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Biology 12 > Unit 5 (ISU) > Flashcards

Unit 5 (ISU) Flashcards

1
Q

population size (N)

A

the number of individuals of the same species living within a specific geographical area

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2
Q

population density (Dp)

A

the number of individuals per unit of volume or area

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3
Q

counting each individual within a population is impractical. how do ecologists use other methods to estimate population size and density? (in general)

A

sampling several smaller areas and applying the results to an entire area occupied by a species

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4
Q

transect

A

a long, relatively narrow rectangular area or line used for sampling a population
researchers choose a line of specific length, randomly determine a starting point and the direction they will travel. the researcher walks its length, counting the species being monitored and records individuals within a certain distance of the transect line
useful when density of a species is low, or when individual organisms are large, ex. trees

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5
Q

quadrat

A

an area of specific size used for sampling a population; often used to sample immobile organisms or those that move very little
several sample sites are randomly chosen and quadrats of a known size are marked. the number of individuals within the boundaries is counted
useful for sampling plant populations and those of sessile animals
to determine population density, calculate the sum of individuals in quadrats and divide by total area of quadrats
size of population can be estimated by extrapolating the density to the entire study area

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6
Q

quadrat population density equation

A

Dp=N(sum of individuals in quadrats)/A (area of quadrats)

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7
Q

mark-recapture

A

a method in which animals are captured, marked with a tag, collar, or band, released, then recaptured at a later time to determine an estimate of population size
useful for highly mobile populations, such as fish or birds

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8
Q

mark-recapture population size equation

A

N=(# of originally marked)(total individuals in recapture)/marked individuals in recapture

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9
Q

distribution pattern

A

the pattern in which a population is distributed or spread in an area; three types are uniform, random and clumped

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10
Q

two main factors that influence distribution patterns

A

the distribution of resources such as food and water within a habitat
the interactions among members of a population or community

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11
Q

clumped distribution

A

results from the tendency for populations to gather near unevenly distributed resources ex. animals gather near a water source, and plants cluster in locations with optimal moisture, temp and soil conditions
common among species in which individuals gather into groups for positive interactions (ex. protection from predators; increase hunting efficiency)

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12
Q

uniform distribution

A

exhibited in situations where resources are evenly distributed but scarce, and is often a consequence of competition between individuals
can be seen in plants competing for resources as well as in birds of prey and other organisms that behave territorially to defend food and shelter needed for survival, mating, or raising young
usually a result of negative interactions among population members (in contrast to clumped distribution)

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13
Q

random distribution

A

exhibited if resources are plentiful and uniformly distributed across an area because there is no need for individuals to defend their share
requires that interactions between individuals are neutral

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14
Q

distribution patterns displayed by a population are ____ and can _____ with the passing seasons or even over the course of a day

A

fluid, change

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15
Q

what forms distribution patterns

A

complex interactions between behaviors and other characteristics that increase each individual’s chances of reproduction and survival; ex. seasons changing and life stages in organisms

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16
Q

life history

A

the survivorship and reproductive patterns shown by individuals in a population
include the age at which an organism is sexually mature (when it can reproduce), how often it reproduces, how many offspring it has at a time, and life span

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17
Q

two main measures to describe life history

A

fecundity and survivorship

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18
Q

fecundity

A

the average number of offspring produced by a female member of a population over her lifetime
affected by age at which an organism becomes sexually mature
the # of offspring tends to be inversely related to the amount of care parents provide

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19
Q

survivorship

A

the number or percentage of organisms that typically live to a given age in a given population
ecologists study survivorship by studying a large group of individuals all born at the same time, monitoring the group over its lifetime, and recording the age of death for each organism

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20
Q

3 general patterns of survivorship

A

type III: most individuals die as juveniles (perhaps even before they sprout, hatch or are born). only few live to produce offspring or to old age. however, they can produce large #s of offspring. ex. oysters, many insects, plants, invertebrate organisms
type I: opposite of type III. high rate of juvenile survival, individuals live until sexual maturity and beyond. ex. humans, most mammals
type II: lies between I and III. risk of mortality is constant through an individuals lifetime

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21
Q

immigration

A

the movement of individuals into a population

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22
Q

emigration

A

the movement of individuals out of a population

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23
Q

in most population, immigration and emigration are roughly ______. ecologists tend to focus only on _____ and ______ when considering how populations size changes.

