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Biology TS > Ecology Part 3 > Flashcards

Ecology Part 3 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Population

A

A group of organisms of the same species inhabiting the same area at the
same time

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2
Q

Community

A

Interacting populations occupying the same area

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3
Q

Ecological species

A

A set of organisms occupying the same niche

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4
Q

Biological species

A

Closely related organisms capable of interbreeding and producing fertile
(viable) offspring

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5
Q

How is Population size (number of individuals in a population) affected?

A

Birth (increases population size)

Death (decreases population size)

Migration (increases or decreases population size)

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6
Q

What is recruitment?

A

Number of birthed offspring attaining maturity (added adults)

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7
Q

What is Biotic Potential?

A

Maximum rate at which population can increase in ideal conditions

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8
Q

What is Environmental Resistance?

A

Set by a combination of biotic and abiotic factors

Establishes the Carrying Capacity (max population size supported)

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9
Q

What is biotic potential detailed?

A

Rate at which population increases in ideal conditions

No competition
Unlimited resources
Therefore, unrestricted exponential growth

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10
Q

Which are the influential factors of biotic potential?

A

Age at sexual maturity

Average frequency of reproduction

Average number of offspring produced per batch

Average reproductive life span

Average death rate under ideal conditions

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11
Q

What happens in Exponential Growth? (Biotic Potential)

A

Growth without limits

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12
Q

What happens in Logistic Growth? (Environmental resistance)

A

Competition limits growth.

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13
Q

What is environmental resistance and some examples?

A

Environmental limits set by biotic and abiotic factors

Food availability
Habitat space
Competition (intraspecific and interspecific)
Disease
Parasitism

Increases death rate and lowers birth rate
Balances population size around an ideal density
Population quickly reaches set limit and then fluctuates around it

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14
Q

What are growth curves?

A

Graphical representation of population growth

Population growth pattern is often repetitive on a small scale

Many mini booms and mini busts (depending on environmental resistance)
Graphs more complex than simple curve

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15
Q

Factors of an S Shaped (Sigmoid) Growth Curve?

A

Density dependent growth

As numbers increase, growth slows down

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16
Q

Factors of a J Shaped Growth Curve?

A

Density independent growth

Growth continues to speed up exponentially until the carrying capacity is exceeded

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17
Q

J-Shaped Growth Curve (detailed)

A

Lag phase is followed by a log phase until the population suddenly crashes

Also called the “boom and bust” cycle

Growth is Density Independent
Population grows quickly and then crashes
this cycle is repeated incessantly

Influential factors include:
Seasonality, breeding phases, human intervention (e.g. pesticides), seasonal climatic extremes (e.g.floods, fires or droughts)

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18
Q

what is the exponential growth equation?

A

dN/dt = rN

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19
Q

S-Shaped growth curve (detailed)

A

Growth is Density Dependent

Curve is Logistic

Lag phase (slow growth due to adjustment and few numbers)
Log phase (max birth rate growth speeds up as numbers increase)
Deceleration phase (environmental resistance increases with increasing density)
Stationery phase (recruitment and death even out)

Saturation Value or Carrying Capacity is reached

Death phase (death rate exceeds birth rate due to increasing environmental
resistance)

Fast growth when density is low; slow growth when density is high
Influential factors include competition, (including predation) parasitism (including disease), overcrowding and stress

20
Q

What is the logistic growth equation?

A

dN/dt = rN (K-N/K)

21
Q

Which are the population strategies?

A

r-strategist

K-strategist

22
Q

What are opportunist species?

A

Also called r selected species or r strategists

high growth rate

produce many offspring with low probability of surviving

Exploit less crowded ecological niches

Predominate in disturbed or unstable environments

23
Q

What are Equilibrium species?

A

Also called K selected species or K strategists

Low growth rate

Produce few offspring with increased probability of survival

Better competitors (can survive in more crowded niches)

Predominate in stable and predictable environments

24
Q

How many Survivorship Curves types are there?

A

3 types of curves

25
Q

Explain type 1 curve

A

High probability of survival throughout their life with a sudden drop at a specific
age

Parental care, low birth rates, and extended social networks (herds, packs, or colonies)
improve survival rates

E.g. Elk, White tailed Deer, Grey Wolves, and Humans

26
Q

Explain type 2 curve

A

Steadily declining probability of survival throughout their life

Parental care, moderate to low birth rates, and extended social networks but small to
moderate in size and are a key prey source of prey

E.g. Sandhill Cranes and Coyotes

27
Q

Explain type 3 curve

A

Very rapid decline in probability of survival early in life and then a good probability
of survival late in life

Large body size or physical/behaviour defence mechanisms

E.g. Northern Pike, Water Hyacinth, and Autumn Olive

28
Q

Population size information card

A

Population size fluctuates even when stable

Abiotic and biotic factors continue to influence population size

Sometimes these factors are cyclical

Some factors affect birth rate (population growth)

Other factors affect death rate (population decline)

29
Q

Intraspecific factor- Density Dependent Factors (mostly biotic)

