populations and communities

Question 1

What is a population?

Answer 1

A population can be defined as a group of individuals of the same species, living
in a shared space at a specific point in time. Since the individuals in a population share
a common environment, they benefit from the same resources (water, food, sunlight).
Studying populations reveals how various species evolve and therefore gives us an idea
as to whether a species is thriving or declining.

Question 2

what are the 3 main characteristics are used to
describe a population

Answer 2

1. population size
   2.Population distribution
2. population density

Question 3

what is the Population distribution?

Answer 3

This term refers to the way in which individuals are distributed within their habitat.
A clumped distribution refers to a pattern in which animals form groups. Uniform
distribution refers to animals being dispersed equally throughout the population’s
habitat. Random distribution refers to animals that are unpredictably dispersed
across the population’s habitat.

Question 4

what are the factors that effect population size?

Answer 4

Four factors explain these variations: births, deaths, emigration, and immigration (see
p.294).

Question 5

What are ways to measure the population size?

Answer 5

There are many methods used to measure the size of a population. When
possible, we can count all the individuals within the area they occupy. They can do
this by simply counting or by aerial photography. We can also count the individuals
in randomly selected sections of the study area and then estimate the total
we can also mark and recapture

Question 6

What is a quadrat?

Answer 6

To section off a sample area, quadrats (rectangular areas marked off with
ribbons) are often used. Quadrats can only be used for plant populations or for slow
moving animals.

Question 7

what is population density?

Answer 7

animals per km

Question 8

What are important factors to Density?

Answer 8

Density of a population can vary with habitat since water and food are important
factors in determining density. Factors such as climate, parasites or disease and
natural and human disasters can also affect the density of a population.

Question 9

Name the different types of population distribution.

Answer 9

a clumped, Uniformed and random.

Question 10

What is a uniform distribution?

Answer 10

The density of a population can vary with habitat since water and food are important
factors in determining density. Factors such as climate, parasites or disease and
natural and human disasters can also affect the density of a population.

Question 11

What are the two ecological factors?

Answer 11

abiotic and biotic factors.

Question 12

What is a biotic factor?

Answer 12

Biotic factors (living) are related to the actions of the living organisms
in a habitat.

Question 13

What is an abiotic factor?

Answer 13

Abiotic factors (non-living) are physical or chemical aspects of the
environment.

Question 14

Name an example of an abiotic factor.

Answer 14

Temperature, soil, precipitation ,light, terrain, depth of snow and natural disaster

Question 15

What is a limiting factor?

Answer 15

Limiting factors are ecological factors that cause the density of a population to
decrease and explain the presence or absence of individuals in a habitat.

Question 16

What is a Biological cycle?

Answer 16

cycles where species repeatedly experience periods of growth and some decline.

Question 17

What is biodiversity?

Answer 17

Biodiversity refers to the variety of species living in a community.

Question 18

What is competition?

Answer 18

Competition is the interaction between living organisms that are looking for
access to the same resources in their habitat.

Question 19

What is Predation?

Answer 19

Predation is the interaction
between two living organisms where one feeds on the other.

Question 20

What is mutualism

Answer 20

Mutualism refers to the
interaction between two living organisms that benefits both organisms.

Question 21

What is commensalism?

Answer 21

Commensalism is the interaction between two living organisms in which one benefits
while the other is unharmed.

Question 22

What is an ecosystem?

Answer 22

A community of living organisms that interact with one another and with the non living
components.

Question 23

What is a producer?

Answer 23

They are organisms like plants and algae that can transform inorganic matter
(not produced by living organisms) into organic matter (produced by living
organisms). They are called autotrophs (because they feed themselves)

Question 24

What is a consumer

Answer 24

Consumers are incapable of feeding themselves so they are called heterotrophs
They get their energy by eating other living organisms or their products. There are
different types of consumers:
 First order consumers feed on producers (herbivores)
 Second, third, and fourth-order consumers eat consumers of the preceding
order (below them on the food chain) so they are carnivores.

Question 25

A first-order consumer meets a 3rd order consumer, who eats who?

Answer 25

3rd order eats the first order consumer

Question 26

What is a heterotroph?

Answer 26

a consumer

Question 27

What is a decomposer?

Answer 27

Decomposers are connected to all the trophic levels because they feed on
detritus (dead organic matter) and break it down into organic matter. They are also
known as detritivores.

Question 28

what is Primary productivity?

Answer 28

primary productivity of the ecosystem (amount of new biomass made by producers).

Question 29

What is an Ecological footprint?

Answer 29

Ecological Footprint of a population = Land and water occupied +

land and water used to produce goods and
services +
land and water used to dispose of waste

Question 30

What are the 3 things that toxicity depends on?

Answer 30

 Concentration: the more concentrated the contaminant is, the more risk that it
will be toxic.
 The type of organisms it comes in contact with Some contaminants are toxic
to some organisms but not others.
 The length of exposure: The longer a contaminant is in contact with an
organism, the more toxic it is.

Question 31

What is bioaccumulation?

Answer 31

Bioaccumulation is the tendency among certain contaminants to accumulate over time
in tissues of living organisms. The higher up on the food chain the animal is, the higher
the concentration of contaminants it will have accumulated. This is called bioconcentration.

Question 32

What is biodegradation?

Answer 32

Biodegradation: It is the breaking down of organic matter into inorganic matter
by microorganisms. We can introduce microorganisms that can survive highly
toxic environments and feed on contaminants by degrading them. They take the
toxic environment and transform it into a harmless environment through a
process called bioremediation.

Question 33

What is Phytoremediation?

Answer 33

Phytoremediation: It uses plants or algea to eliminate contaminants from a site.
Plants will absorb the contaminants and then will be harvested to be disposed of.

Question 34

What is waste water treatment?

Answer 34

Wastewater treatment: Wastewater is water that has been discharged from
household or industrial waste that may contain contaminants. Septic tanks are
used in homes that are not connected to the sewers (see p. 340). Wastewater
treatment plans are used to decontaminate wastewater (see p.341).

Question 35

Name the 3 biotechnology used to counter environmental problems.

Answer 35

Biodegradation,phytoremediation and waste water treatment

Question 36

(est) Why are animals on the higher tropic levels more susceptible to health problems

Answer 36

Since all the toxins from the lower tropic levels build up the higher the tropic level, this phenomenon is called Bioaccumulation.