1. Unit II: Ecology
Chapter 4: The Organization of Life 4-1 Ecosystems: Everything is Connected

2. Ecosystem: all the organisms living in an area and their physical environment
Made of many interconnected parts (soil washes away, animals migrate, pollen moves)
Often connected in complex ways

3. The Components of an Ecosystem
Biotic vs. Abiotic Factors
Biotic = living (plants, animals, dead organisms, organism’s waste products)
Abiotic = nonliving (air, water, rocks, sand, light, temperature)

4. Habitat: the place an organism lives
Organism: an individual living thing (you, an ant, an ivy plant, a bacterium)
Species: a group of organisms that are closely related and that can mate to produce fertile offspring
Population: all the members of the same species living in the same place at the same time (all the field mice in a corn field)
Community: a group of populations (different species) that live in the same place and interact with each other (ex. Pond Community – all of the populations of plants, fish, and insects that live in and around the pond)
Habitat: the place an organism lives

6. 4-2: Evolution
Evolution: a change in genetic characteristics of a population from one generation to the next
Natural Selection: unequal survival and reproduction due to the presence or absence of particular traits

7. Evolution by Natural Selection
Genetic Diversity: organisms differ in the traits they have and these traits are passed on (at least partly) to their offspring
Overproduction of Offspring (organisms produce more offspring than can possibly survive)
Competition (the environment is hostile and contains limited resources)
Survival and reproduction of the “fittest” (some inherited traits provide organisms with an advantage)
Adaptation: inherited trait that increases an organism’s chance of survival and reproduction in a certain environment
Changing Population (each generation contains proportionately more organisms with advantageous traits)

9. Coevolution: 2 species evolving in response to long-term interactions with each other (ex. beaks within hummingbird populations have become longer as the populations of flowers that they pollinate have become longer)
Artificial Selection: the selective breeding of domesticated plants and animals by humans for specific characteristics (ex. breeds of dog, humans saved the seeds of the largest, sweetest fruits and most nutritious grains)

10. Evolution of Resistance
Resistance: the ability of 1 or more organism to tolerate a particular chemical designed to kill it (an organism may be resistant to a chemical when it contains a gene that allows it to break the chemical down into harmless substances)
We have unintentionally selected for resistance with:
Many illnesses (bacteria) are becoming resistant to antibiotics.
Many insects are becoming resistant to pesticides (chemicals used to kill insects).

11. Pesticide Resistance
A pesticide is sprayed on corn to kill grasshoppers.
Most grasshoppers die, but a few survive.
The survivors happen to have a gene that protects them from the pesticide.
Surviving grasshoppers pass on the gene to their offspring.
Each time the corn is sprayed, the grasshopper population changes to include more and more resistant members.
After many sprayings, the entire population may be resistant, making the pesticide useless.
The faster an organism reproduces, the faster its populations can evolve.

12. 4-3 The Diversity of Living Things Six Kingdoms of Living Things: 1
4-3 The Diversity of Living Things Six Kingdoms of Living Things: 1. Archaebacteria
Characteristics
Single celled; no nucleus; asexual reproduction (divide in ½); found in harsh environments
Important for breaking down dead organisms and recycling nutrients.
Examples
Methanogens (live in swamps and produce methane gas) and extreme thermophiles (live in hot springs)

13. 2. Eubacteria Characteristics
Single celled; no nucleus; asexual reproduction (divide in ½); incredibly common
Important for breaking down dead organisms and recycling nutrients.
Examples
Protobacteria (common in soils and in animal intestines)
Cyanobacteria (also called blue-green algae)
E. coli under a microscope

14. 3. Protists Characteristics
Most single celled – some multi-celled; most live in water
Algae: Plant-like protists (seaweed, pond ‘scum”) make their own food from sunlight
Are the initial source of food in most aquatic ecosystems
Examples
Algae; diatoms; dinoflagellates (red tide), amoeba, paramecia, Euglena

15. 4. Fungi Characteristics
Absorb their food through their body surface; have cell walls; most live on land
Important for breaking down dead organisms and recycling nutrients
Examples
Yeast, mushrooms, molds, mildews, and rusts

16. 5. Plants Characteristics
Multi-cellular, make their own food by photosynthesis; have cell walls
Examples
Ferns, mosses, trees, herbs, grasses
Gymnosperms: evergreen plants, many have cones
Conifer= type of gymnosperm (ex. pine tree)
Angiosperm: flowering plants have seeds in fruit (most plants you see)
Make up most of the food animals eat (wheat rice, beans, oranges, lettuce)
Make building materials and fibers (oak and cotton)

17. 6. Animals Characteristics
Multi-cellular; no cell walls; ingest their food; live on land and in water
Insects:
Most successful animals on Earth
Affect humans in both positive and negative ways.
Examples
Corals, sponges, worms, fish, reptiles, birds, mammals
Invertebrates: no backbone (insects, worms, jellyfish, oysters, squid, etc.)
Vertebrates: have a backbone (fish, amphibians, reptiles, birds, mammals)