Exam 3 review Flashcards
1
Q
How is population defined?
A
a group of organisms of the same species that live in the same area and can interbreed with each other
2
Q
What is carrying capacity?
A
number of organisms that an ecosystem can sustainably support
3
Q
What happens to a population growth rate when the # in the population starts to or reaches carrying capacity?
A
slows down and eventually levels off
4
Q
What is environmental resistance?
A
the factors in an ecosystem that limit the growth of a population
5
Q
How does envir. resistance relate to carrying capacity?
A
Environmental resistance limits the number of individuals that survive and leads to the establishment of a carrying capacity
6
Q
term r
A
population growth rate/intrinsic rate of increase
6
Q
term K
A
carrying capacity
7
Q
How do the terms r & K relate to the exponential and logistic growth curves?
A
r (intrinsic growth rate): Determines how fast a population grows; used in exponential and logistic growth.
K (carrying capacity): The maximum population size an environment can support; used in logistic growth only.
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8
Q
Describe the exponential growth pattern of a population.
A
a population’s per capita (per individual) growth rate stays the same regardless of population size
8
Q
How is this depicted on a graph of growth rate over time?
A
a positive growth rate is shown by an increasing line, while a decreasing line indicates a negative growth rate
9
Q
If population # are at carrying capacity for a specific habitat, what would happen to the growth rate if the population was significantly reduced to below the carrying capacity?
A
initially increase
10
Q
What are the factors that influence the logistic growth rate of a population?
A
-competition for resources
-predation
-disease
-carrying capacity
-natural disaster
-extreme weather
11
Q
How do you calculate the # of idv. added to a population given a specific growth rate?
A
Initial Population x Growth Rate
12
Q
What is occuring with a population if the growth rate is positive?
A
population is increasing in size
13
Q
If a population if the growth rate is positive, Is it increasing or decreasing in size?
A
increasing in size
14
Q
If the growth rate is negative , is the population increasing or decreasing in size?
A
decreasing in size
15
Q
Iteroparous
A
a reproductive strategy characterized by multiple reproductive cycles over the course of a lifetime
16
Q
Seasonal iteroparity
A
a reproductive strategy where organisms, have specific breeding seasons throughout their lives, rather than reproducing continuously
17
Q
Continuous interoparity
A
a reproductive strategy where organisms, like humans, reproduce multiple times throughout their lives, with no specific breeding season
18
Q
How do these types of life history strategies relate to r and k-selected species?
A
relate to how organisms grow, reproduce, and survive
18
Q
Semelparity
A
a reproductive strategy where an organism reproduces only once in its lifetime and then dies
19
Q
How do these strategies determine the # of offspring that are produced by an idv.?
A
r: produce high
K: produce low
20
Q
What has the general growth pattern of Humans been?
A
logistic
21
Q
What are different methods used to determine the sizes of population?
A
direct counting
sampling techniques
mark-recapture method
indirect indicators
aerial surveys
21
Example of density-dependent factors that control populations
competition
predation
social stress
22
What are density-dependent population control factors?
disease, competition, and predation
22
What are the different types of distribution patterns seen for populations?
uniform, random, or clumped
23
What factors influence uniform distribution patterns?
competition
territorial behavior
allelopathy (in plants)
human activity
24
What factors influence clumped distribution patterns?
resource availability
social behavior
reproductive strategies
envir. conditions
protection from predators
25
How does availability of resources influence the type of distribution patterns seen for diff. populations?
clumped resources=clumped
even resources+competition=unifrom
abundant, evenly spread resources=random
26
What are survivorship curves and what do they tell you about a species life history?
graphs that show the proportion of a population that survives from one age to the next
27
Age pyramids
a graphical representation that shows the distribution of a population by age groups and sex.
28
What can age pyramids tell you about the characteristic of the countries they represent?
growth rate
life expectancy and healthcare
economic development
social/political challenges
29
What would a developed nation's age pyramid look like?
narrow base/wider middle/widening top
30
What does a developed nation's age pyramid look like?
thick base
thinner middle and top
31
Describe how developed nations have different health outcomes than pre-industrialized countries
life expectancy
cause of death
access to healthcare
sanitation and vaccination
32
What factors influence life expectancy in developed nations and pre-industrialized nations?
healthcare access
sanitation
nutrition/food security
education/awareness
33
Characteristics of K-selected species
large body size
long lifespan
few offspring
high parental care
live in a stable enviro.
