# Set 9 - Ecology Part 1 - My Max Score

celine's version from 2018-02-24 04:33

## Section 1

Refers to the organisms of a species that share an ecosystem.population
The number of individuals per unit areadensity
Populations differ in ____________ and ____________density, dispersion
Species may have ____________, ____________, or ____________ dispersion patterns.uniform, clumped, or random
The size of a population increases when organisms are added to the population, via ____________ or ____________.birth or immigration
The size of a population decreases when organisms are removed via ____________ or ____________.death or emigration
Distribution can be due to both ____________ and ____________ factors. biotic (living) and abiotic (physical)
What is the difference between the density and distribution of a population? The density of a population is the number of individuals per unit area. The distribution of a population is how they are arranged in the area, whether evenly spaced, all in one spot as a group, in small family units, etc.
What factors determine the size of a population? The number of births, number of deaths, immigration and emigration.
2 patterns of population growth. discrete breeding and continuous breeding
In ____________, organisms reproduce once and cease to grow as adults; they expend energy in reproduction and die. discrete breeding
In ____________, organisms reproduce throughout their lifetime, which invests energy in their future survival. continuous breeding
Population growth models predict changes in ____________ over time under particular conditions.population size
Mortality within a population is recorded in a ____________ and illustrated by a ____________.life table, survivorship curve

## Section 2

Things in the environment that are required for a particular species and that can determine their presence or absence in an area are called ________________. limiting factors
When resources are unlimited, populations exhibit exponential growth, resulting in a ____________ curve. J-shaped
When resources are limited, populations exhibit logistic growth. In logistic growth, population expansion decreases as resources become scarce. It levels off when the carrying capacity of the environment is reached, resulting in an ____________ curve.S-shaped
An ecosystem has resources to support a maximum population size for a particular species. This is called the ____________ for the ecosystem for a given population.carrying capacity (K)
The number of individuals of a particular species that an environment can support; indicated by the letter “K”carrying capacity
The ____________ of a particular environment is the maximum population size that it can support.carrying capacity
The carrying capacity acts as a moderating force in the growth rate by slowing it when resources become ____________ and stopping growth once it has been reached.limited
What is biotic potential and under what kind of population growth is it observed? Biotic potential is the maximum growth rate of a population in the perfect habitat with no limiting factors present. It is most often seen in the exponential growth of populations.
Conditions in the environment which prevent populations from attaining their biotic potentials are called ________________.environmental resistance
What type of population growth occurs in the presence of environmental resistance? logistic growth
What is carrying capacity? Carrying capacity is the maximum number of individuals of a population which can be supported in a given habitat.
Which kind of population will grow faster, one with more males than females or one with more females than males, and why?lthough all females of both populations can still obtain mates, the one with more females than males will grow faster, simply because there are more females to produce offspring.
Factors that affect population size are classified asdensity-independent factors and density-dependent factors
What are the differences between density-independent and density-dependent factors of population growth? Density-dependent factors that may limit the size of a population are those which are influenced by the number of individuals present. Disease, available shelter sites, local food availability are all density-dependent factors. Density- independent factors are those environmental conditions, like blizzards or fires, which kill individuals in the population regardless of the number present.
True or False: Population size grows in a smooth curve to the carrying capacity and then levels off and stays level. False. Populations may increase in a smooth exponential curve, but they most often overshoot carrying capacity, crash back down, increase again, etc. so that the population growth curve oscillates around carrying capacity.
The logistic population model predicts two main life history patterns. K-selection and r-selection
Distinguish between K- and r-selected speciesK-selection species are defined as those present in stable and predictable environments that produce fewer offspring, have longer gestation periods, and provide long-term care after birth. r-selected species are defined as those present in fluctuating environments that have large numbers of offspring and do not provide long-term care after birth.
What are the characteristics of a population of r-strategists?hort lifespan, many small offspring produced as early as possible, no parental care, good dispersers and colonizers.
Organisms with long life spans, slow rates of growth, and parental care of only a few young at a time are under what type of selection? K-selection
In what type of environments do r-strategists and K-strategists each do best? K-strategists tend to be specialists and live in habitats that are relatively stable, with no unpredictable or huge changes in the environment. R-strategists, as good colonizers, do well in unpredictable, fluctuating environments where they can find habitat not already occupied by a species that is a better competitor.
The study of human populations is called ____________demographics
What type of growth curve is the human population currently experiencing and what is its doubling time? The human population is currently in the upward portion of a J-shaped exponential curve. The doubling time (when the population doubles in size) is 53 years.
What is the difference in the age structure of more-developed and less-developed countries and what does this mean for future population growth in those countries? More-developed countries have similar numbers of people in each age group, with a slightly smaller number in the pre-reproductive ages. The populations of these countries will not grow and may even begin to decline. The age structure of less-developed countries is a classical pyramid with the largest majority of people in the reproductive and pre-reproductive age classes. The populations of these countries will continue to increase at a rapid rate as more and more people reach the reproductive ages.

