Chapter 4

The Organization of Life

“When we try to pick out anything by itself, we find it hitched to

everything else in the universe.”

- John Muir

4.1 Do Now

Ecosystems• Communities of organisms and their

abiotic environment.– Examples: oak forest or coral reef.

• No clear boundaries. • Things move from one ecosystem to

another. – Pollen can blow from a forest into a field, – soil can wash from a mountain into a lake, – birds migrate from state to state.

Components of an Ecosystem

1.Energy (sun)

2.Mineral nutrients

3.Carbon Dioxide

4.Water

5.Oxygen

6.Living Systems• One change can disrupt the entire

ecosystem

Biotic and Abiotic Factors

Biotic• environmental factors that

are associated with or results from the activities of living organisms– plants, animals, dead

organisms, and the waste products of organisms.

Abiotic• environmental factors that

are not associated with the activities of living organisms– air, water, rocks, and

temperature.

Levels of Organization

Levels of Organization

• Biosphere– Area of the Earth

where there is life

• Ecosystem– All of the living and

non-living things in an area

• Community– All of the living things

in an area

• Population– All of the living things

of one species in one area

– Species: group of organisms that can reproduce together

• Organism– An individual

Habitat• Habitat: place where an organism usually

lives.• Has specific characteristics that the

organisms that live there need to survive.– If any of these factors change, the habitat

changes.• Organisms tend to be very well suited to

their natural habitats• Niche: an organism’s role in the ecosystem

– food it eats, what eats it, where it lives

Do Now

• Check the gradesheet being passed around

• Compare your grade with and without the test and decide which quarter you want it for

• Turn in your written section- if you don’t turn it in it’s a zero (counts for quarter 2)

4.2 Do Now

Do Now

• Just think about it…• If you could have one super adaptation,

what would it be?

Charles Darwin• Observed that organisms in a

population differ slightly from each other in form, function, and behavior.– Some of these differences are

hereditary.• Proposed that the environment

exerts a strong influence over which individuals survive to produce offspring, and that some individuals, because of certain traits, are more likely to survive and reproduce than other individuals.

Evolution by Natural Selection• Natural selection: process by which

individuals that have favorable variations and are better adapted to their environment survive and reproduce more successfully than less well adapted individuals do.

• Evolution: is a change in the characteristics of a population from one generation to the next.

So how does Natural Selection actually work?

Evolution by Natural EvolutionAll of the following must occur in order for Natural Selection to take place

Nature Selects• Adaptation: an anatomical, physiological,

or behavioral change that improves a population’s ability to survive.

Do Now• How did THIS happen?

Coevolution• Coevolution: The

process of two species evolving in response to long-term interactions with each other– Example: Hawaiian

honeycreeper

Evolution by Artificial Selection• Artificial selection: selective breeding of

organisms, by humans, for specific desirable characteristics.– Dogs– Fruits, grains,

and vegetables– Livestock

Evolution of Resistance• Resistance: the ability of an organism to tolerate a

chemical or disease-causing agent.• An organism may be resistant to a chemical when it

contains a gene that allows it to break down a chemical into harmless substances.– Pesticides– Antibiotics

Homework

• Begin writing descriptions of adaptations, environment, and natural selection

• Project will be presented on Tuesday

4.3 Do Now

The Diversity of Living Things• Classified into 3 Domains with 6 Kingdoms

The Kingdoms of Life

Domain Eukarya

Domain Eubacteria

Domain Archaea