Births, deaths , immigration ( migration in) and emigration (migration out) are four factors that determine population ____.
Size
Change in population size = (births - deaths) (+ or -) (immigrants - emigrants).
+
Two opposing forces that determine birth and death rates are biotic ______ and environmental resistance.
potential
______ potential is the theoretical maximum rate at which a population could increase, assuming a maximum birth rate and minimal death rate
Biotic
_________ resistance refers to the curbs on population growth that are set by the living and nonliving environment
Examples include competition, predation, and parasitism, availability of nutrients, energy and space and natural events (storms, weather, fl
Environmental
In nature, the interaction between biotic potential and environmental resistance usually results in a _____ between size of a population and the resources available to support it.
Balance
biotic potential can produce exponential growth, evolutionarily successful organisms possess ____ that make them all adapted to their environment. They then pass these on to their offspring. If environmental resistance is reduced, populations can grow rap
Traits
The growth rate (__) or rate of the natural increase is the change in the population size per individual per unit of time.
R
Growth (r) (= or ~) birth rate(b) - death rate (d)
0
____ rate equals number of births that time period over the number of total individuals. ( 10 births/1000 ind = 0.1 birth rate)
Birth
_____ rate equals amount of deaths in that time period over the total amount
Death
Population growth (_) = r (growth rate) x N (population size)
G
If births exceed deaths by a constant percentage, population growth produces a _____,. (Exponential growth)
J-curve
A pattern of continuously accelerating increase in population size is called ______ growth. (Can cause J- curve in graph)
Exponential
Age, frequency, number of offspring, reproductive life span and death rates are several factors that _____ biotic potential
Influence
The (younger or older) the organism reproduces the more of that organisms you will have.
Younger
exponential growth cannot continue indefinitely. All populations that exhibit exponential growth must eventually stabilize or ____
Crash
Exponential growth can be observed in populations that undergo _____ and _____ cycles, in which periods of growth are followed by a sudden, massive drop. (Insects, microbes)
Boom, bust
______ populations are linked to changes in rainfall temperatures or nutrient availability, ideal conditions encourage rapid growth and massive drop off. Boom and bust cycle
Seasonal
Exponential growth occurs when environmental resistance is ______, with circumstances like food supply increasing and population- controlling factors such as predators being reduced.
Reduce
_____ species are organisms with a high biotic potential that are introduced into ecosystems where they did not evolve from and encounter very little environmental resistance. There number may explode due to lack of natural predators.
Invasive
Populations increase to the max number sustainable by their environment and then stabilize is called _____ population growth. S-curve
Logistic
The maximum population size that can be sustained by an ecosystem for an extended time without damage to the ecosystem is called its ______ capacity (K)
Carrying
When logistic growth is plotted, it results in an S-shaped growth curve or _____
S-curve
If an organism exceeds its carrying capacity it will (increase or decrease) the population tremendously.
Decrease
Logistic population growth can occur in nature when a species moves into a (new or old) habitat. As populations density increase, however individuals begin to compete for space energy and nutrients. Which can reduce reproduction rate and increase death ra
New
In nature conditions are (always or never) completely stable) so both carrying capacity and population size will vary, but environmental resistance maintains populations at or below carrying capacity
Never
Environmental resistance can be classified into two broad categories
____-independent factors, which limit populations size regardless of population density
____-dependent factors, which increase in effectiveness as the population density increases(nutrie
Density
The most important natural density-independent factors are climate and _____ which are responsible for most boom and bust cycles. Other factors include human activities like pesticides, pollutants and overhunting.
weather
Populations of organisms with a life spans more than a year have evolved adaptions that allow them to survive _____ changes. Ex mammals develop thick coats and store fat to hibernate, birds migrate, and trees and bushes emery dormancy. (Density dependent)
Seasonal
predation, parasitism, and competition, are density_____ factors that limit population growth.
