BIO 1802 Ch 30 Sandboxes

Which of the following is true?

Yeast, nematodes and brine shrimp use the same means to survive desiccation.

Animal tissues develop from embryonic germ layers. Triploblastic animals have three germ layers (ectoderm, mesoderm, and endoderm) and three basic body plans related to body cavities (acoelomate, pseudocoelomate, and coelomate). Select the three statements that are true.

1. In a coelomate, the tissue lining the inner side of the body cavity arises from the same germ layer as the tissue lining the outer side of the body cavity. 2. A diploblast has no mesoderm. 3. A pseudocoelom has the same functions as a true coelom.

Three basic body plans of triploblasts relate to the presence or absense of a body cavity.

1. No body cavity: acoelomate 2. Body cavity lined on the inner side by endoderm-derived tissue and on the outer side by mesoderm-derived tissue: pseudocoelomate 3. Body cavity lined entirely by mesoderm-derived tissue: coelomate

Several variables have been hypothesized to play a role in the sudden appearance of diverse animals during the Cambrian explosion. For example, the "higher oxygen levels" hypothesis invokes an environmental trigger and the "evolution of predation" hypothesis invokes ecological interactions. Erik Sperling, Andrew Knoll, and colleagues set out to test the hypothesis that these two hypotheses are linked. Could the oxygen atmosphere enable the evolution of predation? A: The researchers analyzed 962 polychaete species sampled from 68 field sites worldwide, each from a low-oxygen setting below 150 m water depth. List one or more variables that the researchers likely were trying to control by collecting so many data points.

1. Water, temperature, and depth 2. Current, pH, and type of substrate 3. Polychaete species present and types of other species present in the community

Sperling and Knoll's approach was to compare the number of predatory polychaete worms (pronounced pol-ee-KEET, phylum Annelida) living today in different low-oxygen environments. They chose polychaetes as a model system because these worms have diverse feeding strategies and live in diverse marine environments, yet all have the same basic body plan. Using the figure as your guide, describe the body plan of a polychaete worm.

1. cephalization 2. segmented tube-within-a-tube 3. have a coelom 4. triploblastic 5. central nervous system

The number of phyla of animals currently recognized by biologists is approximately _____

30-35 88

Which of the following is least likely to survive rapid drying out?

A tardigrade with TDP always turned off.

The basic bilaterian body form plan can be thought of as simply _____.

A tube within a tube - The inner tube is the individual's gut, with a mouth at one end and an anus at the other, and the outer tube forms the nervous system and skin.

Which type of symmetry does each of the following animals display?

Asymmetry: sponge Radial: jellyfish, hydra Bilateral: turtle, bobcat, octopus, snake

What is the relationship between choanoflagellates and animals?

Choanoflagellates are considered an outgroup to the animal lineages. - The choanoflagellate lineage diverged before animal lineages diverged from one another

In your body, the outside "tube" that surrounds a cavity and inner "tube" is derived from the ________.

Ectoderm.

Sponges lived in low-oxygen oceans before the Cambrian, and they occur today in both low-oxygen and high-oxygen environments. What aspects of the sponge body plan might have prevented the evolution of predatory sponges in high-oxygen environments? - Effective predators tend to be ____ and they have _____ for detecting prey. Sponges lack _____, _______, and _____ as adults.

Effective predators tend to be mobile, and they have sensory structures for detecting prey. Sponges lack nerves, mobility, and muscles as adults.Animals evolved from simple to complex.

In a tube-within-a-tube body plan, what is the interior tube derived from?

Endoderm

In your body, the inside "tube" within a "tube" is derived from the _____

Endoderm

True or false? Many new major animal body plans have evolved since the Cambrian about 550 million years ago.

False, almost all the major body plans arose rapidly during the Cambrian.

A few sea urchins produce very large yolk-filled eggs that develop directly into juveniles. What arrow on the figure of life cycles would remain the same for these types of sea urchins?

Growth: the juvenile sea urchins would still need to grow into adult sea urchins

Animals that feed primarily or exclusively on plants and algae are classified as _______.

Herbivores: they eat photosynthetic organisms

What reproductive trait is associated with terrestrial environments?

Internal fertilization: greatly enhances the ability of sperm to successfully travel to the egg.

You discover a new subspecies of brine shrimp. In its desiccated form, which of the following do you find?

It contains glass-like solids.

A new intrinsically disordered protein is discovered. Which of the following is true about this molecule?

It lacks a fixed 3-D structure.

Which mouthparts are likely to be the most complex?

Mass feeders: they have to tear and process hard chunks of food

Which of the following traits would help the researchers identify a certain polychaete as a predator?

Pair of jaws

Which phylum includes the most basal lineages of animals?

