1. Ecology
The study of the interactions that take place among organisms and their environment
ENVIRONMENT – living and non-living components
ABIOTIC – non-living component or physical factors as soil, rainfall, sunlight, temperatures
BIOTIC – living component are other organisms.

2. Biosphere The part of Earth that supports life
Top portion of Earth's crust
All the waters that cover Earth's surface
Atmosphere that surrounds Earth.

4. Ecosystem
All the organisms living in an area and the nonliving features of their environment

6. Energy and organisms
Autotrophs
Organisms which can synthesise their own complex, energy rich, organic molecules from simple inorganic molecules (e.g. green plants synthesis sugars from CO2 and H2O)
Heterotrophs
Organisms who must obtain complex, energy rich, organic compounds form the bodies of other organisms (dead or alive)

7. Detritivores
Heterotrophic organisms who ingest dead organic matter. (e.g. earthworms, woodlice, millipedes)
Earth worm
(Lumbricus terrestris)

8. (Cantherellus cibarius)
Saprotrophs
Heterotrophic organisms who secrete digestive enzymes onto dead organism matter and absorb the digested material. (e.g. fungi, bacteria)
Chanterelle
(Cantherellus cibarius)

9. Species
A group of organisms that can breed to produce fully fertile offspring
Population
All the organisms in an ecosystem that belong to the same species

10. The characteristics of populations are shaped by the interactions between individuals and their environment
Populations have size and geographical boundaries.
The density of a population is measured as the number of individuals per unit area.
The dispersion of a population is the pattern of spacing among individuals within the geographic boundaries.

11. Population Dynamics Characteristics of Dynamics Size Density Dispersal
Immigration
Emigration
Births
Deaths
Survivorship

12. Parameters that effect size or density of a population:
Immigration
Birth
Population (N)
Death
Emigration
The size of a population is determined by a balance between births, immigration, deaths and emigration

13. Introduction Why do all populations eventually stop growing?
What environmental factors stop a population from growing?
The first step to answering these questions is to examine the effects of increased population density.

14. Density-Dependent Factors
limiting resources (e.g., food & shelter)
production of toxic wastes
infectious diseases
predation
stress
emigration

15. Density-Independent Factors
severe storms and flooding
sudden unpredictable severe cold spells
earthquakes and volcanoes
catastrophic meteorite impacts

16. Density-dependent factors
increase their affect on a population as population density increases.
This is a type of negative feedback.
Density-independent factors are unrelated to population density, and there is no feedback to slow population growth.

17. INTERACTIONS AMONG SPECIES
Interspecific competition
Predation
Exploitation
Symbiosis

18. Types of Species Interactions
Neutral – two species do not interact
Mutualism – both benefit
Commensalism – one benefits, other neutral
Parasitism – one benefits, one harmed
but not killed
Predation – one benefits, other killed

19. Community All the populations in an ecosystem Limiting Factors
Any abiotic or biotic factor that restricts the numbers, reproduction, or distribution of organisms.

21. Communities Range of Tolerance
The limits within which an organism can exist.

22. Biodiversity What is Biodiversity?
The variety of life in an area that is determined by the number of different species in that area.
There are 2 main types:
Genetic Diversity
Species Diversity

23. Habitat The place in which an organism lives
provides the kinds of food and shelter, the temperature, and the amount of moisture the organism needs to survive

24. The place of an organism in its environment
Niche An organism’s habitat + role + tolerance limits to all limiting factors
THE COMPETITIVE EXCLUSION PRINCIPLE
G.F. Gause (1934) If two species, with the same niche, coexist in the same ecosystem, then one will be excluded from the community due to intense competition

25. Niche The niche of a species consists of:
Its role in the ecosystem (herbivore, carnivore, producer etc)
Its tolerance limits (e.g. soil pH, humidity)
Its requirements for shelter, nesting sites etc, all varying through time

26. Separate niches Species B Species A No overlap of niches.
So coexistence is possible

27. Overlapping niches Species B Species C
Interspecific competition occurs where the niches overlap

28. Specialisation avoids competition
Species B
Species C
Evolution by natural selection towards separate niches
Species B’
Species C’
Specialisation into two separate niches

29. This niche is not big enough for the both of us!
Species A Species D
Very heavy competition leads to competitive exclusion
One species must go

30. Example: Squirrels in Britain
The Red Squirrel (Sciurus vulgaris) is native to Britain
Its population has declined due to:
Competitive exclusion
Disease
Disappearance of hazel coppices and mature conifer forests in lowland Britain
Isle of Wight Tourist Guide

31. The Alien The Grey Squirrel (Sciurus carolinensis) is an alien species
Introduced to Britain in about 30 sites between 1876 and 1929
It has easily adapted to parks and gardens replacing the red squirrel
Bananas in the Falklands

32. Limits population size
Competition
Competition caused by population growth affects many organisms, including humans
Limits population size

33. Intraspecific competition for food can also cause density-dependent behavior of populations.
Territoriality.
Predation.

34. Feeding relationships
Predators & prey
Herbivory
Parasite & host
Mutualism
Competition
Large blue butterfly
(Maculinea arion)

35. Food Chain Producer 1st order Consumer or Herbivore
rose plant  aphids  beetle  chameleon  hawk
Producer
1st order Consumer or Herbivore
2nd order Consumer or 1st order Carnivore
3rd order Consumer or 2nd order Carnivore
4th order Consumer or 3rd order Carnivore
Decomposers – consume dead and decaying matter

36. Trophic levels
Each step in a food chain or a food web is called a trophic level.
Producers are the first trophic level
Consumers are the second, third, or higher trophic level
Each trophic level depends on the one below for energy