Chapter 19+ 20 Flashcards by diana Diaz

Population

All the individuals of the same species living in the same area

Ex: squirrels on campus

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Difference between population density and species richness ?

Density is number of individuals per unit area

Richness is the number of species living in a particular area

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Random distribution

Individuals show no apparent pattern in their distribution

Ex: dandelions

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Clumped distribution

Individuals are patchy or in groups

Ex: school of fish

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Uniform distribution

Individuals are evenly distributed throughout an area

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Exponential growth

As the population gets bigger, growth rate increases

Rapid growth in populations where resources are unlimited

J-shaped graph

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Logistic growth

Once resources become limited, population growth slows down

Population size reaches carrying capacity

S-shape graph

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Identify as density-dependent tacit or a density-independent factor

a) drought
b) disease
c) Forest fire
d) food

A) density independent
B) density dependent
C) density indecent
D) density dependent

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Intraspecific competition

Competition between members of same species

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Inter specific competition

Competition between members of different species

Can result in competitive exclusion

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Ecological niche

An organism’s role in the community

Its relationship with everything (living and non living )

Every species in an ecosystem has one

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Predation

When one animal hunts and eats another animal (prey)

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Herbivory

Eats producers (plants)

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Foundation species

Important for the structure of the community

Modify the environment and make it habitable

Often abundant

Often producers (photosynthetic)

Ex: trees, coral reefs

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Keystone species

A species that helps to stabilize and maintain other species in an ecosystem

Ex: wolf, sea otter

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Producer

Autotroph

Produce their own food

Carry out photosynthesis

Primary consumer (herbivore)

Eats producers

Secondary consumer (omnivore or carnivore)

Omnivore: eats animals and producers

Tertiary consumer (top carnivores)

Eats animals

What direction to the arrows point in a food web: towards the source of the energy or towards the consumer ?

Towards the consumer

Ecology

Study of interactions between organisms and their environment

Population distribution

The distribution of individuals within a habitat st a given point in time

Human population growth rate in early human history ? During the last 200 years? 20 years ?

Rate was low

200 years: rate was 0.1% per year

Current growth rate: 1.1% per year

What are the environmental impacts of human population growth?

We need more:

Food( and land for agricultural and grazing)
Water 
Energy
Raw materials 
Space

Carrying capacity

The maximum number of individuals that can be supported indefinitely in a given environment

Density - dependent factors

Factors that increase effects as population size and density increases Limits population growth by: Limited food supply Increased risk of diseases Increases in waste levels Cause: Decrease in birth rates and increases death rates

Density- independent factors

Population limiting factors that occur regardless of population size Ex: natural disasters, pollution, droughts

Consumption ?

resources being use Waste produced ( pollution )

Scenarios if population surpasses the carrying capacity ?

Population crash Population cycle : repeated crashes and rebounds

Age structure diagrams

A summary of the numbers of individuals in different age groups Can be used to predict a populations future growth

Age diagrams (pyramid with large base)?

The majority of the population is young and that the population is still growing

Age diagram (narrow base)

Decrease in population growth Developed counties with greater % of middle aged and older individuals

Age diagram (column)

Slow growth Fewer young and reproductive aged individuals and a greater proportion of older individuals

Female literacy occurs more in bigger populations True or false

True

More income per capita (country) means a bigger population True or false

True