34
Characteristics of r-selected species
rapid reproduction
minimal parental care
high juvenile mortality
live in unstable enviro.
35
Example of r-selected species
insect, bacteria, rodents
36
Example of K-selected species
elephants, human whales, oak tree
37
Ecological footprint
a method that determines how dependent humans are on natural resources
38
How does the ecological footprint of developed nations compared to less developed nations?
higher consumption of resources
39
What does the ecological footprint of the US look like?
high carbon footprint
high resource consumption
food footprint
40
Abiotic components of an ecosystem
temperature, light, water
41
Biotic components of an ecosystem
animals, plants, microorganism
42
What is ecosystem composed of
abiotic and biotic components
42
Ecosystem
a biological community of interacting organisms and their physical environment.
43
NIche
describes the role an organism plays in a community
44
Fundamental niche
the entire set of conditions under which an animal (population, species) can survive and reproduce itself
45
realized niche
the set of conditions actually used by given animal (pop, species), after interactions with other species (predation and especially competition) have been taken into account.
46
mullerian mimicry
when two or more species that are harmful to eat look alike so as to ward off their common predators as a whole
47
batesia mimicry
harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both
48
example of mullerian mimicry
velvet ants
49
example of batesia mimicry
harmless scarlet king snake mimics color pattern of coral snake
50
competitive exclusion principle
two species cannot coexist indefinitely in the same ecological niche if they both rely on the same limited resources
51
what occurs when 2 species occupy the same niche?
compete for the same resources
52
how does the level of disturbance affect species diversity?
affects the # of species and competition
53
Why is it important to have an ecosystem that has a high amount of biodiversity?
ecosystem resillence
food security
disease prevention
54
Different types of competition
exploitation
interference
interspecific
intraspecific
55
Is competition btw species or idv. of the same species a positive species interaction or is it negative?
negative
56
exploitation competition and ex
faster than their competitors
ex. able to extract water and nutrients from the soil faster than surrounding species.
57
interference competition and ex
When one organism physically restricts another organism's access to resources
ex. male-male competition
58
interspecific competition and ex
where different species in the same ecological area compete for the same limited resources
59
intraspecific competition and ex.
an interaction in population ecology, whereby members of the same species compete for limited resources
60
Ammensalism and ex
biological interaction where one organism is harmed or inhibited, while the other is unaffected
ex. a stampede of animals trampling over a field of plants
61
What does resource partitioning do for species that share the same territory?
reduces competition and allows for greater biodiversity
62
commensalism and ex
a symbiotic relationship where one organism benefits, and the other is neither helped nor harmed.
ex. small birds and large grazing herbivores
63
Resource portioning
when different organisms within one ecosystem split up an area so that they will not compete for the same resources and when those organisms have a special adaptation
64
How does resource portioning take effect?
individuals of different species compete less with one another than individuals of the same species
65
What benefits does resources partitioning have for populations of species that use similar resources in the same habitat?
reduces direct competition
promotes specialization
66
Character displacement
an evolutionary change that occurs when two similar species inhabit the same environment
67
How does character displacement affect competition btw species?
lessen resource competition between species
68
What type of species interaction is mutalism?
mutual benefit
symbiotic nature
69
Facultative mutalism
both species benefit from the interaction, but their interaction is not essential for their survival.
70
Parasitism
a relationship between the two living species in which one organism is benefitted at the expense of the other
71
Obligatory mutualism
one organism cannot survive without the other
72
Food web
diagram that shows how organisms in an ecosystem are connected by feeding relationships.
73
What are the different trophic levels that make up a food web?
lv1 producers
lv2 primary consumers
lv3 secondary consumers
lv4 tertiary consumers
apex predators decomposer
74
What is the energy exchange that occurs between trophic levels?
About 10% of energy is passed to the next level; 90% is lost as heat, waste, or used for life processes.
75
Primary productvively
rate at which organisms, primarily plants and algae, convert inorganic compounds into organic matter through photosynthesis or chemosynthesis, forming the base of food chains.
76
What types of organisms are considered primary producers?
oxygenic phototrophs
77
key characteristics of autotroph
Make their own food
Use sunlight (photosynthesis) or chemicals (chemosynthesis)
Base of the food chain
Include plants, algae, some bacteria
78
key characteristics of heterotrophs
Cannot make their own food
Consume other organisms for energy
Includes animals, fungi, some bacteria & protists
79
Role do decomposer and detritivores play in ecosystems and food web?
recycling nutrients and energy through the breakdown of dead organic matter
80
What type of species interaction is predation?
