1.1. Populations and ecosystems

Question 1

Define Ecology

Answer 1

The study of the biosphere, and of interrelationships between organisms and their environment.

Question 2

Define Biosphere

Answer 2

The life-supporting layer of land, air and water that surrounds the Earth.

Question 3

Define Abiotic factor

Answer 3

An ecological factor that makes up part of the non-living/non-biological environment of an organism.

Question 4

Define Biotic factor

Answer 4

An ecological factor that makes up part of the living/biological environment of an organism.

Question 5

Define Ecosystem

Answer 5

A more or less self-contained functional unit in ecology made up of all the interacting biotic and abiotic factors in a specific area.

Question 6

2 major processes within ecosystems?

Answer 6

• Flow of energy through ecosystem

- Cycling of elements within ecosystem

Question 7

Ecosystem made up of?

Answer 7

Many different species

Question 8

Define Species

Answer 8

A group of genetically similar organisms that can breed to produce fertile offspring.

Question 9

Species made up of?

Answer 9

Many populations

Question 10

Define Population

Answer 10

A group of interbreeding organisms of the same species that occupy the same habitat at the same time.

Question 11

Why are boundaries of a population difficult to define? (2)

Answer 11

• In theory - any 2 members of the same species can interbreed
• In practise - long distance makes interbreeding unlikely, considered separate populations

Question 12

Populations of different species form?

Answer 12

A community

Question 13

Define Community

Answer 13

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

Question 14

Define Habitat

Answer 14

The place where an organism normally lives, which is characterised by physical conditions, and the species of other organisms present.

Question 15

Define Microhabitat

Answer 15

A smaller unit within a habitat, each with its own microclimate.

Question 16

Define Ecological niche

Answer 16

All conditions and resources required for an organism to survive, reproduce and maintain a viable population.

Question 17

No 2 species occupy…

Due to differences in? (4)

Answer 17

…exactly the same niche

• Behaviour - nesting habits
• Tolerance of environmental factors - pollution/shortage of O2 or N2

Question 18

EXAM QUESTION

Ecologists studies a community of fish in a lake.

Explain what is meant by a community.

Answer 18

All the fish/all the species/all the

populations/all the organisms;

Question 19

EXAM QUESTION

The ecologists found that each species of fish had adaptations to its niche. One of these adaptations was the shape of its mouth.

Suggest how the shape of mouth is an adaptation to its niche.

Answer 19

1. With different mouth eats
different food / has different way
of feeding / specific mouth shape
for specific food;
2. Competition between
species/interspecific competition
is reduced;

Question 20

EXAM QUESTION

The position of the tree line is determined by abiotic factors.

What is meant by an abiotic factor?

Answer 20

Non-living/physical/chemical

factor/non biological;