Evolution, Biodiversity, and Population Ecology - PowerPoint PPT Presentation


Title: Evolution, Biodiversity, and Population Ecology


1
Lecture 4
  • Evolution, Biodiversity, and Population Ecology

2
What will I learn today?
  1. What is evolution
  2. Discuss your feeling about evolution
  3. Learn examples of biodiversity
  4. Learn basics of ecology necessary to understand
    environmental biology

3
Costa Rican Cloud Forest
  • Case study
  • There one year and gone the next!

4
Monteverde cloud forest
5
Golden toads of Costa Rica
6
What happened?
  • Science wants to know the truth based on sound
    principles
  • Were the frogs hunted to death?
  • Were the frogs eaten by predators?
  • Were the frogs killed by a disease?
  • Did they leave the region?
  • Did they become something else?
  • Were they caught and sold to the pet trade?
  • ???? What else ????

7
Scientific Analysis
By looking over the data conclusions could be
drawn.
8
Environment kills!
  • In late 1960s lots of these frogs
  • The forests were moist and had lots of cloud
    cover
  • In late 1990s all the frogs were extinct!
  • The forests were drier and there was little cloud
    cover
  • Something has caused a change in the climate

9
1960s 1990s
10
Global Warning
  • The death of the frogs has been linked to the
    warming of the oceans and the resulting
    deflection of the clouds, reducing the amount of
    moisture. Frogs needs moisture to live.
  • Actually, the real answer now is that the
    increased temperatures at night and lower
    temperatures in the day promote a fungus to grow
    and kill the frogs!
  • This is our first example of GLOBAL WARMING
    killing species - remember!

11
Evolution
  • Introduction to evolution
  • Evolution by natural selection is one of the
    best-supported and most illuminating concepts in
    all of science, yet it has remained socially
    controversial among some nonscientists who fear
    it threatens their religious beliefs.

12
What is evolution?
  • In the strict sense it is
  • Change over time
  • Rivers change direction over time
  • Mountains form and erode over time
  • Biological evolution is
  • Change in the genetic information over
    generations
  • We will understand this over the course of the
    course

13
Evolution is our best supported scientific theory
  • LAYMAN - a theory is a hunch, a guess, a shot in
    the dark!
  • SCIENTIST - a theory is something well supported
    by evidence.
  • Watch this great definition of a scientific theory

14
How are there so many life forms on Earth?
  • About 1.5 million plus species known
  • Expect to find up to 100 million
  • All arose due to Evolution
  • How?
  • By process of speciation

15
Many possible ways
One method is by physical isolation
16
DNA damage
  • What causes the DNA to change?
  • Many factors alter DNA
  • Cosmic radiation
  • Copying errors during DNA replication
  • Cellular heat
  • Chemicals in the environment
  • Any changes have to pass to offspring to be
    classified as evolution

17
Natural Selection
  • More babies are born than can be supported by the
    environment
  • Each baby is slightly different from the others
    in the population
  • Some are better suited to that environment over
    others
  • These survive and the others do not
  • This video provides a great explanation

18
Examples of Evolution
  • Selective breeding by humans
  • Dogs from wolf
  • Crops from weeds

19
Microbes real-time evolution
  • The time it takes for large creatures to evolve
    is very long.
  • However, since the discovery of microbes we can
    see evolution in action
  • The video, about TB, provides and excellent
    example

20
Massive death
  • The Earth has seen 5 mass extinction in the past
  • Each killed off between 50 to 95 of species
    alive at the time
  • Permian period 250 million years ago
  • Global warming
  • K-T event 5 million years ago
  • Killed the dinosaurs and was caused by a meteor
    impact

21
Round 6 has started
  • Today we are seeing another round
  • Caused by humans
  • Population growth issues
  • Development
  • Resource depletion
  • Relocations
  • Species loss is forever!

22
God and Evolution
  • Naturally, science is now trying to understand
    where we came from, who we are, and why?
  • These questions and the answers impinge on other
    human values
  • This video presents an opinion on this topic

23
Biodiversity
24
Biodiversity
  • Biodiversity - refers to the sum total of all
    organisms in an area.
  • Species - is a particular type of organism that
    can freely breed and produce fertile offspring.
  • Population - is a group of individuals of a
    particular species that live in the same area.

