Open Book to page 123Answer the following questions:

Bellringer

Write a paragraph that describes YOUR habitat. Describe how you obtain food, water, and shelter from your habitat. How does your habitat meet your needs in ways that other habitats do not. TURN YOUR ARTICLE IN TO THE STICKER

BOX

TURN YOUR ARTICLE IN TO

THE STICKER BOX

Environmental Science

Chapter 4:Population Ecology

Chapter 4: Population Ecology

This week’s Goals and Objectives:1. Describe the different levels of organizations studied by ecologists.2. Explain the difference between biotic and abiotic factors. Give

examples.3. Discuss how an organisms habitat relates to its survival.4. Discuss the usefulness of tracking population size.5. Describe the three ways populations can be distributed.6. Explain what age structure diagrams tell you about a population.7. Describe the factors that influence a population’s growth rate.8. Explain exponential growth and logistic growth. 9. Explain how limiting factors and biotic potential affect population

growth.

SIGN IN

Chapter 9: Surface Water

Answer and Turn in today!1. Describe how surface water can move eroded materials.2. Explain how a stream carries its load.3. Describe how a floodplain develops.4. Describe the physical features of stream development5. Describe the relationship between meanders and stream flow6. Explain the process of rejuvenation in the development of a

stream.7. Explain the formation of lakes and wetlands8. Describe the process of eutrophication9. Recognize the effects of human activity on lake development.

SIGN INGet an environmental science book (FROG on it)1. Do the following questions…DO NOT

WRITE the question, only the answers

1. Page : 103 questions: 1,2,32. Page : 109 questions: 1,3,43. Page : 117 questions: 1,2,34. Page : 122 questions: 17-21, 26TURN IT IN TODAY

SIGN INGet an EARTH SCIENCE book: Chapter 91. Do the following questions…DO NOT

WRITE the question, only the answers

1. Page : 231 questions: 1-42. Page : 237 questions: 1-33. Page : 241 questions: 1-34. Page : 245 questions: 1-75. Page : 247 questions: 30-35TURN IT IN TODAY

What is ecology?

The study of how organisms interact with each other and with their environments W

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Defining an ecosystem

Ecosystem: all the organisms living in an area together

Forest Ecosystem

Pond Ecosystem Vacant Lot

Ecosystem Desert

Ecosystem

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All Ecosystems are connected

How does your ecosystem impact the Atlantic Ocean?

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Parts of an ecosystem

In order for an ecosystem to survive there must be certain basic parts

Energy Mineral nutrients Carbon dioxide Water Oxygen and more

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Biotic vs. Abiotic

Biotic: living parts of the ecosystem

Plants, animals, bacteria, etc.

Abiotic: nonliving parts of the ecosystem

Sunlight, soil, air, temperature

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Organizing Biotic Parts

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smallest

largest

Smallest Unit

Organism: an individual living thing like you, a tree, a fox, a rose

Species are groups of organisms

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Species Species: groups of

organisms that resemble each other in:

1. appearance2. Behavior3. Chemistry4. genetic makeup5. able to reproduce

VIABLE offspring3.6 to 100 million species

(1.4 identified)

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Population

Population: all the members of the same species that live in the same place at the same time

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Community

Community: a group of various species that live in the same place and interact with each other.

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Ecosystem

Ecosystem: all the organisms living in an area together W

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Biosphere

All parts of the Earth where life is found

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HabitatHabitats provide

an organism with resources—anything an organism needs to survive and reproduce, including food, shelter, and mates.

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Review: What is a population?

Population: all the members of the same species that live in the same place at the same time

Field mice living in a corn field, grizzly bears of Yellowstone Park area

Wolves in Yellowstone NP

Population Size

Why care about the size of the population?

How can scientists estimate the population (say of Elephant Seals on a beach in CA)?

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Population Size• The number of

individuals in a population at a given time

• Sudden and dramatic decreases in population size can indicate an unhealthy population headed toward extinction.

• Ecologists often use sampling techniques to estimate population size.

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Estimating PopulationHow can you estimate the population of trees in this valley?

WHY NOT COUNT THEM ALL?

WHY IS SAMPLING NEEDED?

Population Density•Measure of how crowded a population is

• Larger organisms generally have lower population densities.

• Low population density: More space, resources; finding mates can be difficult

• High population density: Finding mates is easier; tends to be more competition; more infectious disease; more vulnerability to predators

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Population DistributionHow organisms are arranged within an area:

UNIFORM

RANDMOM

CLUMPEDOccurs where resources needed are found throughout, wildflowers in meadow

Occurs when individuals hold territory or compete for space. Plants in desert

Most Common. Occurs where resources are together. Water hole in desert, humans in cities

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Population Distribution

•Uniform distribution: Organisms evenly spaced

•Random distribution: Organisms arranged in no particular pattern

•Clumped distribution: Organisms grouped near resources; most common distribution in nature

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Sex Ratios• Proportion of

males to females

• Age structure diagrams give information about sex ratios.

• For a monogamous species, the ideal sex ratio is 50:50.

Why is 50/50 not as important in non-monogamous populations?

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Survivorship

Individuals of different ages have different probabilities of dying

Survivorship curves show how the likelihood of death varies with age.

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Page 111 in Frog Book

Type I survivorship curves are for species that have a high survival rate of the young, live out most of their expected life span and die in old age. Humans are a good example of a species with a Type I survivorship curve

Type II survivorship curves are for species that have a relatively constant death rate throughout their life span. Death could be due to hunting or diseases. Examples of species exhibiting a Type II survivorship curve are coral, squirrels, honey bees and many reptiles.

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Type III survivorship curves are found in species that have many young, most of which die very early in their life. Plants, oysters and sea urchins are examples of species that have Type III survivorship curves.

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Patterns of GrowthEXPONETIAL GROWTH

• Population increases by a fixed percentage every year.

• Normally occurs only when small populations are introduced to an area with ideal environmental conditions

• Rarely lasts long

WHAT SHAPE DOES EXPONENTIAL GROWTH LOOK LIKE?

Starts slowly, then takes off – “J-Shaped Curve”

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Limiting FactorsLimiting Factor

Principle: too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are near or above optimum.

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Carrying Capacity

Limiting Factors lead to Carrying Capacity: the largest population an environment can sustain.

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Biotic Potential•An organism’s maximum ability to produce offspring in ideal conditions

•Many factors influence biotic potential, including gestation time and generation time.

•Organisms with high biotic potential can recover more quickly from population declines than organisms with low biotic potential.

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Open Book to page 122Answer questions

17-2325-26

Class work