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Ecosystems And Populations Flashcards

(73 cards)

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1
Q

What is an ecosystem?

A

All the living organisms and their interactions in a defined area along with all the abiotic factors.

Includes interactions among organisms and physical elements like soil, water, and climate.

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2
Q

What are edaphic factors?

A

Soil types affecting ecosystems.

Includes characteristics like texture, drainage, and nutrient content.

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3
Q

Describe sand as an edaphic factor.

A

Coarse, well-separated particles allowing for free drainage; does not retain water well and is easily eroded.

Ideal for certain types of vegetation but can lead to nutrient loss.

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4
Q

Describe clay as an edaphic factor.

A

Fine particles that easily waterlog and clump when wet.

Holds water and nutrients but can be difficult for roots to penetrate.

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5
Q

Describe loam as an edaphic factor.

A

Sand and clay in equal proportions, retains water, and has good drainage.

Considered ideal for most plant growth.

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6
Q

Why are ecosystems considered dynamic?

A

They can change in three ways: cyclical, directional, and erratic.

Changes can include predator-prey relationships, coastal erosion, or unforeseen events.

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7
Q

What are producers in an ecosystem?

A

Organisms that supply chemical energy to all other organisms, e.g., plants and algae.

They form the base of the food chain.

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8
Q

What are primary consumers?

A

Herbivores that feed on plants directly.

Examples include rabbits and deer.

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9
Q

What are secondary consumers?

A

Organisms that eat primary consumers.

Examples include small carnivores like foxes.

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10
Q

What are tertiary consumers?

A

Organisms that eat secondary consumers.

Examples include larger predators like eagles.

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11
Q

What role do decomposers play in an ecosystem?

A

They feed on waste material from any trophic level.

Include bacteria and fungi that break down organic matter.

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12
Q

What do arrows in energy diagrams represent?

A

Energy transfer between trophic levels.

Illustrates the flow of energy through an ecosystem.

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13
Q

How is energy lost in an ecosystem?

A

Through respiration, indigestible parts of organisms, dead organisms, and reproductive activities.

Energy loss limits the number of trophic levels.

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14
Q

What is biomass?

A

The living material present in an organism.

Can be calculated by the number of organisms at each trophic level present in an area.

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15
Q

How is biomass typically calculated?

A

By averaging the number of organisms at each trophic level in a sample area.

Results may not always be representative of the whole population.

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16
Q

Fill in the blank: Energy is lost during respiration in the form of _______.

A

heat

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17
Q

What percentage of energy consumed by animals is used to make biomass?

A

Only a small percentage is used to make biomass

This biomass is what is available to the next trophic level.

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18
Q

What does ecological efficiency refer to?

A

The energy transfer between trophic levels

It quantifies how much energy is passed from one trophic level to the next.

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19
Q

Why is the conversion of sunlight into usable energy biomass for photosynthesis inefficient?

A
  • 90% of sunlight is reflected
  • Limiting factors of photosynthesis can impact it
  • Energy is lost during photosynthesis

These factors contribute to the overall inefficiency of energy conversion.

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20
Q

What is gross productivity?

A

Total solar energy converted to biomass

It measures the total amount of energy captured by photosynthesis.

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21
Q

How can biomass changes be measured?

A

By swapping energy for biomass

This method allows for tracking productivity changes.

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22
Q

What is the formula for efficiency in energy transfer?

A

Efficiency = (Energy available after transfer / Energy available before transfer) x 100

This formula calculates the efficiency of energy transfer between trophic levels.

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23
Q

What factors can increase the productivity of plants?

A
  • Rate of photosynthesis
  • Light intensity at optimum 24 hours a day
  • Maintain optimum temperature for growth (around 25°C)
  • Use greenhouse conditions
  • Spray with pesticides
  • Increase CO2 levels with burners in greenhouse

These factors enhance plant growth and productivity.

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24
Q

How can productivity be increased in animals?

A
  • Stop movement to minimize energy waste
  • Cull/harvest once animals reach adulthood
  • Convert feed into biomass during growth for profit

These strategies are aimed at maximizing energy efficiency in animal production.