Dependent
______ is defined as the interaction among individuals who attempt to use the same limited resource and this interaction limits population size in a density-repent manner. Two types interspecific( between two different) and intraspecific ( between same sp
Competition
_____ specific competion is between different species.
Inter
______specific is between the same species.
Intra
_____ competition is a free for all scramble as individuals try to beat others to a limited pool of resources.
Scramble
Many animals have evolve to ______ competitions, where social or chemical interactions determine access to resources. (Ex wolf being territorial)
Contest
As populations densities increase and competition becomes more intense, some animals react by ____ or leaving
emigrating
The ___ of a population at any given time is the result of complex interactions between density independent and dependent forms of environmental resistance.
Size
Populations exhibit different ____ distributions. Clumped, uniform and random
Spatial
Populations who live in groups exhibit ____ distributions. Some advantages are multiple eyes to look for food, movement in a group(strengths in numbers) and hunting in groups. Ex. Wolves, lions birds and fish
Clumped
Organisms with a _____ distribution maintain a relatively constant distance between individuals. (Common amount territorial animals) advantages, ensures adequate resources for each individual
Uniform
Organisms with a random distribution are ____, exhibited by individuals that do not form social groups. This only occurs when no resources are scarce. There are probably no vertebrates species that maintain this.throughout the whole year.
Rare
______ describes the pattern of survival in a population. It's has three basic patterns late-loss, constant-loss and early loss
Survivorship
Survivorship tables track ____ of organisms born at the same time throughout their lifespan, and record how many continue to survive in each succeeding year
Groups
The (x or y) axis on a survivorship table is for numbers of individuals and the (x or y) is for the increasing age category.
Y,X
____-loss populations produce convex survivorship curves meaning. There is little to no death rate in the early part of life then death rate increases later in older age. These curves are seen in animals who produce few offspring that receive substantial
Late
____-loss populations produce relatively straight lines. These individuals have an equal chance of dying at any time. Examples some bird species such as robins and gulls as well as organisms that produce asexually such as hydra and bacteria
Constant
_____-loss populations produce concave cubes due to large number of offspring or little to no parental care. Many of these organisms engage in scramble competition early in life but this who make it to adulthood have a reasonable chance to survive. Ex fis
Early
______ is the study of the changing human population. In the last few centuries human population has grown nearly an exponential growth or j shaped curve, however over the last decade human population has be growing at a constant rate.
Demography
A series of ___ have increased Earth's carrying capacity to support people. Humans have manipulated the environment to increase carrying capacity. Ex technical, agricultural and industrials and medical
Advances
_____ advances include discovery of fire, tools, weapons, shelters and protective clothing.
Technical
______ advances include domestication of plants and animals.
Agriculture
Industrial and ______ advances include fewer people to produce more food and decreases in death rate and diseases
Medical
In _____ countries, people benefit from a relatively high standard of living.(access to technology and medical care). Ex Australia, New Zealand, Japan, countries in North America and Europe
Devolved
Most of Earth' people live in ____ counties which lack technology and medical care. Ex countries in central and South America, Africa and much of Asia
Developing
The rate of population growth in counties that are now developed has changed over time in predictable stages in a pattern called demographic ______. Pre-industrial, transitional, industrial and post-industrial
Transition
In the ____-industrial stage the population was relatively small with high birth and death rates
Pre
______ stage: food production increases and health care improved, which caused death rates to fall. Birth rates remain high and increases population.
Transitional
_____ stage: Birth rates fall as contraceptives were more available and as people moved from farms to cities, where there children were less important as a source to labor
Industrial
____-industrial stage: populations are relatively stable with low birth and death rates
Post
A population will eventually stabilize if parents have just the number of children to replace themselves, called replacement level fertility (RLF) average RLF is ___
2.1
World population is distributed _____. The U.N predicts a global human population of over 9 billion and growing by the year 2050. 7.9 billion coming from developing countries
Unevenly
_____ structure predicts future population growth. Patterns include growing, stable and shrinking populations
Age
Africa is an example of an _____ population
Growing
North America is an example of an ____ population
Stable
Europe is an example of ____ population
Shrinking