Anatomy and Evolution: Key Concepts

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Questions and Answers

Explain how the evolution of a 4-chambered heart provides a selective advantage to warm-blooded animals compared to a 3-chambered heart. How does this relate to energy expenditure?

A 4-chambered heart prevents the mixing of oxygenated and deoxygenated blood, allowing for more efficient oxygen delivery to tissues. This supports the high metabolic demands of warm-blooded animals, enabling them to maintain constant body temperatures, hence expending more energy.

A population of insects is exposed to a new pesticide. Initially, most insects are susceptible, but over generations, resistance increases. Explain how natural selection leads to this outcome, incorporating the concepts of variation and competition.

In the insect population, there's existing variation in pesticide resistance. When the pesticide is applied, susceptible insects die, while resistant ones survive. These survivors reproduce, passing on their resistance genes. Over time, competition favors the resistant insects, leading to an increase in the proportion of resistant insects.

Describe how geographic isolation can lead to speciation. Include a brief explanation of the role of reproductive isolation in maintaining the new species.

Geographic isolation separates a population, preventing gene flow. Over time, the isolated populations accumulate different genetic changes due to mutation, natural selection, and genetic drift. Eventually, reproductive isolation mechanisms evolve, preventing interbreeding even if the populations were to come back into contact, thus forming new distinct species.

Contrast homologous structures and vestigial traits in terms of their significance as evidence for evolution from a common ancestor.

<p>Homologous structures, like the pentadactyl limb in vertebrates, show similar underlying anatomy resulting from shared ancestry, modified for different functions. Vestigial traits, like the human appendix, are remnants of structures that had a function in ancestral species but are now reduced or non-functional, indicating evolutionary change over time from a common ancestor.</p> Signup and view all the answers

Explain the purpose of sexual reproduction in the animal kingdom, and describe how genetic recombination contributes to the evolutionary success of sexually reproducing species.

<p>The purpose of sexual reproduction is to increase genetic variation within a population. Genetic recombination (crossing over, independent assortment) during meiosis shuffles genes from two parents, creating offspring with novel combinations of traits. This enhances a population's ability to adapt to changing environments and resist diseases, contributing to the evolutionary success.</p> Signup and view all the answers

Flashcards

Dorsal

Toward the back (e.g., the spine is on the dorsal side).

Ventral

Toward the front (e.g., the chest is on the ventral side).

Toward the head or front end.

Posterior

Toward the tail or rear end.

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Open Circulatory System

Blood is not entirely contained within vessels; it flows through body cavities.

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Study Notes

Anatomy/Evolution Test Topics

Anatomical Orientation

Dorsal refers to the back or upper side
Ventral means the front or lower side
Anterior indicates toward the head or front
Posterior indicates toward the tail or rear

Circulatory Systems

Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells
Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness. In this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities.

Thermoregulation

Cold-blooded animals are ectothermic, relying on external sources for body heat
Warm-blooded animals are endothermic, maintaining a constant body temperature through metabolic processes

Body Plan

Bilateral symmetry is a body plan where the body can be divided into mirror-image halves along a single plane

Body Systems

Nervous system's purpose is to coordinate actions and transmit signals between different parts of the body

Reproduction

Sexual reproduction's purpose is to create genetic variation within a population

Organ Functions

Esophagus transports food to the stomach
Intestines absorb nutrients from food
Brain controls bodily functions and thought
A 3-chambered heart has two atria and one ventricle, while a 4-chambered heart has two atria and two ventricles
Internal skeletons exist inside the body; exoskeletons exist outside of it
Testes produce sperm
Ovaries produce eggs
Nerves transmit electrical signals; the spinal cord connects the brain to the rest of the body
Kidneys filter waste from the blood
Lungs facilitate gas exchange

Classification

Taxonomy is the science of naming and classifying organisms
Phylogeny is the evolutionary history of a species or group of species
Cladograms and dichotomous keys are tools used to classify organisms based on shared characteristics

Adaptations

Physical adaptations are structural features that enhance survival
Behavioral adaptations are actions that organisms take to survive

Evolutionary Mechanisms

Natural selection is the process where organisms better adapted to their environment tend to survive and reproduce more
Natural selection is a natural process; artificial selection is human-driven
Species and speciation refers to the process by which new species arise

Speciation and Biodiversity

Isolation leading to speciation promotes biodiversity

Genetic Change

Recombination and mutation are sources of genetic change

Evolutionary Evidence

Homologous structures indicate common ancestry because of similar structure and different function
Vestigial traits are remnants of structures that had a function in ancestral species but no longer do

Population Dynamics

Overproduction, competition, and variation are factors that drive natural selection

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Description

Explore key concepts in anatomy and evolution. Understand anatomical orientation including dorsal, ventral, anterior, and posterior. Learn about circulatory systems, thermoregulation and body plans.