T14 - Biosphere and ecology

Question 1

What is ecology?

Answer 1

The study of how organisms interact with each other and their environment

Interactions depend on biotic factors (other organisms) and abiotic factors (physical and chemical properties of the environment)

Question 2

What is organismal ecology?

Answer 2

How organism structure, physiology and behaviours repsond to the environental challenges

Question 3

What is population ecology?

Answer 3

How biotic and abiotic factors affect population size and how it changes through time

• Population dynamics and growth

Population = group of indivs of the same species living in an area

Question 4

What is community ecology?

Answer 4

How interactions between species (predation, competition, mutualism) affect community structure and organization

Community = group of populations of different species in an area (these can be microorganisms, plants, animals..)

Question 5

What is ecosystem ecology?

Answer 5

How energy and chemicals cycle between organisms and the environment

Ecosystem = community of organisms in an area and the physical factors with which those organisms interact

• Takes into factors such as how carbon cycles, humidity levels, resource availability

Question 6

What is landscape ecology?

Answer 6

What factors control exchanges of energy, material and organisms across multiple ecosystems and how

Lanscape = mosaic of connected ecosystems

• Taking note of effects of things like erosions, volcanic eruptions

Question 7

What is global ecology? What is another term for this ?

Answer 7

How the regional exchange of energy and materials influenecs the functioning and distribution of organisms across the biosphere

Global ecosystem (biosphere) = sum of all planets ecosystems and landscapes

• Can compare differences in populations on tropic regions vs oceanic regions globally

Question 8

What is climate? What 4 factors determines this?

Answer 8

Long term weather conditions in a given area

Determined by; temperature, light, wind, precipitation

Question 9

What is a biome?

Answer 9

A major ecosystem type classified according to the predominant vegetation and the physical environment and characterized by adaptations of organisms to that environment

Question 10

Where do species occur and why?

Answer 10

Distribution of a species depends on its evolutionary history, biotic factors and abiotic factors

• pace of evolution and how species evolved (specialized)

Question 11

Where is the highest and lowest diversity found?

Answer 11

Highest diversity in tropics and near shore areas

Lowest diversity near the poles

Question 12

What is species richness?

Answer 12

Number of species in a biological community

• increase = more speciation (more species have evolved or less extinction has occurs

Question 13

What are 3 hypotheses that can help explain the gradient in species richness?

Answer 13

1. Tropical latitudes receive more solar energy than temperate zones

• more photosynthesis can occur with more sunlight = much longer growing season
• higher productivity
• increase in biodiversity with more resources to accomodate and maintain a wider variety of different species

2. Fewer seasonal changes in tropical regions (more stable climate)

• Increase competition leads to a smaller niche (forces them to specialize for one resource)
• leads to an increase in specialization and resource partitioning (fewer species that can exploit the same resource as another = less competition)
• increase in biodiversity
• resources remain stable, there is no need to acclimate to multiple environments/habitats/seasonal changes

3. During the ice age, temperate communites were vulnerable to glaciations

• Tropical communities are typically older and have stayed undisturbed for longer
• reduced extinction rates in the tropics
• increase in biodiversity, increase in level in speciation, may have this in temperature regions but they have a higher extinction rate
• glaciation happened near the pole regions, not affecting these tropical regions

Question 14

What is the net diversification rate?

Answer 14

Speciation - extinction

Question 15

What is a generalist vs a specialist? What is an example of both?

Answer 15

Generalist = species that thrives in a wide varitey of environmental conditions (different resources)

Ex. raccoons that can eat berries, insects, small animals

Specialist = species that thrives only in a narrow range of environmental conditions (very specific resources)

Ex. Koalas feed almost exlcusively on eucalyptus leaves

Question 16

What is dispersal?

Answer 16

Movement of indivs away from the area of origin or from centers of high population density

Dispersal might limit its distribution because some may not be accessible or there may not be enough time for a species to adapt to new seasons

There may also be the presence of an invasive species limiting disperal distribution

Question 17

How can species living along an environmental gradient respond to climate change?

Answer 17

a) Natural range limited to physiological factors (original population might be more climatically suited to one area)

b) Natural range is shifted north = species will colonize new areas

c) shrinkage of natural range because of limited number of habitats avail in the north and south ern limit moving north

d) dispersal barriers prevent colonization of potentially suitable habitats (environmental barriers - mountains - that may block new possible habitats)

e) limited dispersal abilities prevent keeping up with rapidly changing conditions

f) adaptation to new conditions and expansion of the natural range (evolutionary change)

Question 18

List some examples of species interactions that may influence the composition and dynamics of communities

Answer 18

Mutualism (both benefit)

Commensalism (one benefits, the other is not affected)

Parasitism (one benefits, the other is harmed)

Neutralism (neither are benefitted or harmed)

Amensalism (one is harmed, the other is not affected)

Competition (both species are harmed)

Question 19

What is the difference between the realized niche and the fundamental niche?

Answer 19

The realized niche is always smaller than the fundamental niche because of competition

• when 2 indivs of different species compete for a resource, limiting their growth and survival

Question 20

What is competitive exclusion?

Answer 20

When populations of 2 similar species compete for the same limited resource (same prey/occupying the same habitat)

One population will use the resources more efficiently (reprod advantage) leading to the elimination of the other population

Essentially, one species ‘wins’ against the other

Question 21

What is resource partitioning? What does it accomplish?

Answer 21

The differentiation of ecological niches

Can decrease competition and allow 2 species to coexist

• Different adaptations allow them to exploit different resources
  Ex. 7 species of anolis lizards that coexist in the same habitat but occupy different niches (different legs; shorter/longer for catching different prey)

Question 22

What is bottom up control vs top up control?

Answer 22

The controlling of populations of intermediate trophic levels;

Bottom = amount of food available in lower trophic levels

Top = presence of predators