Chapter 9 Vocabulary Flashcards
population dynamics
Major abiotic and biotic factors that tend to increase or decrease the population size and age and sex composition of a species
density
number of individuals in a certain place
age distribution
the proportion of individuals of each age in a population
clumping
organisms living in groups
uniform dispersion
the individuals are spread out evenly in the environment
random dispersion
the individuals of a population are spread out in no particular pattern
immigration
Migration of people into a country or area to take up permanent residence
emigration
movement of people out of a population
prereproductive stage
Age structures are usually described in terms of organisms that are not mature enough to produce
reproductive state
age structures that are capable of reproduction
postreproductive state
age structures that are too old to reproduce
biotic potential
maximum rate at which the population of a given species can increase when there are no limits on its rate of growth
intrinsic rate of increase
rate at which a population would grow if it had unlimited resources
environmental resistance
All the limiting factors that act together to limit the growth of a population
carrying capacity
maximum population of a particular species that a given habitat can support over a given period
logistic growth
Pattern in which exponential population growth occurs when the population is small, and population growth decreases steadily with time as the population approaches the carrying capacity
exponential growth
Growth in which some quantity, such as pop. size or economic output, increases at a constant rate per unit of time (such as 2% per year)
sigmoid/S-shaped curve
a plot of the number of individuals against time causes this.
overshoot
when they exceed the carrying capacity of the environment
reproductive time lag
the period needed for the birth rate to fall and the death rate to rise in response to resource overconsumption
dieback/crash
occurs with species when they are unable to switch to a new resource or move to another area
density-independent population control
affect a populations size regardless of its density
density-dependent population control
Rely on a populations size
Stable Fluctuation
When a species who’s population size fluctuates slightly above and below its carrying capacity
irruptive fluctuation
when the population growth may occasionally explode or erupt to a high peak and then crash to a more stable lower level or in some cases a very low level
cyclic fluctuation
when a populations size will rise and fall at certain times
irregular fluctuation
have changes in their population size with no reoccurring pattern.
asexual reproduction
all offspring are exact genetic copies of a single parent. The cell can divide to produce to identical cells
sexual reproduction
organisms produce offspring by combining sex cells or gametes from both parents
r-selected species
species with a capacity for high rate of population increase
Small, many offspring
little parental care
K-selected species
Competitor species
reproduce late in life
have small number of offspring
long life span
survivorship curve
graph showing the number of survivors in different age groups for a particular species
late loss
high survivorship to a certain age, then high mortality
elephants, humans
early loss
population survivorship is low early in life
annual plants and many bony fish
constant loss
population that shows a fairly constant death rate at all ages
songbirds
founder effect
when a few individuals in a pop. colonize a new habitat that is geographically isolated from other members of the pop.
demographic bottleneck
occurs when only a few individuals in a pop. survive a catastrophic such as a fire or hurricane
genetic drift
involves random changes in the gene frequencies in a pop. that can lead to unequal reproductive success
inbreeding
when individuals in a small pop. mate with one another
increases the frequency of defective genes within a pop. and affect its longterm survival
metapopulations
collection of interacting local pop. of a species
What are the two reasons sea otters almost became extinct by the early 1900s?
overhunting for their thick and luxurious fur and because they competed with fishers for valuable abalone fish.
What are three reasons we should care about this species?
- people love to look at these charismatic, cute, and cuddly animals as they play in water
- biologists classify them as keystone species that help keep sea urchins and other kelp eating species from depleting kelp forests in offshore coastal waters. - (ethical) Some people believe it is wrong to cause their premature extinction.
What are four reasons species live in clumps?
- the resources a species needs vary greatly in availability from place to place
- living in flocks, herds, and schools can actually provide better protection from predators. -living in packs gives some predator species such as wolves, a better chance of getting food
- some animal species form temporary groups for caring for their young and mating
What are the four variables that govern changes in population size?
births, deaths, immigration, and emigration.
Population increases from birth and immigration and decreases from deaths and emigration
Write the equation for population change.
Population Change = (Births + Immigration) - (Deaths + Emigration)
What is likely to happen if an age structure diagram shows a large number of prereproductive organisms?
If it shows a large number of pre reproductive organisms, then it will increase. The organisms are in the pre reproductive stage. The size of the population’s age structure will increase if it shows a large number of pre reproductive organisms.
What is likely to happen if an age structure diagram shows a large number of postreproductive organisms?