A

Effect increases with increasing population density

E.g. food shortage, territorial behaviour, overcrowding and dispersal

30
Q

Intraspesific factor- Density Independent Factors (mostly abiotic)

A

Effect is not related to population size

E.g. edaphic factors, climatic factors, natural disasters, and pollution

31
Q

Food Shortage information card

A

Individuals suffer the effects of malnutrition

Increased mortality

Especially young

Reduced resistance to disease and parasites

Reduced fecundity (or altogether absent)

Inherent defensive behaviour may be lost

In severe starvation cases, animals may seek food beyond adequate cover against discovery by predators

This leads to increased mortality through
predation

Water shortage is just as debilitating

32
Q

Territorial Behaviour (Territoriality) information card

A

Low population density

One or both individuals in a pair establish a territory

The extent of the territory is marked chemically, visually, or through calls

Challengers are seen off after a ritual fight

There is no overlap between individual territories

High population density

Territorial size diminishes

Only the toughest maintain adequate territories

These individuals survive and/or reproduce to the detriment of others of the same species (Intraspecific Competition)

This is also called Regulation through Spatial Interaction

33
Q

Overcrowding information card

A

Low population density

Population behaves normally

High population density

Effects of Social Stress are observed in small mammals

Diminished reproductive organs

Reduced reproductive rate

Slower growth

Reduced disease resistance

Reduced parental care

Young abandon nest early and die more often as a consequence

Cannibalism of the young (Intraspecific Competition)

These symptoms appear even in cases of high food availability

34
Q

what are examples of interspecific interactive relationships?

A

Predator prey relationships

Parasite host relationships

Interspecific competition for resources

35
Q

Predator-Prey interactions

A

Predator species feed on their designated prey species

Predators control prey populations

This is a density dependent interaction

36
Q

Experiments in the lab show that predator and prey populations interactions
follow a distinct pattern

A
  1. A crash in a prey population leads to a similar predator population crash
  2. The reduced number of predators boosts the prey population which recovers
  3. The now abundant prey population boots the predator population
  4. The increase in predators cause the prey population to crash (cycle complete)

The two populations are slightly out of sync

it takes some time for the effect to be felt

Lab conditions preclude predators selecting alternative prey so field results could be
different (also, other density dependant factors may apply, e.g. disease and overgrazing)

37
Q

Parasite-Host Interactions information card

A

Parasites only attack designated host species

Parasites weaken hosts and may make them more vulnerable to disease or predators

This is another density dependant interaction

Overcrowding means parasites spread faster and wider

Under normal circumstances, parasites have limited mobility

Many parasitic strategies have evolved

E.g. conventional parasite, parasitoid and parasitic castrator

38
Q

Interspecific Competition

A

Predators and parasites keep populations within the k limit

They cull the least fit individuals

Only most fit individuals survive to reproduce

Target species involved in “arms race” with predators and
parasites

This is called Coevolution

It is a major evolutionary drive

39
Q

Keystone Species

A

•
Disproportionately large effect on the community

Maintain biodiversity by controlling dominant species

Provide critical resources for a wide variety of species

Fundamental community structure changes if this species is removed

Not all communities include keystone species

If present, they are critical to the environment and community

40
Q

Examples of keystone species

A

E.g. Pisaster ochraceus (starfish)

Major predator of the mussel Mytilus

When the starfish is removed, mussels take over the community and displace the other 25 or so species of invertebrates and algae in the environment

Other examples

Sea otters and sea urchins; grey wolves in the Greater Yellowstone ecosystem

41
Q

Ecological Niche

A

How an organism utilises its environment

E.g. spatial utilisation, food consumption, temperature range, mating
requirements, moisture conditions, etc

42
Q

Fundamental (Potential) niche

A

Full range of conditions in which organism can survive

43
Q

Realised (Actual) niche

A

Actual range of conditions occupied by the organism

44
Q

Chthalamus vs Semibalanus information card

A

Study carried out along the coast of Scotland

Competitive interactions between two types of barnacles

Chthalamus stellatus can withstand a wide range of
submersion/exposure

However it is the weaker competitor

Semibalanus balanoides cannot withstand long exposure

It is the stronger competitor

If present alone, C . stellatus occupies the shallow and deep
zones

The presence of S . balanoides in deeper zones prevents C . stellatus from occupying its full niche as it is outcompeted

45
Q

Niche Strategies- Generalist Species

A

Characteristics

Wide fundamental niche

Can exist in many different environments

Can use a wide range of resources

Good opportunistic species

Generally successful at colonising new
environments

Good at surviving environmental changes

Can tolerate a wide variety of conditions

Generally evolve at a faster pace

Tend to be put under greater environmental
pressures

Examples

Omnivores, humans, weeds

46
Q

Niche Strategies-Specialist Species

A

Characteristics

Narrow fundamental niche

Can exist only in specific environments

Limited to a narrow range of resources

Often equilibrium species

Need stable environment

Generally outcompete the generalists

Not likely to survive environmental changes

Narrow tolerance limits

More vulnerable to extinction

Not likely to be flexible enough to survive change

Examples

Pandas, koalas, giraffes, xerophytes

Biology TS (1 decks)

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