Chapter 4:
Section 1:
Population Dynamics
Write the essential questions for this section:
1. What are the characteristics of populations and how they are distributed?
2. What are the differences between density-independent and density-dependent limiting factors?
3. What are the similarities between the different models used to quantify the growth of a population?
Write the Main Idea for this lesson.
RECALL
Recall the definition of the review vocabulary term:
population: the members of a single species
that share the same geographic location at the
same time
population density dispersion density-independent factor density-dependent factor population growth rate emigration immigration carrying capacity
The number of organisms per unit area
Pattern of spacing of a population within an area
Any factor in the environment that does not depend on the number of members
in a population per unit area
Any factor in the environment that depends on the number of members in a
population per unit area
Speed at which population grows
The number of individuals moving away
from a population
The number of individuals moving into a
population
The maximum number of individuals in a species that an environment can
support for the long term
Define the term fluctuate:
Population Characteristics
•Populations are groups of the same species in the same area
Population density:
Spatial distribution:
•Dispersion is the spacing pattern
of a population.
•Can be uniform, clumped groups, or random
Identify each pattern of dispersion as uniform, random, or clumped:
Population ranges:
•A species’ range is its
distribution across the
environment.
•A species might not be able to expand its
population range because it cannot survive the
abiotic conditions found in
Population-Limiting Factors
•Limiting factors are biotic or abiotic forces that keep populations from increasing indefinitely.
•Limiting factors are either density-independent or
Density-independent factors:
•Any factor in the environment that does not depend on the number of members in a population per unit area is a density-independent
factor.
•Usually abiotic, and include:
•Weather events
•Fire
•Human alterations of the landscape
Density-dependent factors:
•Any factor in the environment that depends on the number of members in a population per unit area is a density-dependent
factor.
•Often biotic, and include:
•Predation
•Disease
•Competition
Factor Density-independent Density-dependent
Lava flow
Number of predators
Spread of disease Especially cold winter
Toxic chemical spill into a stream
Another species competing for the same resources
Diverting a river for irrigation
Fungus that attacks elm trees
X
X
X
X
X
X
X
X
Population growth rate:
•The population growth rate (PGR) explains how fast a given population grows.
•Natality: birthrate of a population in a given year
•Emigration: number of individuals moving away from a
population
Exponential growth model:
•Occurs when growth rate is proportional to population size
Logistic growth model:
•Occurs when a population’s growth slows or stops following exponential growth
Carrying capacity:
•Carrying capacity is the maximum number of individuals in a
Reproductive patterns:
•Species vary in the number of births per reproduction cycle, age that reproduction begins, and in the life span.
•Plants and animals are placed into groups based on their reproductive factors.
r-strategy k-strategy
Rate strategy Carrying-capacity strategy
Adapted for fluctuating environment
Adapted to stable environment
Generally small Generally large
Short life span Long life span
Many offspring Few offspring
Expend little energy to raise young
Analyze whether humans are r-strategists or k-strategists. Explain why and support your reasoning:
Humans are k-strategists. Humans produce few offspring compared to other species. Human parents invest energy, resources, and time in caring for their offspring, increasing the chances that the young will survive to reproductive age. Humans
Chapter 5:
Section 1:
Biodiversity
1. What are three types of biodiversity?
2. Why is biodiversity important?
3. What are the direct and indirect values of biodiversity?
Write the Main Idea for this lesson.
RECALL
Recall the definition of the review vocabulary term:
gene: functional unit that controls the
expression of inherited traits
diversity…
means made
of different
The complete disappearance of a species when its last member dies
The variety of species in a particular area
The variety of genes present in a population
The variety of different species in a biological community
The variety of ecosystems present in the biosphere
Write the term next to the correct definition: ecosystem diversity, biodiversity, species diversity, extinction, genetic diversity
species diversity
ecosystem diversity genetic diversity
What is biodiversity?
•Biodiversity is the variety of life in an area that is determined by
the number of different species in that area.
•Biodiversity increases the stability of an ecosystem and contributes to the health of the biosphere.
Genetic diversity:
•Genetic diversity is the variety of genes or inheritable
characteristics that are present in a population.
Species diversity:
Ecosystem diversity:
•The variety of ecosystems that are present in the biosphere is called
ecosystem diversity.
The Importance of Biodiversity
Direct economic value:
•Humans depend on plants and animals for food, clothing, energy, and medicine.
•Most of the world’s food crops come from just a few species.
•Wild species serve as reservoirs of desirable genetic traits that might be needed to improve commercial crop species.
Indirect economic value :
•A healthy biosphere provides many services to humans:
•Green plants provide oxygen and remove carbon dioxide.
•Natural processes provide drinking water that is safe for human use.
Products of
animals Products of plants
Eating meat Eating a salad, wearing cotton Breathing oxygen Wearing wool clothing
Aesthetic and scientific values:
•There is value in maintaining healthy ecosystems that are beautiful or interesting to study
Mass extinction:
•Some scientists believe we are in a period of mass extinction today.
•Some scientists predict that as many as two-thirds of all plant and animal species will become extinct during the second half of this century.
•The current high rate of extinction is a result of the activities of one single species-Homo sapiens
•Humans are changing conditions on Earth faster than new traits can evolve in species to cope with the new conditions.
•Evolving species may not have the natural resources they need.
•Natural resources are the materials and organisms found in the
biosphere, including minerals, fossil fuels, nuclear fuels, plants, animals, soil, clean water, clean air, and solar energy
Renewable resources:
•Resources that are replaced by natural processes faster than they are consumed are called renewable resources.
Nonrenewable resources:
•Resources that are found on Earth in limited amounts or those that are replaced by natural processes over extremely long
periods of time are called nonrenewable resources.
Renewable vs nonrenewable resources:
Renewable Nonrenewable
Both
Compare and contrast renewable and nonrenewable
resources by writing characteristics of each in the Venn diagram:
•Present in limited amounts
•Are replaced over long periods of time
•Replaced by
Sustainable use:
•Using resources at a rate at which they can be replaced or
recycled while preserving the long term environmental health of