A

equal, birth, death

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24
Q

change in population size equation

A

deltaN=B(# of births)-D(# of deaths)

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25
Q

population change with immigration and emigration equation

A

deltaN=[B+I]-[D+E]

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26
Q

rate of population growth equation

A

gr (growth rate) = delta N/delta T

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27
Q

benefits of measuring growth rate

A

useful for populations that are expanding quickly, and for populations that may be endangered
can help ecologists make management decisions

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28
Q

growth rate does not take into consideration how the initial size of the population may affect population growth. explain

A

as long as nothing limits it, the growth of a larger population will always be greater than that of a smaller population, since this population typically has more individuals that can reproduce

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29
Q

capita growth rate equation

A

cgr=deltaN(# of individuals)/N (original # of individuals)

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30
Q

biotic potential

A

the highest possible per capita growth rate for a population

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31
Q

the factors that determine a species biotic potential are all related to its fecundity and include

A

the # of offspring per reproductive cycle
the # of offspring that survive long enough to reproduce
the age of reproductive maturity
the # of times the individuals reproduce in a life span
the life span of the individuals

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32
Q

exponential growth

A

the growth pattern exhibited by a population growing at its biotic potential

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33
Q

why can’t a population grow at its biotic potential

A

resources will quickly become limited. eventually, members of the population will compete for resources and the growth rate will slow

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34
Q

carrying capacity

A

maximum population size that a habitat can sustain over an extended period of time

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35
Q

logistic growth

A

the growth pattern exhibited by a population for which growth is limited by carrying capacity, or limited availability of resources

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36
Q

what happens as a population starts to grow in size

A

limiting factors such as disease, predation, and competition for resources reduce the amount of energy that is available for reproduction. this causes the growth rate of the population to decrease

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37
Q

why is carrying capacity not a static condition

A

it changes as the population responds to changing conditions such as a decreasing oxygen supply in a pond, low food supply during winter, disease, predation and limited space

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38
Q

what are life strategies

A

strategies to maximize the number of offspring that survive to a reproductive age
r and k
most populations are somewhere between the two groups. properly describing whether a population uses an r- or K- selected life strategy requires that it be compared to another population

39
Q

r-selected strategies

A

life strategies used by populations that live close to their biotic potential
in general, species that have an r-selected strategy:
-have a short life span
-become sexually mature at a young age
-produce large broods of offspring
-provide little or no parental care to their offspring
ex. insects, annual plants and algae
they take advantage of favourable environmental conditions, such as the availability of food, sunlight and warm temp. to reproduce quickly.
they experience exponential growth during the summer, but die in large numbers at the end of the season

40
Q

K-selected strategy

A

life strategies used by populations that live close to the carrying capacity of their environment
in general, species that have a K-selected strategy:
-have a relatively long life span
-become sexually mature later in life
-produce few offspring per reproductive cycle
-provide a high level of parental care
ex. mammals and birds

41
Q

density-independent factor

A

an abiotic event that affects population growth in the same way, regardless of population density. ex. weather, floods and droughts, forest fires, hurricanes, and tornadoes

42
Q

density-dependent factor

A

a biotic interaction that varies in its effect on population growth, depending on the density of the populations involved. ex. competition or predation

43
Q

intraspecific competition

A

a situation in which members of the same population compete for resources

44
Q

interspecific competition

A

a situation in which two or more populations compete for limited resources
driving force for evolutionary change

45
Q

in competing species, individuals that are most _______ from their competitors will be best able to avoid competitive interactions and will therefor obtain the most resources

A

different

46
Q

how do producer-consumer and predator-prey relationships put selective pressure on both parties

A

the more successful predators and consumers drive the natural selection of the produces and prey

47
Q

example of how the scarcity of a producer or prey species will limit the growth of a consumer or predator species’ population

A

trees have a direct relationship with birds and beavers

48
Q

population cycles

A

alternating periods of large and small population sizes

49
Q

sinusoidal growth

A

a wave like oscillating growth patterns that is typical of predator-prey interactions

