1. Ecology
Chapter 2

2. Ecology - The study of interactions that take place between organisms and their environment

3. Levels of Ecological Organization
Organism – an individual living thing
Species – a group of very similar organisms that can interbreed and produce fertile offspring
Hybrids are not species
Examples
Ligers
Mules

4. Levels of Ecological Organization
Population – organisms of the same species that live in the same place and at the same time
Community – different populations of different species that live in the same place at the same time
Ecosystem – a community of living organisms plus their non-living environment
Biosphere – all the combined ecosystems of the world where organisms can live

6. Biotic vs. Abiotic Biotic factors – living organisms in an ecosystem
Examples:
Bee
Dandelion
Oak tree
Deer
Abiotic factors –
non-living parts of an ecosystem
Examples
Water
Air
Soil
Rocks

7. Ecological Relationships
Niche – an organism’s role in its ecosystem
Habitat – the place where an organism lives
Example
Lion’s niche and habitat

8. Ecological Relationships
Predator-Prey
Predator – an animal that captures and eats a member of another species
Prey – an animal that is subject to being caught and eaten

9. Ecological Relationships
Herbivore – an animal that eats only plants
Carnivore – an animal that only eats other animals
Omnivore – an animal that eats plants and animals

10. Ecological Relationships
Competition – the conflict between organisms when they try to use the same resources at the same time
Some resources
Food
Mating
Habitat

11. Ecological Relationships
Symbiosis – living together
Symbiotic Relationships (involves two species)
Mutualism – both species benefit
Ex. – Insect and flower

12. Ecological Relationships
Symbiotic Relationships
Commensalism – only one species benefits but the other is neither helped nor harmed
Ex. – Whale and barnacle

13. Ecological Relationships
Symbiotic Relationships
Parasitism – one organism benefits at the expense of another organism
Ex. Tick and dog
Cuckoo
Brood parasite

15. Energy Flow in Ecosystems
Producers (or autotrophs) – organisms that make their own food usually by using energy directly from the sun
Ex. - plants
Consumers (or heterotrophs) – organisms that cannot make their own food and must get energy by eating producers or other consumers
Ex. - animals

16. Energy Flow in Ecosystems
Decomposers (or saprotrophs) – organisms that obtain nutrients by breaking down dead and decaying plants and animals
Scavenger – organisms that eat dead or decaying organisms
Primary consumer – eats producers
Secondary consumer – eats a primary consumer
Tertiary consumer – eats a secondary consumer
Quaternary consumer – eats a tertiary consumer

17. Energy Flow in Ecosystems
Food chain – a simple representation of how energy is passed from a producer to consumers

19. Energy Flow in Ecosystems
Food web – a more complex representation of how energy is passed from producers to consumers in an ecosystem

21. Energy Flow in Ecosystems
Trophic level – organism that represents a feeding step
Energy pyramid – a representation in the shape of a pyramid that shows how energy is passed from one trophic level to the next

22. Energy Flow in Ecosystems
Most energy is located at the producer level
As the trophic level increases, 10% of energy is lost

23. Ecological Succession
Ecosystems are constantly changing.
Ecological succession – a gradual process of change and replacement of the types of species in a community.

25. Primary Succession
Primary succession – a type of succession that occurs on a surface where no ecosystem existed before
Example: Hawaii islands

26. Primary Succession
Pioneer species – a species that colonizes an uninhabited area and that starts an ecological cycle in which many other species become established.

27. Primary Succession Lichen and bacteria are the pioneer species
Mosses are usually the second organisms to form

29. Secondary Succession
Secondary succession occurs on a surface where an ecosystem has previously existed.
Secondary succession can occur in ecosystems that have been disturbed or disrupted by humans, animals, or by natural process such as storms, floods, earthquakes, or volcanic eruptions.

30. Secondary Succession
Climax community – the final, stable community in equilibrium with the environment

31. Climax community

32. Secondary Succession
Old-field succession is a type of secondary succession that occurs when farmland is abandoned.
When a farmer stops cultivating a field, grasses and weeds quickly grow and cover the abandoned land.
Over time, taller plants, such as perennial grasses, shrubs, and trees take over the area.