Biodiversity Exam
What is a trochophore?
A distinctive type of larva with a band of cilia
The 150-million-year-old Archaeopteryx fossil has birdlike features such as feathered wings, but it also has characteristics that we associate with living reptiles. Which of the following are considered reptilian characteristics of Archaeopteryx?
Teeth in the jaws, long, bony tail, claws on the ends of each digit in the "hands".
The human population of Madagascar doubles about every _______.
25 years.
What percent of the plant species found on Madagascar are unique to that island, despite Madagascar's having only 2% of the land area of Africa?
80%.
What is a dorsal, hollow nerve cord?
A bundle of nervous tissue running the length of the body, may develop into the brain and spinal cord.
What is a notochord?
A flexible, rod-shaped structure that runs along the anterior-posterior axis, may be associated with a jointed skeleton.
Which anatomical features of the 3.2-million-year-old Australopithecus fossil known as "Lucy" suggest she was a bipedal hominid?
A much shorter hip bone that is broader from front to back and wraps around the side.
Tiktaalik had a combination of fishlike and tetrapod-like characteristics. Which were the tetrapod-like characteristics?
A neck, interlocking ribs, and a flat head with eyes on top. Tiktaalik had characteristics of both fish (scales, fins, and fin rays) and tetrapods (flat head, eyes on top, strong interlocking ribs, and a neck). These characteristics would have enabled it to survive both in and out of water, like amphibians and reptiles toda
Which chordate structure can be used for feeding and gas exchange?
A pharyngeal gill slit is an opening into the throat that can be used for feeding and gas exchange.
What is a lemur?
A primate only found on Madagascar.
What is a muscular, post-anal tail?
A structure that contains muscles and extends past the anus, may be used to propel some species in water.
What do all deuterostomes have in common?
All deuterostomes have a similar pattern of early embryonic development (anus forms before mouth). All deuterostomes are triploblastic and have three tissue layers. All deuterostomes have a coelom.
Compare amniotic eggs to placentas.
Amniotic Eggs: can be deposited outside the mother's body, embryo is protected by a shell filled with albumin. Placentas: retained within mother's uterus, rely on the exchange of gases, nutrients, and wastes with the mother. Both: protect & nourish growing embryos, made of a chorion, yolk sac, and amnion, adaptive strategies for life on land/away from water.
Which of the following is a tetrapod?
Amphibians, Reptiles, Birds, Mammals.
What is a biodiversity "hotspot"?
An area with high species richness and high threat to those species.
Which statement supports the conclusion that the common ancestor of modern chimps and modern humans lived around 7 million years ago?
Analysis of modern human and modern chimpanzee protein and DNA sequences suggests that their lineages diverged about 7 million years ago.
Which protostome phyla successfully made the transition from water to land?
Annelida, Arthropoda, Mollusca, Nematoda
Which primate groups is most closely related to humans?
Apes, such as chimpanzees, are the primates most closely related to humans.
What did scientists learn from other fossils found in the same sediment layer as Ardi?
Ardi lived in a woodland habitat.
Evolution often results in the co-option of a preexisting structure for a new use. Complete three examples to support this statement
Arms were co-opted for use as wings. Scales made of keratin were co-opted for use as feathers. Fins were co-opted for use as limbs.
Which shared characteristics of living birds and theropod dinosaurs provided support to the hypothesis that birds evolved from dinosaurs?
Birds and many theropods have feathers. Birds and many theropods have a wishbone (or furcula). Birds and theropods have S-shaped necksbirds and theropods have hollow bones that are strong, but light.
Which structures are innovations that occurred during vertebrate diversification?
Bone, Jaws, Amniotic egg
One trait that is shared by the Lophotrochozoa and Ecdysozoa is_____.
Both groups are bilaterally symmetric triploblasts with the protostome pattern of development.
Nematodes and arthropods are the largest ecdysozoan phyla. Compare/contrast the two.
Both nematodes and arthropods must molt in order to increase in size. Arthropods possess an open circulatory system. Both nematodes and arthropods possess an external covering, or cuticle. Arthropods are named for their jointed appendages. Some nematodes are parasitic on humans.
Some biologists prefer to focus efforts on preserving endangered species while others prefer to focus on preserving ecosystems. What is your advice to biologists that are choosing which way to follow?
Both types of efforts are needed; their relative importance depends on the circumstances.
Much of the original forest cover on Madagascar has been destroyed primarily as a result of _____.
Burning for agricultural purposes.
How do scientists know that the hominid called "Ardi" is about 4.4 million years old?