50
Q

protective colouration

A

adaptations that help individuals avoid predation; includes camoflauge, mimicry, and body colouration used as a warning signal

51
Q

symbiosis

A

an ecological relationship between two species living in direct contact; includes parasitism, mutualism, and commensalism

52
Q

parasitism

A

a symbiotic relationship in which a symbiont lives off and harms the host. ex. insects, viruses, unicellular organisms, various types of worms
parasite-host cycles are similar to predator-prey cycles

53
Q

mutualism

A

a type of symbiotic relationship in which both species benefit from the relationship
both partners co-evolve. growth in one population typically spurs growth in the other population

54
Q

commensalism

A

a symbiotic relationship in which one partner benefits and the other partner neither benefits nor is harmed

55
Q

demography

A

the study of statistics related to human populations, such as population size, density, distribution, movement, births and deaths

56
Q

factors that allowed humans to increase the carrying capacity of their environment and change from a logistic to exponential growth pattern

A
  • increased food supply by improved agricultural methods and domestication of animals
  • breakthroughs in medicine, cured once-fatal illnesses
  • better shelter, protection from weather
  • food storage capacity improvements
57
Q

doubling time

A

the time it takes for a population to double in number

58
Q

population pyramid

A

a type of bar graph that shows the age distribution in a population, which demographers use to study a population
shape of a population pyramid is used to predict demographic trends in the population

59
Q

what do different shapes of population pyramids predict

A

triangular - predicts a future of explosive growth because a large portion of the population will enter their reproductive years at the same time
rectange - stable
inverted triangle - shrinking

60
Q

humans have been able to _______ the carrying capacity of Earth, and the population continues to grow exponentially. However, all environments have a ______ and there is _______ to suggest that Earth is no exception

A

increase, limit, no evidence

61
Q

ecological footprint

A

the amount of productive land that is required for each person in a defined area, such as a country, for food, water, transportation, housing, waste management, and other requirements

62
Q

six major categories of deman

A

cropland, grazing land, fishing groups, forest land, carbon absorption land, and building area

63
Q

largest component of carbon footprints for developed countries (ex. Canada and USA)

A

land for energy production, food production, and forestry

64
Q

available biocapacity

A

earth’s carrying capacity for the human population
low-productivity areas such as arid regions and open oceans, are not considered biologically productive areas in this calculation. it is estimated that about 1/4 of Earth’s surface constitutes Earth’s biocapacity

65
Q

costs of the growing human population and challenges to manage growth and resources

A

demand for energy, greater need for food, need for adequate waste disposal, decline in biodiversity

66
Q

the greatest human-produced source of mercury emissions. what dangerous element is found in coal

A

coal-burning power plants

mercury

67
Q

how does mercury enter ecosystems

A

when mercury enters the atmosphere, it quickly enters waterways, either settling directly into lakes and streams, or washing into them after being deposited on land. once in water, certain micro-organisms convert mercury into methylmercury. living organisms easily absorb this highly toxic form of the metal. methylmercury quickly biomagnifies up the food chain to the higher-level consumers, including humans who eat fish and shellfish.

68
Q

biomagnification

A

the increase in concentration of a substance, such as methylmercury or DDT, that occurs in a food chain and is not broken down by environmental processes

69
Q

how does mercury affect ecosystems and organisms

A

when methylmercury reaches high enough levels in animals, the chemical typically interferes with growth, development, and reproduction. harm to the nervous system may result in abnormal behavior and eventual death. chronic exposure in humans damages the kidneys, liver, and lungs, as well as the immune and nervous systems. in pregnant women, it interferes with the brain development of the fetus. in young children, high levels may interfere with brain development and the ability to learn

70
Q

how can we reduce the amount of pollutants released into the atmosphere

A

replacing fossil fuels such as coal and natural gas with renewable forms of energy

71
Q

where is the need for food the greatest

A

where population growth and poverty are greatest

72
Q

deforestation

A

the cutting, clearing, or removal of trees so land can be used as pastureland or cropland
populations in poverty cut down forests to clear space for growing subsistence crops to feed rapidly growing populations and to make charcoal to sell for fuel to people in urban centres

73
Q

tropical rainforests are among the most productive ecosystems in the world. however, the soil in this ecosystem is extremely poor. explain why the poor soil does not support life