25
Ecology
  • Habitat - specific environment in which an
    organism lives
  • Both living and non-living parts
  • Niche - a habitat supplying the factors necessary
    for the existence of an organism or species
  • No two species can share the same exact niche -
    one will go extinct!

26
Populations follow rules
  • Understanding these is important in predicting
    the future.
  • Age structure diagrams (age pyramids) can tell us
    how that population will develop in the future

27
The shape of the graph is very important
28
Population demographics
  • Another key measure is growth rate
  • The rate of growth of a population is measured
    using this formula
  • (Crude birth rate immigration rate) - (Crude
    death rate emigration rate) Growth rate
  • Thus, a growth rate of 6/1,000 would be expressed
    as 6/1,000 100 0.6

29
Exponential Growth
  • A population that increases by a fixed percentage
    each year is said to exhibit exponential growth

This form of growth cannot be sustained for long.
Something (food, shelter, space, waste) will
change it.
30
Carrying capacity
  • Every population eventually is constrained by
    limiting factors, physical, chemical, and
    biological characteristics of the environment
    that restrain population growth.
  • The interaction of these factors determines the
    carrying capacity
  • the maximum population size of a species that a
    given environment can sustain.

31
Carrying Capacity
32
  • As we have seen, the global human population has
    risen from fewer than 1 billion 200 years ago to
    6.7 billion today, and we have far exceeded our
    historic carrying capacity.
  • What accounts for the increase in Earths
    carrying capacity for us?
  • Do you think there are limiting factors for the
    human population?
  • What might they be?
  • Do you think we can keep raising our carrying
    capacity in the future?
  • Might Earths carrying capacity for us decrease?

33
Conclusions
  1. You may appreciate evolution theory a bit more.
  2. The evolutionary processes of natural selection,
    speciation, and extinction help determine Earths
    biodiversity.
  3. Understanding how ecological processes work at
    the population level is crucial to protecting
    biodiversity threatened by the mass extinction
    event that many biologists maintain is already
    underway.
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Evolution, Biodiversity, and Population Ecology

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Transcript and Presenter's Notes

Title: Evolution, Biodiversity, and Population Ecology


1
Lecture 4
  • Evolution, Biodiversity, and Population Ecology

2
What will I learn today?
  1. What is evolution
  2. Discuss your feeling about evolution
  3. Learn examples of biodiversity
  4. Learn basics of ecology necessary to understand
    environmental biology

3
Costa Rican Cloud Forest
  • Case study
  • There one year and gone the next!

4
Monteverde cloud forest
5
Golden toads of Costa Rica
6
What happened?
  • Science wants to know the truth based on sound
    principles
  • Were the frogs hunted to death?
  • Were the frogs eaten by predators?
  • Were the frogs killed by a disease?
  • Did they leave the region?
  • Did they become something else?
  • Were they caught and sold to the pet trade?
  • ???? What else ????

7
Scientific Analysis
By looking over the data conclusions could be
drawn.
8
Environment kills!
  • In late 1960s lots of these frogs
  • The forests were moist and had lots of cloud
    cover
  • In late 1990s all the frogs were extinct!
  • The forests were drier and there was little cloud
    cover
  • Something has caused a change in the climate

9
1960s 1990s
10
Global Warning
  • The death of the frogs has been linked to the
    warming of the oceans and the resulting
    deflection of the clouds, reducing the amount of
    moisture. Frogs needs moisture to live.
  • Actually, the real answer now is that the
    increased temperatures at night and lower
    temperatures in the day promote a fungus to grow
    and kill the frogs!
  • This is our first example of GLOBAL WARMING
    killing species - remember!

11
Evolution
  • Introduction to evolution
  • Evolution by natural selection is one of the
    best-supported and most illuminating concepts in
    all of science, yet it has remained socially
    controversial among some nonscientists who fear
    it threatens their religious beliefs.