One species benefits, but the other is harmed
81
Diff. types of predator defenses pretty have developed to avoid being eaten?
mechanical, chemical, physical, or behavioral
82
Examples of each defense
m: porcupine's quills
c: skunks
b: playind dead
p: chameleon blending in
83
What role do keystone species play in the ecosystem?
helps hold the system together
84
What happens to an ecosystem when keystone species is removed?
Causes collapse
85
Are there any examples of re-introducing keystone predators to an ecosystem? What were the results?
Gray wolves were reintroduced to Yellowstone in 1995 after being gone for ~70 years.
greater biodiversity and ecosystem balance
86
Biomagnification
process by which pollutants increase in concentration as they move up the food chain
87
bioaccumulation
the gradual accumulation of substances, such as pesticides or other chemicals, in an organism
88
How do chemical pollutants move through the food web? what characteristics?
Pollutants bioaccumulate in organisms over time
Biomagnify up the food chain (higher levels = more toxins)
Affect top predators the most
Often fat-soluble, persistent chemicals
89
Is biodiversity equally distributed around the globe
No
90
Where is most biodiversity found?
Tropical rain forest
91
What factors influences the distribution of biodiversity across the globe?
pollution
water
soil
92
What are biodiversity hotspots?
Regions with exceptionally high species diversity
Many endemic species (found nowhere else)
Often threatened by human activity
93
Why are most hot spots located in the tropics?
Warm, stable climate year-round ☀️
High primary productivity (lots of plant growth) 🌿
More niches and less seasonal change
Long periods without major disturbances = more time for species to evolve 🧬
94
How does the level of distrbuance influence biodiversity numbers?
At high disturbance frequencies, only early-succession "weedy" species survive, leading to lower diversity
95
Why should we care about maintaing biodiversity?
food security
climate regulation
resource provision
96
exotic/invasive species
non-native organisms that are introduced into a new environment
97
how are exotic species introduce to new areas?
Accidentally
Intentionally
Escapes from captivity or cultivation
Travel & trade
98
What advantage do exotic species have when they are introduced to a new habitat?
Lack of natural predators or diseases
Outcompete native species for food, space, or resources
Fast reproduction or growth
99
What are conservation management strategies that can be used to reduce the impact of human developed on ecosystems?
Protected areas
Habitat restoration
Wildlife corridors
100
How can urban planner develop neighborhoods and the other developements with the least impact on ecosystem?
Preserve natural areas & green spaces
Use eco-friendly building materials
Build around existing habitats to avoid fragmentation 🐿️
Create wildlife corridors and buffer zones
101
How can developments minimize fragmentation?
protecting existing patches of high-quality habitat within them
102
Habitat fragmentation
when a large area of land is divided into smaller, isolated pieces.
103
Explain how fragmentation occurs, and why it is
detrimental to biodiversity, and discuss ways developers, urban planners, and
conservation organizations can mitigate the effects of fragmentation
Fragmentation occurs when large, continuous habitats are broken into smaller, isolated patches
-isolates species
-wildlife corridors
104
Minimum Viable population size?
smallest number of individuals in a species that can persist in the wild with a certain level of probability over a specified timeframe
105
How does fragmentation influence the effective population size required to maintain a genetically diverse population?
Fragmentation reduces effective population size by isolating groups and limiting breeding.
106
What happens to the population of a species if the effective population size is too low?
Inbreeding increases
Reduced genetic diversity
Increased risk of extinction
107
How does exploitation/overharvesting affect species?
lead to resource destruction
108
How does overharvesting affect economic sectors across the world?
leading to potential food crises, job losses, and a decline in biodiversity.
109
What are the effects of overharvesting commercial fisheries and timber?
Fisheries:
-Population decline of fish species
-Disruption of marine ecosystems and food webs
Timber:
-Deforestation
-Soil degradation and increased erosion
110
How does climate change affect the phenology of plant and animal species?
Earlier flowering or reproduction
Mismatched timing
Shifting migration patterns in animals (e.g., birds, butterflies) 🦅
Altered pollination patterns
111
What happens if the peak season of a food source is out of sync with the peak season
of the arrival of animals that feed on them?
