2.1 Species and Populations

Question 1

Define ecology

Answer 1

Ecology is the study of the interactions between organisms and the environment in which they live in

Question 2

Define ecosystem

Answer 2

A community of interdependent organisms and the physical environment they interact with and the interactions between biotic and abiotic components

Question 3

Define species

Answer 3

Speciesis a group of organisms with common characteristics that can interbreed to produce fertile offspring.

Question 4

Define population

Answer 4

Apopulationis agroupof individuals of the same species living in the same area at the same time.

Question 5

What is population size determined by?

Answer 5

• Births and immigration – which increase population size.
• Deaths and emigration – these decrease population size.

Question 6

Define: biotic components

Answer 6

The biotic element of the ecosystem is anything that is living and any interactions between the living components.

Question 7

What do the biotic components include?

Answer 7

Producers: Plants that turn energy into matter

Consumers: Animals that eat other animals

Decomposers: Organisms that breakdown waste into component parts for reuse

Question 8

Interactions between living components:

Answer 8

• predation
• herbivory
• paratism
• mutualism
• disease and competition

Question 9

Define: abiotic components

Answer 9

The non-living components of an ecosystem

Question 10

What are some abiotic factors?

Answer 10

Sunlight, water, PH, salinity, precipitation

Question 11

Define habitat

Answer 11

Ahabitatis the environment in which a species usually lives and it has the physical and biological resources that an organisms needs

Question 12

What is a niche?

Answer 12

Thenicheis the role an organism plays and the position it holds in the environment. It includes all the interactions the organism has with the abiotic and biotic environment.

Question 13

Realized niche

Answer 13

Realized Niche:

The ACTUAL ecological role and habitat where a species exists in nature, TAKING INTO account interactions with other species and limitation

Question 14

Fundamental niche

Answer 14

The COMPLETE range of environmental conditions and resources where a species could potentially exist and thrive, WITHOUT CONSIDERING interactions or limitations.

Question 15

What is a limiting factor? (Hint: remember there is an extra part that is IMPORTANT)

Answer 15

Limiting factorsare the resources in the environment that limit the growth, abundance and distribution of organisms/populationsin an ecosystem.

IMPORTANT: The size of a population and the rate at which it increases is determined by the limiting factors

Question 16

What are density dependent factors? (Give ex.)

Answer 16

These affect the population only when it reaches a CERTAIN density

Ex. Competition, disease, parasitism and predation

Question 17

What are density independent factors? (Give ex.)

Answer 17

These will control populations NO MATTER WHAT the density of it is.

Ex. Sunlight, temperature, water, natural disasters

Question 18

Define carrying capacity

Answer 18

TheMAXIMUM NUMBER of individuals of a species that the environment can sustainably support in a given area.

Question 19

What does the J-curve show?

Answer 19

Exponential population growth under ideal conditions (plenty of resources, ideal conditions)

Until the enviroment/habitat of the population reaches its carrying capacity

Question 20

What type of strategists are populations that follow the J-curve and what are their characteristics?

Answer 20

R-strategists

Characteristics:

• High Reproductive Rate
• Early Reproduction (reach maturity at young age)
• Short Lifespan
• Small Body Size
• High Dispersal
• Generalists (able to adapt to many enviromental conditions

Question 21

What does the S-curve show?

Answer 21

A population growth when resources are limited

Exponential growth is only possible for a short period of time because as the population grows resources are depleted and the growth rate slows and will eventually plateau off

Question 22

What type of strategist follows the S-curve and what are their characteristics?

Answer 22

K-strategists

Characteristics:
- low reproductive rate
- delayed reproduction (reach maturity later than k strategists)
- long lifespan
- larger body size
- parental care
- all results in fewer offsprings

Question 23

State the types of species interactions (hint: 5)

Answer 23

• Predation
• Herbivory
• Parasitism
• Mutualism
• Competition

Question 24

Define Predation

Answer 24

Predationis where one organism (the predator) hunts and kills another (the prey) in order to provide it with the energy for survival and reproduction.

Question 25

How is predation a negative feedback loop? (Hint: Explain cycle)

Answer 25

➕ prey = ➕ predators = ➕ predators → ➖ prey = ➖ prey = ➖ predators = ➕ prey…

Question 26

Define Herbivory + Give one example of defense mechanisms developed by plants to slow down herbivory

Answer 26

Definition
Herbivoryis the consumption of plant material by an animal

Ex of defense mechanism
Horns or Prickles

Question 27

Define parasitism

Answer 27

Parasitismis when anorganism (the parasite) takes nutrients from another organism (the host).

Question 28

Differentiate: Ectoparsites vs endoparasites

Answer 28

• Ectoparasites: outside the host (think: exoesqueleto: ECTO). eg. fleas
• Endoparasites: inside the host eg. plasmodium (parastie that causes malaria

Question 29

Define mutualism and give an example

Answer 29

Mutualismis where two organisms of different species exist in a mutually beneficial relationship. It is a type of SYMBIOTIC relationship

Example
Bacteria in the intestines of cows, bacteria eat and they facilitate the cows digestion (winwin)

Question 30

Define competition

Answer 30

Competition is where organisms compete for a resource that is in limited supply

Question 31

What are the two types of competiton? Define and give examples

Answer 31

1. INTRAspecific competitionoccurs when members of the same species compete for a limited resource
2. INTERspecific competitionis where members of different species compete for a resource that they both need.