11/11 and 11/12 11/12 ATB  Review: What is a population? Today: Go over the tests --- questions? Start new chapter on populations and population growth

Chapter 5 - Populations

5.1 How Populations Grow

How We Describe Populations Four ways to describe a population: Geographic Range Density and Distribution Growth Rate Age Structure

Describing Populations How do you describe an organisms geographic range? Where it lives (area inhabited by the organism) Density and Distribution Population density – number of individuals per unit area Distribution – How organisms are spaced out

Population Distribution

Population Distribution

Population Age Structure Shows the number of individuals of each age Why is this important for describing populations? Allows us to predict what the population will do in the future.

11/13 and 11/14 11/14 ATB  What will the population probably do in the future? (increase, decrease, remain stable) Today: Continue describing populations Start carrying capacity assignment

Scientists use age structure pyramids to predict future growth. What will populations do in the future?

Population Growth What can cause a population to increase or decrease? Birthrates Death Rates Immigration Emigration

Types of Growth What are the two typical types of growth curves? Exponential Logistic

Exponential Growth Exponential Growth – Draw the curve for exp. growth Growth seen typically under ideal conditions with unlimited resources Seen by a “J” shaped curve Does it occur in nature? For short periods of time, but inevitably it must slow down. Why? Resources become limited Draw the curve for exp. growth

Exp. Growth in rapid vs. slow Reproduction

What type of curve does the human population show?

Logistic Growth Logistic Growth Population growth that slows and then stops due to limiting factors “S” shaped curve

Logistic Growth and Carrying Capacity the number of individuals of a species an ecosystem can support The flat place on the graph where the population levels off is called the carrying capacity of the population.

5.2 Limits to Growth

Book Assignment Page 135 #1-4

What controls the carrying capacity? The carrying capacity is controlled by the ecosystems limiting factors. Limiting Factors – factors that keep organism population numbers from growing out of control

Limiting Factors List five factors that could limiting the population of deer in the Pennsylvania. Competition Predation Parasitism / Disease Weather events Natural Disaster

List four factors that keep a turkey population from getting too high. Weather Conditions Extreme Weather Natural Disasters Habitat Quality Competition Species Survival Predation Parasitism and Disease Reproduction

11/5 and 11/18 11/18 ATB  What controls the carrying capacity? Today: Quick review Carrying capacity assignment

Review Questions What are the two types of growth curves we discussed? Describe the two growth curves. What is population density? What is population distribution? What 4 factors affect a populations size? What is carrying capacity? What are limiting factors?

11/19 and 11/20 11/20 ATB  List any three limiting factors. Today: Carrying capacity assignment  due Thursday Describe density dependent / independent factors

Carrying Capacity Questions #2 and #3 on the assignment… Any other questions? Assignment due Thursday

Review Quiz What could occur to this population in the future? A. Rapid growth B. Slow growth C. Decreasing growth D. Steady growth What type of growth is very rapid? A. logistic B. exponential C. limiting factors The number of organisms the ecosystem can support. A. limiting factor B. carrying capacity C. exponential growth D. habitat T / F: Emigration is when individuals leave a population.

Assignment Page 135 #1-4 This will NOT be collected today. We will add another assignment to the page and THEN it will be collected.

11/21 and 11/22 11/21 ATB  What controls the carrying capacity of a habitat? Today: Turn in your carrying capacity graphs Describe density dependent / independent factors

Density-Dependent Limiting Factors Limiting factors that begin affecting a population which has reached a certain size Population gets large = density-dependent limiting factors start affecting the population What is going to happen to intraspecific competition as the population grows. Give an example It will increase More individuals begin competing for increasingly scarce resources like food and shelter.