Food scarcity
Reduced survival and reproduction rates
Disrupted migration patterns or altered behavior
population declines
112
Are there any examples of exploitation causing a species to go extinct?
passenger pigeons, black rhinos
113
How does Acid rain form?
a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air
114
What is the cause of acid rain and how does it travel across the country?
when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents
wind,
115
Where does acid rain have its biggest effect geographically?
116
?What effect does acid rain have on ecosystems
downwind of major industrial areas --> northeastern United States
117
flagship species
a species selected to act as an ambassador, icon or symbol for a defined habitat, issue, campaign or environmental cause
118
What role do flagship species play in conservation efforts?
raise awareness and funding for broader conservation efforts.
119
Umbrella species
species selected for making conservation-related decisions
120
What role do umbrella species play in conservation efforts?
safeguarding their large habitat needs
121
indicator species?
any species that reflects the condition of its environment
122
What role do indicator species play in conservation efforts
identify environmental threats early and informs conservation actions
123
endemic species
those that live in a limited area
124
What role do endemic species play in conservation efforts
protection of unique ecosystems and biodiversity hotspots.
125
What are the leading causes of extinction?
habitat destruction
climate change
overharvesting
126
What is the primary cause of extinction?
habitat loss
127
What has caused the increase in the average global temperatures over the last 50
years?
greenhouse gases
128
What types of gases are involved in climate change and the greenhouse effect?
carbon dioxide (CO2) methane(CH4) nitrous oxide (N2O)
129
Is the greenhouse effect a natural phenomenon?
yes
130
, have humans caused a change
in this? If so, how have we caused this change?
yes, burning fossil fuels, industrial processes, agriculture
131
eutrophication
where a water body receives excessive amounts of nutrients, leading to overgrowth of plants and algae, and potentially harming aquatic life.
132
leading causes of eutrophication process
urban runoff
industrial discharges
agricultural/excessive nutrient runoff
133
What factors have contributed to the occurrence of algal blooms in our waterways?
Nutrient pollution
Warm water temperatures🌡️🌊
Stagnant water
Sunlight
Climate change
Altered land us
134
In particular, what has contributed to the increase of HABs (Harmful algal blooms)?
excessive nutrients, changing climate conditions, and human activities.
135
What is an HAB?
Harmful algal bloom
136
How are “dead zones” in the Gulf of Mexico created?
Excess nutrients (nitrogen & phosphorus) from farm runoff and sewage cause algal blooms. When algae die and decompose, oxygen is used up, creating low-oxygen zones where marine life can't survive
137
What are “dead zones” and what
effect do they have on local wildlife?
low-oxygen (hypoxic) areas in water where most marine life can't survive.
138
What factors lead to a species being more vulnerable to extinction compared to other
species?
Small population size
Limited geographic range
Specialized habitat or diet
Low reproductive rate
High sensitivity to human activity
Poor dispersal ability
139
Explain what ecosystem services are and how they can help improve the quality of
ecosystems
clean air and water to pollination and flood control
140
How do various ecosystem services help benefit humans?
provisioning services-timber
regulating services-pollution
cultural services-tourism
supporting service-soil formation
141
Provide examples of various ecosystem services and the role they play in increasing the
quality of abiotic components of ecosystems
Water purification (Regulating) – Wetlands filter pollutants
Air purification (Regulating) – Forests absorb CO₂
Soil formation (Supporting) – Decomposers break down organic matter
Climate regulation (Regulating) – Oceans and forests store carbon
Pollination (Supporting) – Increases plant growth
142
Describe the key characteristics that determine the likelihood that a species will become
endangered or become extinct
Small population size
Limited range
Specialized needs
Low reproductive rate
High human interaction
Poor dispersal ability
143
What factors make species more vulnerable to extinction?
climate change, pollution, overfishing
144
What is the intermediate disturbance hypothesis?
proposes that species diversity in an ecosystem is maximized when the frequency and intensity of disturbances are at an intermediate leve
145
How do different levels of disturbance affect biodiversity?
Low disturbance:
--Dominant species outcompete others → lower biodiversity 🐘➡️🐜
High disturbance:
--Frequent or intense events (like fires or floods) → few species survive → lower biodiversity 🔥🌊
Moderate disturbance:
--Mix of competition and opportunity for new species → highest biodiversity