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25
What occurs during anaerobic respiration?
Reduction reaction
26
What is nitrogen fixation?
Nitrogen gas is converted into ammonia by nitrogen-fixing bacteria
27
Where does nitrogen fixation occur?
In root nodules of plants
28
Which bacteria converts nitrogen gas into ammonia in root nodules?
Rhizobium
29
What form does nitrogen gas take when absorbed by plants?
Nitrate
30
Which bacteria converts nitrogen gas into ammonia in free-living conditions?
Azotobacter
31
What does ammonia dissolve in to form ammonium ions?
Water
32
What is nitrification?
The process of converting ammonia into nitrite and then nitrate
33
What is the first step in nitrification?
Ammonia is converted to nitrite using Nitrosomonas
34
What is the second step in nitrification?
Nitrite is converted to nitrate using Nitrobacter
35
What process involves decomposers breaking down nitrogen-containing compounds into ammonia?
Ammonification
36
What do decomposers feed on during ammonification?
Corpses and excretions
37
What is denitrification?
The conversion of nitrate into nitrogen gas by bacteria
38
Which bacteria is involved in denitrification?
Pseudomonas denitrificans
39
What natural phenomenon directly fixes nitrogen gas into ammonia?
Lightning
40
What are detritivores?
Organisms that speed up the decomposition process
41
Give an example of detritivores.
Woodlice and earthworms
42
Fill in the blank: Nitrification requires _______.
Oxygen
43
True or False: Ammonification occurs without the involvement of decomposers.
False
44
What is the process by which plants absorb CO2 during the day?
Photosynthesis ## Footnote Photosynthesis occurs during the day, leading to decreased CO2 levels as plants absorb carbon dioxide.
45
What happens to CO2 levels at night in plants?
Plants respire and release CO2 ## Footnote During the night, plants do not photosynthesize, leading to an increase in CO2 levels as they release carbon dioxide.
46
What effect does winter have on CO2 levels due to photosynthesis?
CO2 levels increase ## Footnote In winter, there is less sunlight, which reduces photosynthesis and results in higher CO2 levels.
47
How do fossil fuels affect CO2 levels?
Burning fossil fuels increases CO2 levels ## Footnote The combustion of fossil fuels releases stored carbon into the atmosphere, raising CO2 concentrations.
48
What are the first organisms to colonize bare rock in primary succession?
Moss and lichens ## Footnote These pioneer species can survive in extreme conditions and initiate the soil formation process.
49
What do pioneer species do to the rock during primary succession?
Break down the rock to form soil ## Footnote As pioneer species die, they add nutrients to the developing soil.
50
What type of community follows the pioneer community in primary succession?
Intermediate community ## Footnote This community is characterized by increased soil quality and competition among plant species.
51
What characterizes a climax community?
Dominated by one or two species ## Footnote A climax community is more stable and less biodiverse than the intermediate community.
52
True or False: The climax community is more biodiverse than the intermediate community.
False ## Footnote Climax communities are dominated by fewer species, making them less biodiverse.
53
What role do decomposers play in the carbon cycle?
Break down dead organisms during decomposition ## Footnote Decomposers recycle nutrients back into the ecosystem, contributing to soil health.
54
Fill in the blank: The carbon cycle includes processes such as photosynthesis, respiration, and _______.
decomposition ## Footnote Decomposition is a crucial part of the carbon cycle as it recycles carbon back into the environment.
55
What is the role of nitrogen-fixing organisms in ecosystems?
They can fix nitrogen directly from the air ## Footnote Nitrogen-fixing organisms convert atmospheric nitrogen into forms usable by plants.
56
What factors control populations according to density?
Density-dependent factors ## Footnote These factors include competition for resources among organisms.
57
What is lag time in population growth?
Growth is slow and reproduction is local as organisms adapt to the environment ## Footnote Organisms need to find shelter, food, and mates while growing.
58
What occurs during the exponential phase of population growth?
Exponential growth of the population due to abundant nutrients, food, and shelter ## Footnote The reproduction rate exceeds the death rate.
59
What is the stationary phase in population dynamics?
Carrying capacity is met; population size fluctuates around this capacity ## Footnote Reproduction rate equals death rate.
60
What is intraspecific competition?
Competition between individuals of the same species ## Footnote
61
What is interspecific competition?
Competition between different species occupying the same niche ## Footnote Example: Grey squirrels outcompeting native red squirrels in the UK.
62
How does predator-prey interaction affect population sizes?
Increase in predator population leads to a decrease in prey population, which later affects predator survival ## Footnote This creates a cyclical effect on both populations.
63
What is the evolutionary arms race?
Natural selection between predators and prey leading to adaptations in both ## Footnote Prey evolve faster speeds and better surveillance; predators adapt with stealth and coordination.
64
Fill in the blank: The _______ phase of population growth is characterized by lag time and slow growth.
Lag time
65
True or False: The reproduction rate exceeds the death rate during the stationary phase.
False ## Footnote In the stationary phase, reproduction rate equals death rate.
66
What are the characteristics of R-strategists?
Short life span, high reproduction rate, and small size ## Footnote These organisms typically grow quickly and reproduce rapidly.
67
What are the characteristics of K-strategists?
Long life span, low reproduction rate, and large size ## Footnote These organisms invest more in nurturing fewer offspring.
68
describe stabalising selection
occurs when the most common phenotype can improve the adaptation of a population extreme phenotypes are selected against The bell curve will narrow
69
Describe directional selection
Occurs when extreme phenotype is favoured Curve will shift and move in one direction
70
Describe disruptive selection
Two or more extremes are favoured rather than the most common phenotype Results in two peaks
71
Characteristics of pioneer community
Small Short lifecycle Can survive in extreme environments Self pollinating Very few animal species (only insects)
72
Characteristics of climax communities
More species Larger species Can’t survive extreme conditions Needs more nutrients in soil Slow in growing Less biodiversity
73
What would a cell in interphase look like under a microscope
Single area of dark stain Individual chromosomes wont be visible Wont be stained as dark

Biology (7 decks)

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