Unit 3 Population Ecology Finding Gold in a

Unit 3: Population Ecology

Finding Gold in a Costa Rican Cloud Forest • Golden toads lived in Costa Rica’s Monteverde cloud forest. • Golden toads were first described in 1964. They were extinct by 1989. Talk About It Why is the extinction of the golden toad a global concern?

Lesson 4. 1 Studying Ecology

Lesson 4. 1 Studying Ecology Levels of Ecological Organization ECOLOGY • _________ - The study of how organisms interact with each other and with their environments • Scientists study ecology at various levels of organization. Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Levels of Ecological Organization INDIVIDUAL • _________ - One organism Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Levels of Ecological Organization POPULATION • __________ - members of a species that live in the same area at the same time SPECIES - a group of individuals that interbreed and • _________ produce fertile offspring • Population Ecology is the study of how individuals within a population interact with one another Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Levels of Ecological Organization COMMUNITY • __________ - All of the populations in a particular area • Community Ecology is the study of interactions between species Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Levels of Ecological Organization ECOSYSTEM • __________ - Includes all of the living things and nonliving things in a particular area • Ecosystem Ecology is the study of the living and nonliving components of a system together Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Levels of Ecological Organization BIOSPHERE • __________ - All parts of Earth that host life, with all its organisms and environments Individual Population Community Ecosystem Biosphere

Lesson 4. 1 Studying Ecology Biotic and Abiotic Factors BIOTIC • ______ factors: Parts of an ecosystem that are ______ or used to be living LIVING • Examples: • Plants • Animals • Fungus • Bacteria Did You Know? Decaying organisms are biotic factors as long as their structure remains cellular.

Lesson 4. 1 Studying Ecology Biotic and Abiotic Factors ABIOTIC • ________ factors: Parts of an ecosystem that have never been living • Examples: • Sun (Sunlight) • Oxygen • Water • Rocks • Temperature • Wind • p. H

Lesson 4. 1 Studying Ecology Habitat • _______ -The specific environment in which an organism lives • Includes biotic and abiotic factors ORGANISM • Boundaries are defined by the particular ________ that lives there • Earthworm vs. Hawk

Lesson 4. 1 Studying Ecology Habitat RESOURCES • Habitats provide an organism with __________ —anything an organism needs to survive and reproduce, including food, shelter, and mates.

Lesson 4. 2 Describing Populations From 1900 to 2000, the white-tailed deer population of New York state grew from about 20, 000 to more than 1 million. Densities of more than 100 deer per sq mi occur in some metropolitan areas.

Lesson 4. 2 Describing Populations Population • What is a population again? • SPECIES Members of the same _______ that live in AREA TIME the same ______ at the same _______ • Population ecology studies how members of the population interact with one another

Lesson 4. 2 Describing Populations Population Size NUMBER • Population Size -The _______ of individuals in a population at a given time • When population size __________ or remains ______, it is a sign that the population is healthy • Sudden and dramatic __________ in population size can indicate an unhealthy population headed toward extinction. • Ex. Golden Toads • 1987 – 1500 toads • 1988 – 10 toads • 1989 – 1 toad • 1990 – no toads STEADY INCREASES DECREASES

Lesson 4. 2 Describing Populations Population Size • The Decline of the Passenger Pigeon • Once the most abundant bird in North America • In the early 1880 s a scientist described a flock of 2 billion birds that covered 240 miles of sky, took 5 hours to pass overhead and sounded like a tornado! • Then, due to deforestation and hunting, the population slowly dwindled away with the last one dying in 1914

Lesson 4. 2 Describing Populations Population Size SAMPLING • Ecologists often use ________ techniques to estimate population size. • Count organisms in a ________ sample area and use it to estimate how many there are in the larger overall area SMALLER • Ex. If there are 100 oak trees in one square km, it would be reasonable to estimate that there are _____ in ten square kms 1000 Counting Laysan Albatross Nests

Lesson 4. 2 Describing Populations Population Size • What if what you are counting doesn’t stay still? MARK & RECAPTURE • Use the “________________” Technique • Catch organisms, tag them, release them • Catch another sample of organisms • Assume that the number of marked organism that are recaptured in the sample is proportionate to the number of marked organisms in the whole population • # marked in sample = # marked in total population ____# in sample # population

Lesson 4. 2 Describing Populations Population Size • Ex. Suppose you capture and mark 20 turtles at a pond. After releasing these turtles, you return a few days later and catch 10 turtles. Of these 10 turtles, 5 are already marked. How many turtles are in the total population? • # marked in sample = # marked in total population ____# in sample # population • 5 = 10 • 5*? = (20)*(10) • 5*? = 200 • ? (# population) = 40 20 ?

Lesson 4. 2 Describing Populations Population Density • Measure of how ________ a population is (number of individuals within a population per unit area CROWDED • Ex. If 1500 golden toads were found within 4 square kilometers, the population density would be _____ or _______ toads/square km. 375 1500/4 • Larger organisms generally have lower population densities (ex. Lions).

