Section 29.2 (Exam 2) Flashcards
Animal Life Cycles Involve Trade-Offs
Embryonic development + All stages of life = ?
The Life Cycle
What is direct development?
The newborns look similar to the adults.
In most animals, newborns appear _______________ adults. One example of this is a caterpillar turning into a butterfly.
different from
Many insects undergo metamorphosis. What is metamorphosis?
Radical changes between larva and adult changes.
Larva and adults may feed on ________________.
different foods
The insect larva may be specialized for __________, while the adult is specialized for ____________.
feeding; reproduction
How many dispersal stages do most animals have?
one
What is dispersal when referring to an animal’s dispersal stage?
The movement of organisms away from a parent or existing population
When do most motile animals disperse?
When they are adults (butterflies fly to new places to lay eggs)
How do sessile animals disperse?
Sessile marine animals are able to discharge their eggs and sperm into the water, where they fertilize and travel on water currents.
What are two sessile marine larvae?
Trochophore and Nauplius larvae
What are some characteristics of trochophore larvae? What are some examples of them?
Radially symmetric
Bands of cilia for filter feeding
Annelids and mollusks
What is a characteristic of nauplius larvae?
bilateral symmetry
What do trochophore larvae and nauplius larvae have in common?
Both types feed on the plankton and can travel long distances before settling and becoming adults.
In the parasite life cycle, what are two purposes for which parasites must expend energy?
Overcoming the hosts defenses and dispersing to new hosts.
Parasite eggs could be dispersed in two ways. What are they?
Eggs could be dispersed through a host’s feces and be ingested by a new host.
How many hosts do most parasites have?
More than one
Bryozoans and corals are examples of _________ animals.
colonial
What is fission?
The dividing of something into two or more parts
If asexual reproduction occurs without fission, what can it lead to?
Colonies of physiologically integrated, genetically identical individuals.
In some species, these individuals can become _____________. One example of this is the Portuguese man-of-war.
specialized
Explain why every life cycle has trade-offs. Provide examples.
If energy is devoted towards characteristics that can improve performance in one category, it will reduce performance in some other. For example, the shell of an animal is helpful for protection, but it also takes away energy that could be used for the animal to grow.
How are trade-offs present in reproduction?
Large number of small eggs or small number of large eggs.
If more energy and time is spent towards an egg, what will the resulting offspring be?
It will have developed more and be more independent.
What does it mean if an animal is altricial?
Young are helpless when hatched and must be cared for by parents.
What does it mean if an animal is precocial?
Eggs are incubated longer, and hatchlings can forage right away.
