1. INTERACTIONS IN THE ECOSYSTEM
CHAPTER 5
Define Ecosystem.

2. Habitats and Niches
Every organism is adapted to life in the habitat or ecosystem in which it lives
The role of an organism in the ecosystem is called its niche (pronounced neesh)
Niche made up of:
abitoic factors: sunlight, temperature, water
biotic factors: food source, position in the food chain, etc
Describe the niche of a deer in Jackson county.

3. More About Niches Describe your niche.
Competitive Exclusion - the extinction of a species due to direct competition for the same resources.
The species that is better at getting the resources will force the other species to leave, change their niche or die
Niche diversity is determined by the abitotic factors in a habitat
Describe your niche.
Describe your niche.

4. Predator/Prey
A predator is an organism that hunts other organisms for food (prey)
Predators can be a limiting factor in niche diversity
Keystone Predator - A predator that causes a large increase in habitat diversity (Ex: a seastar in a tidepool
Are there many natural deer predators in this area?
Are there many natural deer predators in this area?

5. Evolution and Adaptation
Ecosystems change over time
All species adapt to niches in their environment
The way many populations respond to environmental changes is by evolving or changing in response to changes in their environment.
Why is there little ongoing evolutionary proof?
Why is there little ongoing evolutionary proof?

6. Evolution and Adaptation
Evolution is defined as a change in a population of organisms over time Organisms have three options in response to changes in the environment:
adapting to different niches in the same habitat to avoid competing for the same resources
move to a new habitat to avoid competition
die (and possible extinction)
Why are so many animals extinct from years ago?
Why are so many animals extinct from years ago?

7. Convergent Evolution Convergent Evolution
Similar ecosystems often have similar niches. Organisms from both ecosystems will also have similar adaptations
Ex: Wings on a bee, a bird and a bat. The insect wing, bird wing and mammal wing all serve the same purpose but are very different on each organism. Sharks (fish) and dolphins (mammals) look similar, both have fins, but their bodies are very different in structure.
What example of convergent evolution is in the book?
What example of convergent evolution is in the book?

8. Coevolution Species that are dependant on and adapt to suit each other
Monarch caterpillar eats only poisonous milkweed leaves – which make the adult butterfly poisonous to its predators.
Acacia tree and ants - the trees have sharp thorns - provide ants with both food and a place to build their nests. Ants keep other insect pests away from the trees.
What example of convergent evolution is in the book?
What example of convergent evolution is in the book?

9. Populations
The size of the population of any organism is dependent on the abiotic and biotic factors that shape each niche.
Population size changes as the conditions in the niche change.
Thomas Malthus (1798) studied human populations
Charles Darwin (1859) studied plant and animal populations

10. Populations
Exponential Growth – the growth rate of each generation is a multiple of the parent generation
Plants: corn, rice, wheat, oak trees
Animals: like sea turtles, alligators, mice, spiders, goldfish, robins, dogs and cats
All have many babies – not all
babies survive to become
adults.

11. Growth Rate Darwin – noticed that most organisms produce
many more offspring than will
Actually survive into adulthood (some babies do die)
Abiotic factors like water and
land (space) limit population
size and reproduction rate
Do you think Darwin was right? Why or why not?
Do you think Darwin was right? Why or why not?

12. Population Size
Carrying Capacity – The number of individuals in any species that can be successfully supported by their ecosystem.
Ex: The number of lynx
that survive the Arctic winter
depends on the number
of snowshoe hare that
available to eat.
Black bears in NJ have exceeded
the carrying capacity of the forest

13. Populations Limiting Factors – The forces
that slow the growth in any population
Density-Dependent factors:
predators, food, disease
Density-Independent factors:
water, climate, living space,
natural disasters,
human disturbance

14. Limiting Factors
Elephants are limited in population growth because the resources like water, food and land are limited in their African savanna habitat.
There is a long dry season (with no rain) followed by a shorter rainy season.
Elephants eat many tons of plants each day and need a lot water to drink and cool themselves with.
Only one female in each family has a baby – the rest of the females help care for the young
How is our population controlled like the elephants?
How is our population controlled like the elephants?

15. CHAPTER 5 VOCABULARY (You Should Know)
Niche
Limiting factor
Keystone Predator
Prey
Evolution
Extinction
Convergent evolution
Adaptation
Coevolution
Evolve
Exponential Growth
Habitat
Carrying Capacity
Ecosystem
Competitive Exclusion
Migration
Write a sentence using each word.
Write a sentence using each word.

16. Changes in Florida
Humans lived alongside mammoths, mastodons and giant sloths 13,000 years ago in the area now known as Vero Beach, Florida. What two factors are blamed for their extinction?
Humans lived alongside mammoths, mastodons and giant sloths 13,000 years ago in the area now known as Vero Beach, Florida. What two factors are blamed for their extinction?