If it shows a large number of post reproductive organisms, it will decrease. The size of the population’s age structure will decrease. The organisms are in the post reproductive stage.
What is likely to happen if an age structure diagram shows an even distribution between all three stages?
If it shows an even distribution between all three stages, it will remain constant. It will remain constant because the reproduction by younger individuals will be roughly balanced by the deaths of older individuals.
What are the four characteristics of individuals in populations with a high rate of growth?
- reproduce early in life
- have short generation times
- can reproduce many times
- have many offspring each time they reproduce.
What are five limiting factors that could keep a population from growing indefinitely?
light, space, water, or nutrients, or by too many competitors or predators
What two factors determine carrying capacity (K)?
Two factors that determine carrying capacity (K) are biotic potential and environmental resistance.
What happens in exponential growth? Why does this happen?
In exponential growth, a population grows at a fixed rate such as 1% or 2%. It starts slowly but begins to grow faster as the population increases because the base size of the population is growing.
What happens in logistic growth? Why does this happen?
In logistic growth, a rapid exponential population growth is followed by a steady decrease in population growth with time until the population is levels off. This occurs because the population encounters environmental resistance and its rate of growth decreases as it approaches the carrying capacity of its environment.
What events cause the sigmoid (S-shaped) population growth curve?
The events that cause the sigmoid (S-Shaped) population growth curve are a plot of the number of individuals against time.
Give two examples of population overshoot and dieback.
Two examples of population overshot and dieback are the sheep and the reindeer. These two species experienced overshot and dieback on their population size.
What factors are density independent?
floods, hurricanes, unseasonable weather, fire, habitat destruction, pesticide spraying, and pollution.
What factors are density dependent?
competition for resources, predation, parasitism, and infectious diseases.
What are the three disadvantages of sexual reproduction?
- male do not give birth
- increased chance of genetic errors and defects during the splitting and recombination of chromosomes
- courtship and mating rituals consume time and energy
- can transmit disease
- can inflict injury on males of some species as they compete for sexual partners.
Considering the disadvantages of sexual reproduction, why do 97% of Earth’s species use it?
it provides a greater genetic diversity in offspring and males of some species can gather food for the female and the young and protect and help train the young.
Give characteristics and examples of r-selected species.
- reproducing early
- putting most of their energy into reproduction
- examples are bacteria, rodents, most insects, algae, and annual plants.
Give characteristics and examples of K-selected species.
- reproducing late in life
- having a small number of offspring with fairly long lifespans
- develop inside their mothers and are born fairly large
- mature slowly
- cored for and protected by one or both parents until they reach reproductive age
- do well in competitive situations and they follow a logistic growth curve
- examples are elephants, whales, humans, birds of prey, and large long-lived plants.
Explain the four factors that play a role in the loss of genetic diversity and the survival of such populations.
founder effect, the demographic bottleneck, genetic drift, and inbreeding.
List the nine human impacts on natural systems.
- )reducing biodiversity by destroying, fragmenting, and degrading wildlife habitats
- ) reducing biodiversity by simplifying and homogenizing natural ecosystems
- )using, wasting, or destroying an increasing percentage of the earth’s net primary productivity that supports all consumer species
- )strengthening some populations of pest species and disease causing bacteria
- )eliminating some predators.
- )we have deliberately or accidentally introduced new or nonnative species into ecosystems
- )we have over harvested some renewable resources and the eight way is we interfere with the normal chemical cycling and energy flows in ecosystems
- )we have over harvested some renewable resources and the eight way is we interfere with the normal chemical cycling and energy flows in ecosystems
What are the two major challenges humans face?
1 we need to maintain a balance between simplified, human-altered ecosystems and the more complex natural ecosystems on which we and other species depend.
2 we need to slow down the rates at which we are altering nature for our purposes.
REVIEW NOTES AND DIAGRAMS
REVIEW NOTES AND DIAGRAMS
Intrinsic Growth Rate
Under ideal conditions, with unlimited resources, the maximum potential for growth
Exponential growth looks like what shape?
J
J-shaped curve
Looks like a j when graphed
Logistic growth
when a population whose growth is initially exponential, but slows as the population approaches the carrying capacity
Logistic growth and s shaped curve look like what shape?
S on a graph
Who is Georgii Gauss and what is his principle?
Russian biologist, 1910-1986
principle- species competing for the same limited source cannot co-exist
