Populations and communities

Question 1

What is population defined as?

Answer 1

A group of individual organisms of the same species living in a given area.

Question 2

What is reproductive isolation?

Answer 2

When two populations live in different areas, making them unlikely to interbreed with each other.

Question 3

What happens when the same species are geographically isolated?

Answer 3

They’ll develop differences and eventually evolve into different species

Question 4

Why is population size estimated rather than counted?

Answer 4

Because it’s impossible to accuratley count every individual member of a population

Question 5

What are two common sampling methods for immobile organisms?

Answer 5

Quadrat sampling and line/belt transects.

Question 6

What is carrying capacity?

Answer 6

The maximum size of a population that an environment can support.

Question 7

What can limit the carrying capacity?

Answer 7

Water, food, space and oxygen.

Question 8

What are examples of density independent factors?

Answer 8

Droughts, wildfires, hurricanes, etc

Question 9

What are examples of density dependent factors?

Answer 9

Competition, infection, and predation

Question 10

What are examples of positive and negative feedback in populations?

Answer 10

Positive feedback leads to breeding increases, density dependent factors lead to negative feedback to prevent exponential growth.

Question 11

What are the 3 pieces a sigmoid graph is split into?

Answer 11

The exponential phase, where the population increases rapidly, the transitional phase, where the population growth slows as limiting factors have increasing effects, and the plateau phase, where a population remains close to carrying capacity.

Question 12

What are competitive relationships?

Answer 12

Competitive relationships are when members of the same species have to compete for the same resource, unless the resource is abundant. An example is plants competing for light

Question 13

What are cooperative relationships?

Answer 13

Cooperative relationships are when both species have strong benefits because all individuals benefit. AN example is animals huddling for warmth.

Question 14

What is a community?

Answer 14

A group of populations living together in an area and interacting with each other

Question 15

What are interspecific relationships?

Answer 15

Interspecific relationships are relationships that occur between DIFFERENT species within an ecosystem. Herbivory is an example of this.

Question 16

What is interspecific competition?

Answer 16

Interspecific competition is when different species compete for limited resources within an ecosystem. An example of this is the eastern grey squirrel and american red squirrels competing in north america.

Question 17

What is mutualism?

Answer 17

Mutualism is when both parties obtain benefits from the relationship. For example, bees and flowering plants.

Question 18

What is parasitism?

Answer 18

Parasitism is when one organism benefits at the expense of it’s host. Tapeworms are an example of this.

Question 19

What is pathogenicity?

Answer 19

Pathogenicity is when a pathogen capable of causing a disease invades and multiplies within the host’s tissues, disrupting normal physiological functions.

Question 20

How do fabaceae plants and rhizobum bacteria help each other?

Answer 20

The plant provides root noodles for bacteria to live in, maintains low oxygen conditions, and supplies sugars to it. The bacteria absorbs nitrogen and produces ammonium, supplying it to the plant. Prevents nitrogen deficiency, giving the plant a competitive advantage.

Question 21

How do orchids and fungus help each other?

Answer 21

Orchid provides carbon compounds made from photosynthesis, the fungus absorbs nitrogen and phosphorus from the soil and gives it to the orchid, as well as carbon and water.

Question 22

How do zooxanthellae and hard coral help each other?

Answer 22

Zooxanthellae live within the tissues of hard corals, providing them with essential nutrients Coral provides a safe, protected environment, light and CO2. Zooxanthellae provides carbon and oxygen.

Question 23

What are endemic species?

Answer 23

Endemic species are species that occur naturally in the area.

Question 24

What are invasive species, and what’s an example of one?

Answer 24

Invasive species are introduced by humans, deliberately or accidentally. An example is the emerald ash borers. They’re destructive beetles native to Asia. They were first detected in Minnesota in 2009, and have become an issue.