoppers that, in turn, are eaten by mice, and the mice are eaten by prairie kingsnakes. Red-tailed Hawks prey on mice and prairie kingsnakes. When a Red-tailed Hawk dies, bacteria, beetles, fungi, and many types of worms help break down the body. Which of the following correctly identifies a trophic level in this ecosystem?
cacti would suffer from increased herbivory
It is more likely that the population of owls would increase, because the food supplies of snakes and owls overlap.
If the snake population were suddenly reduced because of a virus that kills only snakes, we would expect that the population of
a plant community with 12 different species in which each species consists of only about 100 plants
Which of the following represents a community with the greatest species richness?
a keystone species
A keystone species is a species that has a greater impact on the community than would be expected based on its relative abundance or total biomass.
Without elephants, some of the grasslands in Africa would eventually become thickets or forests because elephants weed out trees and shrubs. Even though elephants make up a small percentage of the animals living on the grassland, the grassland would eventually cease to exist without them. In this community, elephants are __________
This community is situated on the banks of the Mississippi River after a rare and widespread flood has occurred. The waters retreated about two months ago.
Which of the following best describes an example of a community experiencing secondary succession?
tall grass praire in Oklahoma
Which of the following ecosystems is dependent on fire?
An invasive species is a non-native species that can disrupt an existing community though competition, predation, or other detrimental effects on native populations.
Garlic mustard is a cool-season edible herb brought to North America by European settlers in the 1800s. It has no significant natural enemies in North America. It spreads rapidly. When established, garlic mustard becomes a permanent member of the community, often dominating the ground layer habitat. What term describes garlic mustard in the United States?
carbon is recycled
What generally flows in one direction through an ecosystem, from producers up through each level of consumers, and is not recycled
a tropical coral reef
Although the open ocean covers more than 65% of Earth’s surface, its primary productivity is very low. Productivity in the ocean increases near shore, where nutrients are more abundant.
Which of the following ecosystems would probably have the highest primary productivity? Assume that we are comparing similar sizes of each ecosystem.
In an ecosystem where 500,000 kcal of sunlight is available for producers, approximately how much chemical energy will be contained in secondary consumers?
The loss of energy from one trophic level to the next means that the consumption of meat is economically and environmentally expensive.
Our current ability to feed the people of the world would improve if people ate a diet that only consisted of __________.
Which of the following is an abiotic reservoir?
the burning of larger amounts of wood and fossil fuels
The main cause of the recent increase in the amount of carbon dioxide in Earth’s atmosphere is _____.