Lesson 4. 2 Describing Populations Population Density LOW • ____ population density: More space and resources but finding mates can be difficult

Finding a mate can be difficult with a low population density

Lesson 4. 2 Describing Populations Population Density HIGH • _____ population density: Finding mates is easier but there tends to be more __________, more infectious _______, & more vulnerability to predators COMPETITION DISEASE • Ex. Harlequin Frog Northern pintail ducks

Lesson 4. 2 Describing Populations Population Distribution ARRANGED • How organisms are _________ within an area: RANDOM 1) ________ distribution: Organisms arranged in no particular pattern • Resources are found ___________ the area and others organisms do not influence where members of the population settle THROUGHOUT

Lesson 4. 2 Describing Populations Population Distribution UNIFORM 2) ________ distribution: Organisms evenly spaced • Individuals hold territories or ________ for space COMPETE

Lesson 4. 2 Describing Populations Population Distribution CLUMPED 3) ________ distribution: Organisms grouped near __________ • RESOURCES MOST COMMON _____________ distribution in nature

Lesson 4. 2 Describing Populations Age Structure NUMBER • Age Structure Diagram - Relative ________ of organisms of each ____ group within population displayed in a pyramid AGE GROWTH • Can be used to predict future population ________

Lesson 4. 2 Describing Populations Age Structure • Three Main Types of Populations STABLE 1) ________ - Even distribution of ages (births keep pace with deaths) DECLINING ________ - Mostly younger GROWING 2) _________ - Mostly older individuals 3)

Lesson 4. 2 Describing Populations Age Structure

Lesson 4. 2 Describing Populations Sex Ratios MALES FEMALES • Proportion of _______ to ________ • Age structure diagrams give information about sex ratios. 50: 50 • For a monogamous species, the ideal sex ratio is _____. • Why?

Lesson 4. 3 Population Growth From 1800 to today, the human population has grown from about 1 billion to more than 6. 8 billion—an exponential rate of increase.

Lesson 4. 3 Population Growth • A few bacteria can multiply to millions in hours • A few whales must have at least a year to produce just one baby. • Why? ?

Lesson 4. 3 Population Growth • Factors That Determine Population Growth 1)Births and Deaths 2)Immigration and Emigration

Lesson 4. 3 Population Growth Birth and Death Rates • A population’s relative birth and death rates (mortality and natality) affect how it ________. GROWS DENSITY distribution, sex ratio • Population size, _______, and _______ AGE __________ STRUCTURE all influence how many are born and how many die. • If everything else is equal, when a populations birthrate is greater than their death rate, the population ________. INCREASES

Lesson 4. 3 Population Growth Birth and Death Rates • Survivorship curves show the likelihood of death varies with age. • Type I – Higher mortality rate at an OLDER _____ ages Ex. Humans • Type II -EQUAL _____ mortality at all ages Ex. Most birds • Type III – Higher mortality rate at _______ YOUNGER ages Ex. Golden Toad

Lesson 4. 3 Population Growth Immigration and Emigration • In addition to births and deaths, population growth is affected by immigration and emigration ARRIVAL of individuals from outside • Immigration – _______ a give area IN • Emigration - DEPARTURE ________ of individuals from a given area EXIT

Lesson 4. 3 Population Growth Immigration and Emigration • MIGRATION ________ seasonal movement into and out of an area, can temporarily affect population size.

Lesson 4. 3 Population Growth Calculating Population Growth • Determined by the following equation: a (individuals added) – (individuals subtracted) or. . Birthrate Immigration rate) (_________ + _________ - Emigration rate) Death rate + ________ (________ Positive growth rate; • Growing populations have a ______ Negative growth rate. shrinking populations have a _______ • Usually expressed in terms of individuals per 1000

Lesson 4. 3 Population Growth Calculating Population Growth

Lesson 4. 3 Population Growth Calculating Population Growth rate 100 -100 49 -180 -100 98 100

Lesson 4. 3 Population Growth How Populations Grow GROWTH • EXPONENTIAL _________ 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

Lesson 4. 3 Population Growth How Populations Grow LOGISTIC GROWTH • ______ Describes how a populations initial exponential growth is slowed and finally stopped by limiting factors • Limiting factors are characteristics of the environment that ____ LIMIT population growth

Lesson 4. 3 Population Growth How Populations Grow • 2 Types of Limiting factors: • Density-dependent: Influence changes with population density. Ex. Food, _____, WATER Space, ______, DISEASE Predation • Density-independent: Influence does ______change with NOT population density. DISASTERS Ex. Natural _______, Climate Change

Lesson 4. 3 Population Growth How Populations Grow • Density Dependent or Density Independent? D Due to severe overcrowding in an Asian village, many _____ children do not survive to reach adulthood. I The eruption of Mt. St. Helens destroys most of the _____ wildlife in the immediate vicinity of the volcano D Due to lack of food and nutrition, large numbers of _____ female mice miscarry their young and fail to reproduce

Lesson 4. 3 Population Growth How Populations Grow • Limiting Factors determine a population’s carrying capacity. • Carrying Capacity – the LARGEST population an _______ environment can sustainably support. • It can change as limiting factors in the environment change

Lesson 4. 3 Population Growth Biotic Potential • Limiting Factors are only part of the story. . We also have to look at the characteristics of the organism • An organism’s ______ MAXIMUM ability to produce offspring in ideal conditions is called _____ BIOTIC ________ POTENTIAL • Two main things influence biotic potential: • 1) GESTATION _______ time – how long it takes for an embryo to develop and “be born” • 2) GENERATION ________ time – the span from an organism’s birth to the time is has its own offspring. HIGH biotic potential can recover more • Organisms with ____________ QUICKLY from population declines than organisms with low biotic potential.

Lesson 4. 3 Population Growth Biotic Potential Scorpion Fish vs. Orangutan Scorpion Fish – Sexually mature at age 3 -5, they lay 50, 000 to 100, 000 eggs a year and they only take 12 to 16 days to hatch Orangutan – Sexually mature at age 10, they give birth to a single baby only once about every 8 years Which organism has the higher biotic potential? Scorpion Fish