A

few nutrients ever reach the soil. instead, the nutrients and water needed by organisms in the rainforest are recycled within these biotic components. in addition, abundant rainfalls in these ecosystems result in erosion in areas that are cleared of trees, especially slopes. subsequently, mudslides can carry both soil and vegetation into waterways

74
Q

explain how the consequences of soil erosion have been catastrophic for places like Haiti and Madagascar

A

thousands of tonnes of soil are washed away. poverty in these nations often means people have no choice but to clear land

75
Q

sustainable

A

the use of resources, such as food, energy, timber and other items acquired from the environment, at a level that does not exhaust the supply or cause ecological damage

76
Q

how can deforestation be combatted

A

planting trees, terracing hills to stop erosion and prevent mudslides and landslides during the rainy season

77
Q

bycatch

A

aquatic organisms that are caught unintentionally by fishing gear or nets and often are discarded as waste

78
Q

how have demands on global fisheries harmed the environment

A

advances in technology have brought with them destructive fishing techniques that remove nearly all animal life from the sea floor

79
Q

sources of marine debris

A

cargo and passenger ships, oil platforms, and runoff from rivers

80
Q

why is plastic the most dangerous of all the forms of waste found in the sea

A

takes years to decay

ultimately finds its way into or onto marine organisms

81
Q

how does the consumption affect organisms (ex. nurdles)

A

plastic pellets called nurdles are easily consumed by marine life. plastics contain chemicals that mimic estrogen. an overabundance of estrogen has been shown to disrupt the endocrine system of organisms, to lead to the feminization of males, and to cause reproductive problems. plastics also attract and concentrate toxins such as mercury and pesticides

82
Q

one way to reduce waste

A

recycling materials and manufacturing and purchasing items that have a long life (as well as having reusable/recyclable components)

83
Q

biodiversity

A

encompasses species diversity (the variety of plants, animals and other organisms on Earth), the genetic diversity that exists within each species, and the diversity of ecosystems (ecosystem diversity) to which these species belong

84
Q

how does biodiversity stabilize ecosystems

A

making them more resilient to change and degradation
change can be natural disasters such as drought and flood or human-caused events such as oil spills and acid rain
ex. monoculture crops are vulnerable

85
Q

why is ecosystem stability essential to the survival of our species (examples)

A

wetland ecosystems filter and purify the water we drink
marine forest ecosystems take up atmospheric carbon dioxide which helps regulate our climate
other ecosystems provide us with materials to build shelters, food resources, and even medicine

86
Q

habitat loss in deforestation as a threat to biodiversity

A

organisms lose home and migrate or die
organisms reliant on dead organisms also die
competition in old and new habitat increase and more deaths occur

87
Q

habitat loss in habitat fragmentation as a threat to biodiversity

A

roads, dams, water diversions are built and habitats are cut into pieces/fragments
fragments limit interactions among populations, restrict movements of large animals that need large areas to find food and mates, and make it difficult or impossible for migratory species to complete their migrations

88
Q

habitat loss in habitat degradation as a threat to biodiversity

A

pollution can completely destroy habitats, and invasive species can out-compete native species to the point of eliminating them from the habitat

89
Q

overexploitation

A

the excessive harvesting or killing of a species until it no longer exists or is reduced to a very small population

90
Q

risks of overexploitation

A

extinction of a species, which is the disappearance of all members of a species from Earth
reduction of a population below the minimum viable population size, which is the lowest number of individuals that can persist in an environment for a long period of time without the species going extinct

91
Q

what happens when a population goes below the minimum viable population size

A

individuals might have trouble finding mates. the population’s genetic diversity will be low and inbreeding will occur, producing weakened or abnormal offspring. in this situation, genetic diversity might be too low for individuals to adapt to changing conditions

92
Q

what are invasive species and how do they threaten biodiversity

A

non-native species that relocate to an area and out compete the native species for resources
because invasive species usually do not have predators in their new environments, they reproduce in large numbers

93
Q

how do pollutants threaten biodiversity

A

by reducing the number of individuals in a population which can lead to a species extinction ex. methylmercury, DDT

Biology 12 (5 decks)

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