Density-Dependent Limiting Factors Predation and Herbivory Describe how predation and herbivory act as a density-dependent limiting factor As the population of predators go up the population of prey will decrease. This causes the predators to then decrease. Same thing happens with herbivores and if too large a population is present the plant population will be affected

Density-Dependent Limiting Factors Parasitism and Disease In large populations parasites and disease are able to spread more rapidly Stress From Overcrowding. Too much competition / fighting can cause stress individuals, which can lead to weakened ability to fight diseases

c A B Review: Where is the carrying capacity reached? Where is the growth the fastest? Where is the growth slowing down? What controls the carrying capacity? A B c

Density-Independent Limiting Factors Factors that affect the population regardless of the population size Can cause a population crash Examples: Unusual weather Drought / floods Fires

Density Dependent vs. Density Independent Label the the following as “density dependent” or “density independent” A fire kills off a number of the population. Predators start congregating around the prey population. A disease runs rampant through the population. A cold winter causes starvation of a number of the species Organism become weakened b/c of stress from overcrowding and competition

5.2 Assessment Page 141 #1-3

Quick Talk Carnivore Carrying capacity Carrying capacity Limiting factors Exponential growth Producer Carrying capacity Exponential growth Decomposer Limiting factors Omnivore

5.3 Human Population Growth

Human population growth Review: What type of growth curve does the human population have? Exponential Thomas Malthus predicted in the early 1800’s that the human population would crash b/c of famine and disease Famine and disease are examples of density _____dependant______ factors. Why didn’t Malthus’ predictions come true? technology

Human Growth

What is our approx. pop? Human Population Clock What problems are we causing with our high population numbers? Pollution Damage to ecosystems Causing extinctions of species

HE WHO ONCE DOMINATED THE EARTH – IN MEMORY OF MAN 2,000,000 BC – AD 2030 HE WHO ONCE DOMINATED THE EARTH – DESTROYED IT WITH HIS WASTES HIS POISONS AND HIS OWN NUMBERS

Most populated Countries 1.35 billion = China 1.23 billion = India 313 billion = US

Where is human pop. growth the highest? Why??

Demographic Transition Shows the predicted change in birth rates / death rates as a country industrializes PREDICT the birth rate and death rates for the following countries (low or high) Affluent country with health care: BR = ____ DR = ____ Very poor country: BR = _____ DR = _____ Poor nation with some access to medicines: BR=____ DR=______

Demographic Transition Stage 1 = high birth rates and high death rates Stage 2 = high birth rates but death rates fall Stage 3 = low birth rates and low death rates

Why are birthrates high during Stage 1 and 2? Lack of birth control Many babies do not survive Why do death rates decrease as a population industrializes? Better medicine Better sanitation Why do birth rates fall during stage 3 of demographic transition? Access to birth control Women want education or career

Demographic Transition

Age structure and Population Growth Age Structure Diagrams Help predict future population growth trends

The End

5.3 Assessment Pg 145 #1-2

POPULATION SIZE * 1,000 Y E A R (1900) 75 70 65 60 55 50 45 40 POPULATION SIZE * 1,000 35 30 carrying capacity 25 20 15 10 5 04 06 08 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 Y E A R (1900)

Climate Change – General Info The majority of greenhouse gasses have been emitted since the beginning of – the industrial revolution The burning of fossil fuels (and biomass) releases carbon that has been trapped for millions of years This carbon is released in the form of CO2 The three main fossil fuels are coal, oil and natural gas Slash and burn farming reduces the ability of Earth’s forests to soak up the CO2. This also releases the carbon that was trapped in the trees, into the atmosphere in the form of carbon dioxide

Population size and CO2 Industrializing nations a problem? What is the main issue with industrializing nations that have very large populations? They are burning fossil fuels at an enormous rate (more people = more pollution) Industrializing nations with large populations? China pop = 1.3 billion India pop = 1.1 billion US pop = 300 million

Evidence of Global Warming…?

CO2 and Temp What we see is a positive correlation between the temp. and the levels of CO2 in the atmosphere. This means the more carbon dioxide there is, the higher the temp. will be CO2 levels are now at the highest level in 150,000 years (actually 650,000 years)

Reading the graphs…

Average Temp Increase - (Since 1855) Current Temperature Increase: Overall temp. on earth (near the surface) has increased 1.33 degree Fahrenheit (± 0.32 F) in the 20th century. Models predict that the temp. will rise a further 2.0 to 11.5 °F in the 21st century. Hottest Years in 150 The hottest years recorded, EVER since recording began in 1880 were within the last 10 years