1. Living Things in Ecosystems

2. Everything is connected…

3. What is an Ecosystem?
Includes all the different organisms living in a certain area, along with their physical environment
Biotic Factors – the living parts of an ecosystem
The animals, plants and microorganisms
Abiotic Factors – the nonliving parts of the ecosystem
Temperature, sunlight, water, soil, etc.

4. Levels of Organization
Organism – one individual living thing
Species – a group of organisms that are able to produce fertile offspring
Population – a group of individuals of the same species living the same place
Community – a group of interacting populations of different species

5. Levels of Organization

6. Niche and Habitat Habitat – the actual place where an organism lives
Lion – savanna
Cactus - desert
Niche – an organism’s way of life
When and how often an organism reproduces
What time of day it’s most active
What it eats and what eats it

7. Evolution by Natural Selection
Charles Darwin proposed his theory of natural selection to explain how organisms adapt to their environment
Natural selection – the unequal survival & reproduction that results from the presence or absence of certain traits
Evolution – the change in the traits of populations from one generation to the next

8. Evolution by Natural Selection

9. Darwin’s Theory
All organisms produce more offspring than can possibly survive
The environment contains things that kill organisms (struggle to survive)
Individuals vary, or differ, in their traits
Some variations give an organism an advantage
Those with advantages survive and have more offspring

10. Evolution by Natural Selection

11. Coevolution When two or more species evolve in response to each other
Snails developed thicker shells, so crabs evolved stronger claws
Plants produce poisonous chemicals, herbivores evolved the ability to detoxify these chemicals

12. Adaptation
An inherited trait that increases an organism’s chance of survival and reproduction in a certain environment.

13. Artificial Selection
The selective breeding of organisms by humans for specific characteristics.
Fruits, grains and veggies too = shape, size, sweetness, visual appeal

14. Resistance
The ability of one or more organisms to tolerate a particular chemical designed to kill it.
Bacteria
Insects
Humans, etc.

15. Species Interactions
Ways in which the biotic components affect each other…
Predation
Competition
Parasitism
Mutualism
Commensalism

16. Predation One organism kills and eats another organism
Prey – the organism that is eaten
Predator – the one that does the eating

17. Predation The predators and prey affect each other’s population
↑ prey → ↑ predator → ↓ prey → ↓ predator

18. Competition
When two or more organisms of the same or different species attempt to use the same limited resource
Hyenas competing with lion’s for an animal carcass
Ants fighting for territory
Birds competing for a mate
Flowers competing for pollinators

19. Competition

20. Parasitism
When one organism benefits from the relationship and the other is harmed
Parasite – organisms that live in or on another organisms and feed on it
Tick, flea, tapeworm
Host – the organism the parasite takes its nourishment from
Parasites will not usually kill their host

21. Parasitism

22. Mutualism
A relationship between two organisms in which both organisms benefit
The bacteria in your intestines
Insects and flowers

23. Commensalism
A relationship in which one species benefits and the other is neither harmed nor helped