By using radiometric dating techniques on the volcanic deposits found above and below the layer containing Ardi.
The phylum Arthropoda includes four major lineages: cheliceriforms (also called chelicerates); myriapods; insects and their relatives (together called hexapods); and crustaceans. Drag each word or phrase to the appropriate bin.
Cheliceriforms: horseshoe crabs, arachnids, possess clawlike feeding appendages Myriapods: millipedes, centipedes, exclusively terrestrial Insects: butterflies, wings that allow flight, body divided into three tagmata (head, thorax, abdomen), three pairs of walking legs Crustaceans: crabs, isopods, two pairs of antennae, primarily aquatic
Which characteristics define a chordate?
Chordates are defined by the presence of four morphological traits: a notochord, a dorsal nerve cord, pharyngeal gill slits, and a tail behind the anus.
Describe Coleoptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Coleptera Wing Characteristics: Hard forewings protect membranous hindwings Type of Development: complete metamorphosis Examples: Beetles
Describe Diptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Diptera Wing Characteristics: hindwings reduced to stabilizers Type of Development: complete metamorphosis Example: flies
Describe Hemiptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Hemiptera Wing Characteristics: Thick forewings (except at tips) Type of Development: incomplete metamorphosis Example: "true bugs"
Describe Hymenoptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Hymenoptera Wing Characteristics: membranous forewings and hindwings Type of Development: complete metamorphosis Example: ants, bees, wasps
Describe Lepidoptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Lepidoptera Wing Characteristics: wings have scales Type of Development: complete metamorphosis Example: butterflies, moths
Describe Orthoptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Orthoptera Wing Characteristics: one pair of leathery wings, one pair of membranous wings Type of Development: incomplete metamorphosis Example: grasshoppers, crickets
Describe Trichoptera
Classification/Taxonomy: Protostome, Ecdysozoa, Arthropoda, Hexapoda, Trichoptera Wing Characteristics: hairy wings Type of Development: complete metamorphosis Example: caddisflies
A human activity such as draining a wetland ___________ ecosystem diversity.
Decreases.
Extinction _________ species diversity.
Decreases.
Which characteristic distinguishes echinoderms from the other two deuterostome lineages?
Echinoderms exhibit a UNIQUE BODY PLAN characterized by an endoskeleton and a water vascular system.
Which statement is true about endothermy in mammals and birds?
Endothermy arose independently in these two lineages via convergent evolution.
Summarize what can happen upon the introduction of exotic species into ecosystems.
Exotic, or non-native, species often disrupt the ecosystem where they are introduced. Exotic species may prey on native species, outcompete native species for resources, or infect native species with new diseases. Sometimes, exotic species can change the environment to such an extent that it is no longer habitable by native species.
Which traits can be used to differentiate humans from our closest living primate relatives?
Extensive tool use, bipedality (the ability to walk exclusively on two legs), and relatively large brain size.
True or false? An organism that is radially symmetric has many well-developed head regions.
False - no head region
True or false? Both echinoderms and chordates have a post-anal tail.
False.
Which statements about bird evolution are accurate based on the evidence presented?
Feathers may have originally evolved for insulation. Feathers may have originally evolved for interspecies communication and display.
Which evidence supports the hypothesis that four-limbed animals came from fish?
Fish and four-limbed animals have very similar embryos. Both fish and four-limbed animals are vertebrates. DNA analysis shows that fish are tetrapods' closest relatives. The fossil record shows more and more tetrapod-like fish before the appearance of tetrapods about 365 million years ago.
What are pharyngeal clefts?
Grooves that separate pouches along the side of the pharynx, may develop into parts of the ear
Most species of hominins are known only from Africa. Which species have been found in other parts of the world as well?
H. erectus, H. neanderthalensis, and H. floresiensis.
Based on what you have learned about global trends in terrestrial ecosystems, what is currently the largest threat to the wet tropical forests in Central America?
Habitat destruction, such as the clearing of forests for coffee plantations.
Summarize habitat loss and fragmentation.
Habitat loss and fragmentation are the greatest threats to biodiversity. Fragmentation can lead to genetic isolation of smaller populations and increased probability of local extinction of some species, especially large mammals. Draining wetlands, clearing tropical forests, and destroying ocean bottom structures are examples of habitat loss.
The primates that spend the most time walking upright are the _____.
Hominids.
Humans are _______.
Homo sapiens.