Porifera

Many animals can be categorized as either protostomes and deuterostomes based on certain features of their embryonic development. Determine whether each of the following terms applies to only protostomes, only deuterostomes, both protostomes and deuterostomes, or neither.

Protostome: diploblast, mouth from blastopore, radial indeterminate cleavage Deuterostome: triploblast, spiral determinate cleavage, anus from blastopore

Which of the following is evidence that supports the hypothesis that sponges are the sister group to all other animals? - What evidence suggests that sponges evolved first?

Sponges share many characteristics with choanoflagellates.

Several variables have been hypothesized to play a role in the sudden appearance of diverse animals during the Cambrian explosion. For example, the "higher oxygen levels" hypothesis invokes an environmental trigger and the "evolution of predation hypothesis" invokes ecological interactions. Erik Sperling, Andrew Knoll, and colleagues set out to test the hypothesis that these two hypotheses are linked. Could the oxygen atmosphere enable the evolution of predation? Describe the logic of the "higher oxygen levels" hypothesis and the "evolution of predation" hypothesis for the Cambrian explosion. - The "higher oxygen levels" hypothesis suggests that animal diversity __________ in response to __________ oxygen levels at the start of the Cambrian. Oxygen enabled aerobic respiration, which provides ________ energy for growth and movement. The "evolution of predation" hypothesis suggests that the _______________ of predators ____________an "arms race" between predators and prey, stimulating diversification.

The "higher oxygen levels" hypothesis suggests that animal diversity increased in response to higher oxygen levels at the start of the Cambrian. Oxygen enabled aerobic respiration, which provides more energy for growth and movement. The "evolution of predation" hypothesis suggests that the appearance of predators started an "arms race" between predators and prey, stimulating diversification.

Why was the evolution of a coelom a critically important innovation for animals?

The coelom can act as a hydrostatic skeleton. - A soft-bodied animal with a coelom acting as a hydrostatic skeleton can move effectively even if it lacks fins or limbs.

Species that have embryos nourished from the female's body during development, followed by birth of live young, are said to be _______.

Viviparous

A few sea urchins produce very large yolk-filled eggs that develop directly into juveniles. Under what circumstances might this be adaptive?

When resources are rich and the sea urchins are well adapted to their environment - These juvenile sea urchins are clones and would likely do as well as their parent in this environment.

You study tardigrades in their tun state. What is this?

When they are desiccated.

Animals evolved from simple to complex. - While it _________ that early animals were ______ than later animals, evolution is more complicated than a _________ story suggests. For example, many essential tool-kit genes evolved ___________ of the animal tree and were later co-opted in various ways in different lineages. Also, sometimes traits are _______ over time, such as a coelom in flatworms and legs in snakes.

While it is generally true that early animals were simpler than later animals, evolution is more complicated than a simple-to-complex story suggests. For example, many essential tool-kit genes evolved right at the base of the animal tree and were later co-opted in various ways in different lineages. Also, sometimes traits are lost over time, such as a coelom in flatworms and legs in snakes

Where would you add bars to the small tree to indicate the evolution of multicellularity?

Within the branch of Animalia and within the branch of fungi

Suppose that a gene originally identified in nematodes (roundworms) is found to be homologous with a gene that can cause developmental abnormalities in humans. Would it be possible to study that same gene in fruit flies?

Yes

Metamorphosis is ______.

a type of life cycle - In animals that undergo metamorphosis, the larval form looks radically different from the adult form.

The expression of the gene dpp in the bilateral form in a variety of animals is evidence that _____.

bilateral symmetry in all animals is homologous - The expression of a single gene in all animals suggests a single evolutionary event.

Which of the following is an example of homology (similarity due to common ancestry)?

cnidocytes (stinging cells) in jellyfish and sea anemones

Which of the following characteristics does not apply to cnidarians?

have a complex central nervous system

Bilateral Symmetry is

he body has left and right sides, a front and back, and a top and bottom.

Predict the circumstances under which sexual reproduction would be favored.

lack of resources, predation, infection

What synapomorphy (shared, derived trait) distinguishes animals as a monophyletic group, distinct from choanoflagellates?

multicellularity

Some sea anemones can produce large colonies by reproducing asexually, but they can also produce planktonic larvae by reproducing sexually. Predict the circumstances under which asexual reproduction would be favored.

plenty of resources such as space and food

Radial Symmetry is

the body is wheel- or spoke-shaped, with no obvious front, back, right, or left.

What recent experimental evidence suggests that all animal appendages may be homologous?

the discovery of the "distal-less," or Dll, gene in many different phyla - Dll appears to be involved in the initial phase of limb and appendage development in all animals, even in phyla with wormlike bodies that have simple appendages.

The phyla Porifera, Cnidaria, and Ctenophora are ________.

the most ancient of all animal lineages - branch off from the base of the phylogenetic tree for animals.