Lesson #1: Introduction

Question 1

Ecology

Answer 1

Ecology is the branch of biology that deals with the study of the interactions
among organisms and with their environment.

Scientists who study ecology are called ecologists.

Because our planet is so diverse, ecologists tend to study smaller areas called
ecosystems.

Question 2

Ecosystems

Answer 2

An ecosystem consists of the physical environment, and all the living things
within that environment.

Abiotic Factors: these are the non living things that make up the physical
environment.

Examples: water, atmosphere, soil, temperature

Biotic Factors: these are the living things within the physical environment.

Examples: plants, animals, fungi and bacteria

Question 3

Types of Ecosystems

Answer 3

Ecosystems can be extremely small or extremely large. They can all be
classified into one of two categories:

Terrestrial Ecosystem

An ecosystem contained on land

Located on continents of islands, water is a limiting factor

Aquatic or Marine Ecosystem

An ecosystem contained in water

Freshwater – lakes and rivers

Saltwater/Marine – oceans

Question 4

Trophic Levels

Answer 4

All living things have a part to play in the function of an ecosystem. These roles
are defined by trophic level.

The trophic level of an organism is defined by the energy and nutrients it
contributes, consumes or recycles within the ecosystem.

Question 5

Autotrophs and
Heterotrophs

Answer 5

All organisms need a supply of nutrients (carbon compounds such as
glucose). There are two methods for obtaining these nutrients:

Autotrophs – create their own carbon compounds from carbon dioxide in the atmosphere and other simple substances such as water. Often called producers.

Heterotrophs – obtain carbon compounds from other organisms. Often called consumers.

Some organisms use both
methods. These are unicellular organisms such as Euglina.

Question 6

Roles in Ecosystems

Answer 6

Autotrophs

Producers - plants and algae trap the energy in sunlight and convert that energy
to carbohydrates.

Heterotrophs

Primary Consumers - cannot make their own energy, and must obtain energy
from producers.

Secondary Consumers – cannot make their own energy and must obtain energy from primary consumers.

Tertiary Consumers – cannot make their own energy and must obtain energy
from secondary consumers.

Omnivores – organisms that feed on BOTH producers and consumers.

Question 7

More Complicated Roles

Answer 7

Detritivores – heterotrophs that obtain nutrients from detritus by internal digestion.

Decomposers - consume dead plant and animal remains and convert them into substances that can be reused.

Examples: earthworms

Scavengers – eat dead animal remains in order to obtain energy.

Examples: vulture and hyena.

Saprotrophs – heterotrophs that obtain nutrients from dead organic matter by external digestion.

Examples: bacteria and fungi