19.1 - Populations In Ecosystems

Question 1

Define ecology

Answer 1

the study of the inter-relationships between organisms and their environment

Question 2

What are abiotic factors

Answer 2

• non-living factors
• such as: temperature and rainfall

Question 3

What are biotic factors

Answer 3

Living factors, such as competition and predation.

Question 4

What are ecosystems

Answer 4

Ecosystems are dynamic systems made up of a community and all the non-living factors of its environment.

Question 5

What are the 2 main processes within an ecosystem

Answer 5

• the flow of energy through the system
• the cycling of elements within the system.

Question 6

Within each ecosystem, there are a number of species. Each species is made up of a group of individuals that make up a _________

Answer 6

Population

Question 7

What is a population

Answer 7

A population is a group of individuals of one species that occupy the same habitat at the same time and are potentially able to interbreed.

Question 8

An ecosystem supports a certain size of population of a species called the _______ ________

Answer 8

Carrying capacity

Question 9

The size of a population can vary as a result of…..

Answer 9

• the effect of abiotic factors
• interactions between organisms, for example, intraspecific and interspecific competition and predation.

Question 10

Populations of different species form a ________

Answer 10

Community

Question 11

Define community

Answer 11

All the populations of different species living and interacting in a particular place at the same time

Question 12

What is a habitat

Answer 12

A habitat is the place where an organism normally lives and is characterised by physical conditions and the other types of organisms present.

Question 13

How many types of habitat do you get in an ecosystem

Answer 13

Multiple

Question 14

What are microhabitats

Answer 14

• Within each habitat there are smaller units, each with their own microclimate. These are called microhabitats
• e.g. mud at the bottom of a stream is a micro habitat for bloodworms

Question 15

What is a niche

Answer 15

• A niche describes how an organism fits into the environment.
• it refers to where an organism lives and what it does there. It includes all the biotic and abiotic conditions to which an organism is adapted in order to survive, reproduce and maintain a viable population.
• Some species may appear very similar, but their nesting habits or other aspects of their behaviour will be different, or they may show different levels of tolerance to environmental factors, such as a pollutant or a shortage of oxygen or nitrates.

Question 16

What is competitive exclusion principle

Answer 16

• the idea that no two species occupy exactly the same niche.
• This is known as the competitive exclusion principle.

Question 17

In the following passage, state the word that best replaces each of the numbers in brackets.

The study of the interrelationships between organisms and their environment is called (1). An ecosystem is a more or less self contained functional unit made up of all the living or (2) features and non-living or (3) features in a specific area. Within each ecosystem are groups of different organisms, called a (4), which live and interact ina particular place at the same time. A group of organisms occupying the same place at the same time is called a (5), and the place where they live is known as a (6). The population size of a species that an ecosystem can support is known as (7).

Answer 17

1) ecology
2) biotic
3) abiotic
4) community
5) population
6) habitat
7) the carrying capacity