Biology Chapters 53, 54 & 56 Flashcards

Questions and Answers

List the 3 dispersal patterns seen in nature.

Random dispersion 2) Clumped dispersion 3) Uniform dispersion

Which pattern in nature is the least frequent?

Random dispersion

Which pattern in nature is most frequent?

Clumped dispersion

List 4 factors that often influence clumped dispersion.

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List in order the hierarchical organization within ecology: population -> _ -> ecosystem -> _

community; biosphere Signup and view all the answers

Which of the above does natural selection act most directly on?

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List 2 examples of density-dependent factors that influence the size of a population.

<ol> <li>Predation 2) Disease</li> </ol> Signup and view all the answers

Define intraspecific scramble competition.

Exploitation competition or scrambled competition occurs when individuals in a population share limited resources more or less equally. Signup and view all the answers

Is scrambled competition good?

False Signup and view all the answers

What does scrambled competition make the population susceptible to?

There is a risk that the population could drop to zero Signup and view all the answers

Give an example of scrambled competition.

Moose population on Isle Royale Michigan experienced increased population leading to vegetation depletion and starvation. Signup and view all the answers

Distinguish between abiotic and biotic factors.

Abiotic factors are nonliving elements of the environment, while biotic factors are the living components. Signup and view all the answers

Distinguish between r and k selected organisms. Give an example of each.

r selection: high population growth rate (e.g., insects); k selection: traits for survival near carrying capacity (e.g., redwood trees). Signup and view all the answers

Define age structure.

The number and proportion of people at each age in a population. Signup and view all the answers

What happens to a population that has a high proportion of prereproductive individuals?

A strong population growth momentum exists. Signup and view all the answers

A human population that is shrinking would have a small proportion of _______ individuals.

pre-reproductive Signup and view all the answers

The world population has increased dramatically during the past few centuries due to what?

Younger age structure and the higher-than-replacement-level fertility rates. Signup and view all the answers

How many species must be present to make up a community?

Varies greatly in size. Signup and view all the answers

A community is made up of biotic and abiotic parts.

False Signup and view all the answers

An ecosystem is made up of biotic and abiotic parts.

True Signup and view all the answers

What is the function of producers, consumers, and decomposers in a community? Must we have all three?

Yes, they are essential for energy flow: producers capture energy, consumers utilize it, and decomposers recycle nutrients. Signup and view all the answers

Name 3 characteristics of a community.

<ol> <li>Number and types of species 2) Relative abundance of each species 3) Interactions among different species</li> </ol> Signup and view all the answers

Study Notes

Dispersal Patterns in Nature

Random dispersion occurs when individuals are spaced without regard to others, often seen in species with no specific resource needs.
Clumped dispersion, the most common pattern, is due to uneven resource distribution and social structures within species.
Uniform dispersion results in evenly spaced individuals, often resulting from competition for resources.

Ecological Hierarchical Organization

Population is the smallest organization, followed by community, then ecosystem, and finally biosphere.

Natural Selection Influence

Natural selection primarily acts on populations, shaping traits and behaviors that enhance survival and reproduction.

Density-Dependent Factors

Predation, disease, and competition are examples of factors that limit population size and reflect interdependence among species.

Intraspecific Scramble Competition

Exploitation competition occurs when individuals share limited resources equally, leading to inadequate resources and potential population declines.

Effects of Scrambled Competition

High population density can result in starvation and significant population drops, illustrated by the moose crisis on Isle Royale.

Abiotic vs. Biotic Factors

Abiotic factors refer to nonliving elements, like temperature and soil, affecting organisms; biotic factors are the living influences, such as predators and prey.

r and K Selected Organisms

r-selected species, like insects, prioritize rapid reproduction, while K-selected species, such as redwoods, focus on survival in stable environments with fewer offspring.

Age Structure and Population Growth

High proportions of prereproductive individuals indicate strong potential for population growth, as they contribute to larger future generations.

Human Population Dynamics

The dramatic rise in global population is attributed to younger age structures and fertility rates above the replacement level.

Community Composition

The size and species number within a community can vary greatly, and communities consist only of biotic factors.

Ecosystem Composition

Ecosystems include both biotic (living) and abiotic (nonliving) components, which interact to sustain life.

Roles in a Community

Producers (photosynthetic organisms), consumers (herbivores, carnivores), and decomposers (fungi, bacteria) create a balanced ecosystem, all three roles are essential.

Community Characteristics

Communities have diverse characteristics, including species richness, relative abundance, interspecies interactions, resilience to disturbances, nutrient flow, and productivity.

Fundamental vs. Realized Niche

The fundamental niche encompasses the ideal conditions a species can occupy, while the realized niche is the actual space a species occupies due to competition and other limiting factors.

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Description

This study guide contains key concepts from Biology Chapters 53, 54, and 56, focusing on dispersal patterns in nature. It covers random, clumped, and uniform dispersion, providing essential definitions and examples for better understanding. Ideal for students preparing for exams or enhancing their knowledge in ecology.