Brachiopoda is a phylum within the Lophotrochozoa. Even though they are not closely related to bivalve mollusks (such as clams or mussels), brachiopods look and act like bivalve mollusks. Specifically, brachiopods suspension feed, secrete calcium carbonate shells with two valves that hinge together in some species, and attach to rocks or other hard surfaces on the ocean floor. How is it possible for brachiopods and bivalves to be so similar if they did not share a recent common ancestor?
If the distinct ancestors of brachiopods and mollusks lived in similar habitats and experienced natural selection that favored similar traits, then they would have evolved to have similar forms and habitats. This is called convergent evolution.
Why is the common phrase "humans and animals" not accurate in biology? Suggest one way that a more scientific outlook could boost conservation efforts.
In biology, humans are a type of animal, so saying "humans and animals" is incorrect. Switching from a "humans and animals" to a "humans and other animals" world view could encourage conservation in a number of ways. For example, if people feel more closely related to other animals, they may feel more motivated to prevent extinctions. Likewise, if people feel more closely related to other animals, it may seem more obvious that humans are part of ecosystems, increasing motivation to reduce our negative impacts on ecosystems.
Human Evolution........
In the latest phase of human evolution, there has been a greater reliance on culture. The first humans evolved in Africa. The fossil record contains creatures with features that are intermediate between those of modern humans and quadrupedal apes.
High genetic diversity within a species ________ the likelihood that the species can adapt to new environmental conditions.
Increases.
Low genetic diversity within a species ________ the likelihood that the species may go extinct.
Increases.
The number of habitat types _______ when ecosystem diversity increases.
Increases.
Evaluate this statement: Evolution is said to occur when new traits accumulate over time, increasing complexity.
It is true that evolution occurs when new traits accumulate, but it is false that evolution only occurs when new traits accumulate. Evolution can occur when traits are lost. Some lineages adapt to their environments by becoming less complex over time.
What is the function of the arthropod exoskeleton?
It provides protection and functions in locomotion.
Lancelets and tunicates are two groups of chordates. Classify each statement as applying to lancelets, tunicates, or both.
Lancelets: All chordate characteristics are present in adults, adults swim by the contraction of a series of muscles along the notochord, adults bury themselves into the sediment of the seafloor. Tunicates: Larvae swim using the notochord but adults may be sessile, most chordate characteristics are not present in adults, in adults: water enters through one siphon and exists through another. Both: Adults feed with the assistance of pharyngeal slits.
What trait(s) characterize(s) the sarcopterygii?
Lobed fins.
Why have we NOT found examples in the fossil record of every animal that ever lived on Earth?
Many fossils remain buried. We can only find them when they are exposed by erosion or excavation. To become a fossil, an animal must be quickly and completely buried in ash or sediment before it has a chance to decompose. To become a fossil, an animal must remain buried for thousands or millions of years until it (and the layer around it) turns to rock.
Which of these anthropoid groups consists of primates who are mostly tree dwellers and whose forelimbs and hind limbs are about equal in length?
Monkeys.
Are deuterostomes monophyletic or paraphyletic?
Monophyletic.
Are protostomes monophyletic or paraphyletic?
Monophyletic.
Are the Ecdysozoans monophyletic or paraphyletic?
Monophyletic.
Are the Lophotrochozoans monophyletic or paraphyletic?
Monophyletic.
The researchers observed a strong correlation between the number of arthropod species and the number of plant species in the San Lorenzo forest. Complete an evolutionary hypothesis to explain this correlation.
Most of the arthropod species are insects that experienced an adaptive radiation on land thanks in part to the coevolution with plants. Such an evolutionary event created more types of habitats and food sources these arthropods could use. This increased their ecological opportunity for speciation.
Which of these primate groups lives in trees in Central and South America and have nostrils that are wide open and far apart?
New World Monkeys.
What are pharyngeal slits?
Openings to the outside of the body along the side of the pharynx, may develop into gill slits.
Explain overexploitation.
Overexploitation is the harvesting of organisms faster than they can reproduce. For example, some scientists estimate that there may have been 3 to 5 billion passenger pigeons in North America when Europeans first arrived. Hunters began overharvesting these pigeons in the 1800s, leading to a notable decrease in numbers and contributing to the extinction of the species.
What is the primary cause of endangerment in marine environments?
Overexploitation.
Are invertebrates monophyletic or paraphyletic?
Paraphyletic.
There is some evidence that pharyngeal slits occur in certain species of echinoderms that appear early in the fossil record. If confirmed, what do these data suggest?
Pharyngeal slits were present in the earliest echinoderms and lost later.
_____ are the oldest known primate group.
Prosimians.
What two major lineages make up the living Amniota?