12
What is evolution?
  • In the strict sense it is
  • Change over time
  • Rivers change direction over time
  • Mountains form and erode over time
  • Biological evolution is
  • Change in the genetic information over
    generations
  • We will understand this over the course of the
    course

13
Evolution is our best supported scientific theory
  • LAYMAN - a theory is a hunch, a guess, a shot in
    the dark!
  • SCIENTIST - a theory is something well supported
    by evidence.
  • Watch this great definition of a scientific theory

14
How are there so many life forms on Earth?
  • About 1.5 million plus species known
  • Expect to find up to 100 million
  • All arose due to Evolution
  • How?
  • By process of speciation

15
Many possible ways
One method is by physical isolation
16
DNA damage
  • What causes the DNA to change?
  • Many factors alter DNA
  • Cosmic radiation
  • Copying errors during DNA replication
  • Cellular heat
  • Chemicals in the environment
  • Any changes have to pass to offspring to be
    classified as evolution

17
Natural Selection
  • More babies are born than can be supported by the
    environment
  • Each baby is slightly different from the others
    in the population
  • Some are better suited to that environment over
    others
  • These survive and the others do not
  • This video provides a great explanation

18
Examples of Evolution
  • Selective breeding by humans
  • Dogs from wolf
  • Crops from weeds

19
Microbes real-time evolution
  • The time it takes for large creatures to evolve
    is very long.
  • However, since the discovery of microbes we can
    see evolution in action
  • The video, about TB, provides and excellent
    example

20
Massive death
  • The Earth has seen 5 mass extinction in the past
  • Each killed off between 50 to 95 of species
    alive at the time
  • Permian period 250 million years ago
  • Global warming
  • K-T event 5 million years ago
  • Killed the dinosaurs and was caused by a meteor
    impact

21
Round 6 has started
  • Today we are seeing another round
  • Caused by humans
  • Population growth issues
  • Development
  • Resource depletion
  • Relocations
  • Species loss is forever!

22
God and Evolution
  • Naturally, science is now trying to understand
    where we came from, who we are, and why?
  • These questions and the answers impinge on other
    human values
  • This video presents an opinion on this topic

23
Biodiversity
24
Biodiversity
  • Biodiversity - refers to the sum total of all
    organisms in an area.
  • Species - is a particular type of organism that
    can freely breed and produce fertile offspring.
  • Population - is a group of individuals of a
    particular species that live in the same area.

25
Ecology
  • Habitat - specific environment in which an
    organism lives
  • Both living and non-living parts
  • Niche - a habitat supplying the factors necessary
    for the existence of an organism or species
  • No two species can share the same exact niche -
    one will go extinct!

26
Populations follow rules
  • Understanding these is important in predicting
    the future.
  • Age structure diagrams (age pyramids) can tell us
    how that population will develop in the future

27
The shape of the graph is very important
28
Population demographics
  • Another key measure is growth rate
  • The rate of growth of a population is measured
    using this formula
  • (Crude birth rate immigration rate) - (Crude
    death rate emigration rate) Growth rate
  • Thus, a growth rate of 6/1,000 would be expressed
    as 6/1,000 100 0.6

29
Exponential Growth
  • A population that increases by a fixed percentage
    each year is said to exhibit exponential growth

This form of growth cannot be sustained for long.
Something (food, shelter, space, waste) will
change it.
30
Carrying capacity
  • Every population eventually is constrained by
    limiting factors, physical, chemical, and
    biological characteristics of the environment
    that restrain population growth.
  • The interaction of these factors determines the
    carrying capacity
  • the maximum population size of a species that a
    given environment can sustain.

31
Carrying Capacity
32
  • As we have seen, the global human population has
    risen from fewer than 1 billion 200 years ago to
    6.7 billion today, and we have far exceeded our
    historic carrying capacity.
  • What accounts for the increase in Earths
    carrying capacity for us?
  • Do you think there are limiting factors for the
    human population?
  • What might they be?
  • Do you think we can keep raising our carrying
    capacity in the future?
  • Might Earths carrying capacity for us decrease?

33
Conclusions
  1. You may appreciate evolution theory a bit more.
  2. The evolutionary processes of natural selection,
    speciation, and extinction help determine Earths
    biodiversity.
  3. Understanding how ecological processes work at
    the population level is crucial to protecting
    biodiversity threatened by the mass extinction
    event that many biologists maintain is already
    underway.
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