College Biology > Lecture 6 - test 2 > Flashcards

Lecture 6 - test 2 Flashcards

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1
Q

What are the levels of ecological organization?

A
  1. Individual
  2. Population
  3. Community
  4. Ecosystem
  5. Biome
  6. Biosphere
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2
Q

What is an ecological community?

A

It consists of all the populations of all the different species that live together in a particular area.

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3
Q

What do ecological communities vary in?

A

the types and numbers of species they contain.

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4
Q

What is community structure?

A

The composition of a community including the number of species in that community and their relative numbers.

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5
Q

What five factors shape community structure?

A
  1. Climate Patterns
  2. Geography
  3. Heterogeneity (patchiness) of an environment
  4. Frequency of disturbances or disruptive events
  5. Interactions between organisms
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6
Q

What are foundation species?

A

Species that play a unique and essential role in creating and defining community.

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7
Q

How do foundations species effect the environment and create community?

A

By modifying the environment.

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8
Q

What are examples of foundation species?

A
  1. Coral - foundation supports entire coral reefs and provides shelter for other animals
  2. Giant kelp - provides shelter for otters
  3. Beaver - effect the shape and size of rivers and streams
  4. Elephants - have a large effect on ecosystems by knocking over trees, eating massive amounts of food, and traveling in groups
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9
Q

What are keystone species?

A

A species that has a disproportionately large effect on community structure relative to its biomass.

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10
Q

What trophic level are keystone species more likely to belong to?

A

Higher trophic levels.

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11
Q

What are examples of keystone species?

A
  1. Wolves in Yellowstone - Over hunting of wolves increased the elk and effected the whole ecosystem
  2. grizzly bears - They distribute nutrients in the soil by dragging fish across soil and digging up bulbs mixing up nutrients
  3. Otters - eat sea urchins
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12
Q

How is community structure measured?

A

By species richness and species diversity.

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13
Q

What is species richness?

A

The number of different species in a particular community.

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14
Q

Where is more species richness found and why?

A

Near the equator because there is more solar energy, warm temperatures, large amounts of rainfall, and little seasonal change.

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15
Q

where is the least species richness found and why?

A

Near the poles because there is less solar energy, colder, dried, and less amenable to life.

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16
Q

What are 4 other hypothesis for why there is more species richness near the equator?

A
  1. More land and ocean
  2. The tropics are less effected by climate change
  3. stable environments allow for narrow niches, which allows multiple species to coexist
  4. Speciation occurs faster and/or extinction is less likely
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17
Q

What is species diversity?

A

A measure of community complexity.

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18
Q

What is species diversity measured in?

A
  1. Species richness
  2. Species evenness
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19
Q

what is species evenness?

A

The relative abundances of each species.

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20
Q

Practice Simson diversity index equation

A

Ds = 1 - (the sum of) (n/N)^2
(n = number of individuals of each species)
(N = total number of individuals)j

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21
Q

What is an ecosystem?

A

A community of living organisms existing in conjunction with nonliving components of their environment, interacting as a system.

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22
Q

What are 2 types of ecosystems?

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A
  1. Natural ecosystems
  2. Artificial ecosystems
23
Q

What are natural ecosystems?

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A

Ecosystems that depend on soil structure, climate, oxygen, carbon dioxide, and water includes forests, grasslands, desserts, and aquatic.

24
Q

What are artificial ecosystems?

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A

Man-modified ecosystems that include agriculture, urban, or industrial land use.

25
What does it mean that ecosystems are dynamic?
The characteristics of ecosystems and their populations vary over time.
26
What are disruptions in ecosystems?
Changes that can happen in either living or nonliving parts of an ecosystem. The changes can affect the populations that live there.
27
What are interactions in an ecosystem?
Interactions that occur in a web so that any change to a part of the ecosystem can lead to changes in many of the ecosystems population.
28
What is an example of ecosystem dynamics in the human population?
The disease outbreak of 1993 when a pulmonary illness effected people of the four corners of the U.S. It was the virus with no name. the virus was spread by the droppings of rats. The rat population had increased because of increased vegetation, which increased the spread of the virus.
29
What percentage of novel or re-emerging infectious diseases that affect humans in the 21st century have had zoonotic origin?
75%
30
What percentage of zoonotic deaseases have originated from wildlife?
Over 70%
31
What are examples of diseases with zoonotic origin from wildlife?
1. HIV/AID 2. Ebola 3. Severe Acute Respiratory Syndrome (SARS)
32
What are cross species pathogen transmission events called?
Spillover events.
33
What is the equilibrium of an ecosystem?
When an ecosystem is in a steady state where all organisms are in balance with their environment and each other.
34
What effect do small changes have on an ecosystem in equilibrium?
It will be balanced by negative feedback, allowing the system to return to its original state.
35
What is a distrubance?
A normal phenomenon in ecosystems that can range in severity from mild to extreme.
36
what are two types of disturbances?
1. Changes that make is less likely that organisms in a population will survive 2. Changes that make it more likely the organisms in a population will survive
37
What are examples of disturbances that make it less likely that organisms will survive?
These cause populations to get smaller such as hurricanes and floods which destroys organisms and their habitat.
38
What are examples of disturbances that make it more likely that organisms will survive?
These cause populations to get bigger such as hurricanes which disperses seeds, modifies habitats, gives needed rain, topples large trees to allow light to lower levels.
39
What is ecological succession?
The sequence of changes that occur in an ecosystem after a disturbance.
40
What is primary succession?
The initial colonization of a area by living organisms. It creates life in areas where there was no life before.
41
What is an example of a primary succession?
Volcanic activity creates a new lanscape.
42
What are the steps to primary succession?
1. It begins with no soil 2. Starts with the arrival of pioneer species such as lichen (which don't need soil to survive) 3. Lichens decompose into organic matter forming soil over time 4. Simple plants like ferns and moss grow 5. Simple plants die, adding more organic matter 6. Soil layer thickens, and grasses and other plants can grow 7. These plants die, adding more nutrients to the soil and shrubs and trees grow 8.Insects and small animals move in
43
What is secondary succession?
The recolonization of an area after disturbance.
44
Is most succession primary or secondary?
Secondary.
45
What is re-stabilization?
A process that follows a disturbance in an area where life has formed.
46
What happens during secondary succession?
The soil remains intact, but one community replaces another which has been partially or totally destroyed.
47
What can secondary succession be cause by?
Natural disasters, floods, earthquakes, fire.
48
What is the final stage of secondary succession?
Climax community, a mature, stable community that remains the same throughout time if it is not disturbed.
49
What is ecosystem stability?
The ability of an ecosystem to defy change or rebound from change. The more stable, the faster it heals and bounces back.
50
What is ecosystem resistance?
The ability of an ecosystem to remain at equilibrium despite disturbances.
51
What is ecosystem resilience?
The speed at which an ecosystem recovers to equilibrium after being disturbed.
52
what are human activities that negatively affect ecological resilience?
1. Reduction of biodiversity 2. Exploitation of natural resources 3. Pollution 4. Land use 5. Anthropogenic climate change
53
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