Reptiles & Mammals
About a third of insect species measured are in decline, meaning that their populations are shrinking due to habitat destruction, pollution, and other factors. Define how this change affects the bee pollination of crops such as apples and almonds.
Since apples and almonds are cross-pollinated plants, the success of their fertilization depends on the size of bee populations. If bee populations are declining at the same or similar rate as for insects overall, losing a third of bee species could seriously affect the harvest of crops like apples and almonds.
Which size forest fragment would be most affected by habitat fragmentation over a given period of time?
Smaller forest fragments would be most affected.
What is the cause of the red color of the waters about Madagascar?
Soil that has washed into the ocean.
A key characteristic of modern birds is flight powered by feathered wings. Which of the following pieces of evidence support the hypothesis that the first feathers served a purpose other than flight?
Some feathered theropods were not capable of flight. A rich diversity of theropods with various feather structures and from different ages supports the hypothesis that feathers evolved long before flight.
Use your understanding of insect evolution to define main adaptations for terrestrial living that occurred in spiders.
Spiders have internal respiratory structures and a waxy cuticle on the outside to minimize water loss and internal fertilization that prevents germ cells from drying out.
Why was the evolution of the wing such an important event in the evolution of insects?
The ability to fly allowed insects to disperse to new habitats, find new food sources more efficiently, and escape predators.
What was the importance of the development of amniotic eggs?
The development of an amniotic egg and internal fertilization allowed vertebrates to reproduce away from water.
Why was the discovery of organisms, such as Archaeopteryx, that have a mix of traits usually associated with two different groups considered validation of Darwin's theory of evolution?
The discovery provided evidence that species descend with modification from other species.
Which statement about the effects of forest fragmentation on plant biomass and species diversity is true?
The loss of plant biomass has a domino effect on other species that live in the forest fragment.
What does species richness refer to?
The number of species in an area.
How is the opossum related to you?
The opossum and I are both tetrapods. An opossum is a marsupial, but I am a placental mammal.
Which discovery ultimately overturned the prevailing perception that all dinosaurs were large, slow, and lumbering?
The small theropod dinosaur Deinonychus, which had a large sickle-shaped claw on each of its hind limbs. Deinonychus's anatomy, including its sickle-shaped claw, pointed to its being a very agile and quick predator. After its discovery by John Ostrom, most scientists began to see dinosaurian biology and behavior differently.
How did the great transition from fish to tetrapod occur?
The transition occurred gradually over time, so there are many intermediate forms. Most major evolutionary changes, like the evolution of birds from dinosaurs or tetrapods from fish, are products of many small evolutionary steps. Over millions of years, these steps leave behind a series of transitional fossils.
Propose an explanation for why annelids and arthropods were thought to be closely related, before phylogenetic analyses in the late 1990s.
They have segmented bodies, unlike other protostomes.
What kind of habitat did tiktaalik live in?
Tiktaalik lived in a warm, freshwater swamp. When tiktaalik lived and became fossilized, its location was closer to Earth's equator, where warm, freshwater habitats were abundant. Over time, continental drift moved the pieces of Earth's crust (and all the fossils in the rocks above them) to different locations.
What is the purpose of the one-snip test in a phylogenetic tree?
To identify monophyletic groups. If you imagine snipping the tree with scissors in one place, the branches that would "fall off" represent a monophyletic group.
What is a transitional fossil?
Transitional fossils have features that are intermediate between ancestors and descendants.
True or False? Birds and ray-finned fishes have a notochord and jaws.
True.
True or False? Mammals and turtles are more closely related than are lungfishes and sharks.
True.
True or False? Rays and frogs have vertebrae.
True.
True or false? Biologists studied the effects of forest fragmentation by calculating the difference between the amount of plant biomass in the edges of forest fragments and the interiors of unfragmented forest.
True. Through these studies, biologists found that the edge plots lost about 14 percent of their biomass every two years, starting at two years after the fragmentation occurred.
Evolution can also result in the loss of a trait. Complete three examples to support this statement.
Vertebrae were lost in hagfishes. Amniotic eggs were lost in marsupials and placental mammals. Tails (after the embryonic stage) were lost in great apes, including humans.
The population size of mountain pine beetles in the American Northwest has long been held in check by freezing temperatures during winters. As winters warm, populations of pine beetles are increasing, killing whitebark pine forest. Grizzly bears rely on the nuts of whitebark pine trees. Do you think climate change is affecting the fitness of the grizzly bear population?
Yes, because climate change is decreasing the food supply of the bears, which is likely to reduce their ability to survive or reproduce.