BIO 141 Midterm 3 Review

Ecosystem

A biological community of interacting organisms and their physical environment.

Bottleneck effect

A change in allele frequency following a dramatic reduction in the size of a population

Genetic drift

A change in the gene pool of a population due to chance

An age pyramid with a broad base that quickly slopes up to a narrow top would be indicative of ____

A developing nation

Sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Biome

A group of ecosystems that share similar climates and typical organisms

Population

A group of individuals that belong to the same species and live in the same area

Community

A group of interdependent organisms inhabiting the same region and interacting with each other

Species

A group of similar organisms that can breed and produce fertile offspring.

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

Mutualism

A relationship between two species in which both species benefit

From an evolutionary perspective, behavior can be viewed best as:

A trait that can satisfy the three conditions required for evolution by natural selection.

Monomorphism

All individuals have the same allele for a given gene

The processes of chemical cycling would be studied mainly be ____

An ecosystem ecologist

Limiting factor

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

Biotic

living

What are the six levels of organization from least inclusive to most inclusive?

species, population, community, ecosystem, biome, biosphere "Some People Can't Easily Buy Balloons"

Darwinian fitness

the ability of an individual to survive and reproduce in its environment

Dimorphism

the instance of polymorphism in which there is a difference of form between two members of a species, as between males and females

Kin selection

the process by which evolution selects for individuals who cooperate with their relatives

What are the three main types of symbiosis?

Commensalism, mutualism, parasitism

Which theorem states that no two species competing for the exact same resources can coexist?

Competitive exclusion principle

___ selection favors organisms that have character values at one extreme of the phenotypic distribution

Directional

What is the name of the theoretical maximum rate of population growth?

Exponential

Assume that you carry an allele R, that cause you to help individuals to whom you are not related. This help increases their fitness and decreases yours. The frequency of allele R may still increase in the population:

If individuals you help are likely to return the favor and help you at some point in the future.

A sudden natural catastrophe resulting in massive die-offs would be categorized as a density-_____ factor

Independent

Why or why is it not accurate to say that individuals evolve?

It is not accurate because individuals do not change over time in a way that can be passed on to the next generation.

Carrying capacity

Largest number of individuals of a population that a environment can support

An ecosystem is a collection of all the ___ in a given area.

Living and nonliving things

Which of the following is the best way to distinguish male from female?

Males produce motile gametes

There have been several mass extinctions in the planet's history, but the current mass extinction is different. What is causing the current mass extinction?

Man's direct activities

Gene flow

Movement of alleles into or out of a population due to the migration of individuals to or from the population

What is the original source of variation?

Mutation

Difference between natural selection and evolution

Natural selection is a process by which organisms better adapted to their environment tend to survive and produce more offspring, while evolution is the change in the heritable characteristics of biological populations over successive generations.

Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes

Abiotic

Non-living

Biosphere

Part of Earth in which life exists including land, water, and air or atmosphere

What is it called when we have one female that mates with many males?

Polyandry

What is it called when we have one male that mates with many females?

Polygyny

What is the smallest unit that can evolve?

Population

Hybrid weakness. Pre or post - zygotic?

Postzygotic. Offspring of two species may be unfit, or they may be sterile

There are little birds that spend a great deal of time on the back of a rhinoceros and eat the blood sucking ticks out of the rhino's ears. The bird-tick relationship is an example of ____

Predator-prey

Behavioral isolation? Pre or post - zygotic?

Prezygotic. Form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding

Mating time differences. Pre or post - zygotic?

Prezygotic. Many species are able to reproduce only at specific times

Mechanical incompatibility. Pre or post - zygotic?

Prezygotic. Members of different species often cannot mate because their anatomies are incompatible

Habitat isolation. Pre or post - zygotic?

Prezygotic. Populations live in different habitats and do not meet

Gametic incompatibility. Pre or post - zygotic?

Prezygotic. Sperm from one species cannot fertilize eggs of another species

What are the three conditions required for evolution to occur?

Resources in the environment must be limited. Traits must be heritable. Individuals within a population must vary in their ability to compete for resources.

Resource partitioning

The division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species

"Ecology" is best defined as the study of ____

The interactions between living organisms and their environments.

Despite an abundance of habitat, why will it be difficult for the human species to recover (from a single family)?

The reduced genetic diversity will make it difficult for the population to adapt to new diseases or other environmental changes.

Sexual dimorphism refers to:

The situation in which males and females differ physically and/or behaviorally.

Why are mules considered to be a "weak hybrid"?

They are sterile

Altruistic behavior

action in which an organism helps another at its own expense

Reciprocal altruism

behavior that benefits another with the expectation that those benefits will be returned in the future

An ecosystem contains

both the living organisms and the abiotic components of the environment

Founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

Which of the following is an example of a biotic factor? Energy Temperature Bacteria Nutrients

Bacteria

What are the six main reproductive barriers?

Behavioral isolation Habitat isolation Gametic incompatibility Mating time differences Mechanical incompatibility Hybrid weakness

What are the five main mechanisms of evolution?

Genetic drift Gene flow Bottleneck effect Founder effect Sexual selection

Logistic growth

Growth pattern in which a population's growth rate slows or stops following a period of exponential growth

What are five main causes of biodiversity loss?

Habitat destruction Overharvesting Invasive species Pollution Global climate change