## Section 3

A group of populations that interact with one another in the same environment. community
A ____________ is where an organism lives and reproduces in the environment. habitat
What is a niche? The niche of an organism includes everything it does, where it does them, and when it does them. Type of food, time when foraging, nest site, display sites, migration routes, where it goes to avoid predators, and when it searches for a mate are some examples of niche components.
____________ is a close relationship between members of two populations. Symbiosis
What are the major types of symbiosis and what is the effect on the organisms involved in each? Parasitism is a type of symbiosis in which one organism benefits while another is harmed. Commensalism occurs when one species benefits but the other is neither harmed nor helped. In mutualistic relationships, both species benefit from the interaction.
A relationship in which both species benefit. Often, the species “exchange” food, defense mechanisms, or shelter. Mutualism
A relationship in which one species benefits while the other remains relatively unaffected. Commensalism
A relationship in which one species (the parasite) benefits at the expense of the other (the host). Parasitism
____________ occurs when one organism (predator) feeds on another (prey). Predation
An increasing ____________ can sustain a larger predator population. In turn, the larger number of predators can ____________ the number of prey. prey population, diminish
____________, the hunting and consuming of animals by other animals, often shows cyclical patterns of predator/prey population sizes; predators increase in numbers when prey species are plentiful.Predation
____________ is the eating of plant material for energy and can assist the plants with seed distribution.Herbivory
Plants have evolved ___________ to defend against being eaten by herbivores.spines and toxins
Animals use ___________ to advertise that they are toxic; ___________ to hide from predators; or have ___________, ___________, and ___________ to protect themselves.bright colors, mimicry, spines, shells, scales
Resemblance of an organism to its surroundings for avoiding detectioncamouflage
The consumption of living plant tissue by animalsherbivory
___________ is when a non-toxic species looks similar to a poisonous one, which deters predator attacks.Batesian mimicry
the resemblance of one or more non-poisonous species to a poisonous species, for example, the scarlet king snake and the coral snakeBatesian mimicry

## Section 4

Competition Between Populations Interspecific competition & intraspecific competition
Competition between different speciesInterspecific competition
Competition between members of the same speciesintraspecific competition
Both types of competition drivenatural selection
___________ competition results when two species in an ecosystem share overlapping niches and therefore rely on the same limited set of resources. Interspecific
No two species can occupy the same niche at the same time.Competitive exclusion principle
In some cases, one or both species may evolve to occupy different niches. For example, they may evolve to feed on different food sources or to nest in different trees. This divergence in traits due to competitive exclusion is known ascharacter displacement
___________ occurs when species shift niches; they no longer directly competeResource partitioning
3 main types of species that serve as the basis for a communityfoundation species, keystone species, and invasive species
___________ are considered the “base” or “bedrock” of a community, having the greatest influence on its overall structure. They are usually the primary producers: organisms that bring most of the energy into the communityFoundation species
A ___________ is one whose presence is key to maintaining biodiversity within an ecosystem and to upholding an ecological community’s structure.keystone species (The Pisaster ochraceus, sea star is a keystone species. When this organism is removed from communities, populations of their natural prey (mussels) increase, completely altering the species composition and reducing biodiversity)
___________ are foreign species whose introduction can cause harm to the economy and the environment. Invasive species (Invasive species threaten ecosystems)
___________ species change the environment where other species live, modifying it to benefit the organisms that live there.Foundation
___________species maintain biodiversity; their removal can greatly alter the dynamics within the community.keystone
___________species are non-native organisms introduced into an area that may be better competitors and reproduce faster than native species; they tend to upset the natural balance.Invasive
any species that has been introduced to an environment where it is not native and has since become a nuisance through rapid spread and increase in numbers, often to the detriment of native speciesInvasive species
A species that exerts a large, stabilizing influence throughout an ecological community, despite its relatively small numerical abundancekeystone species