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Labs, Activities, and WS for this presentation:
Lorax WS
ECOLOGY (EOG L17)
Living organisms form relationships with their environments.
ECOLOGY = the study of organisms
and how they interact with their
environments.
treklens.com
CrashCourse Ecology Intro https://www.youtube.com/watch?v=izRvPaAWgyw
Species = individuals that can interbreed and produce
fertile offspring
Canus latrans
Lycaon pictus
Vulpes vulpes
How many species do you see?
Canus lupus
Population = group of individuals of
the same species living in the same area
Community = group of populations
living in the same area
Ecosystem = group of communities
living in the same area
Four Factors Affecting Populations
Factors that Limit Populations
Abiotic = non-living
Biotic = living
11 (rain)
1
2
7
6
5
10
9
8
4
3 (soil)
12 (bacteria)
Limiting Factors
= anything
that where
limits the
of a givenlives
population
Habitat
= the place
ansize
organism
Niche = the role an organisms plays within its ecosystem
Density-Dependent Factors = limits to growth of a
population based on the density (numbers of individuals in a
given area) of the population.
• Individuals compete for resources
Amount of resources available limit the population.
• Predator-Prey Ratios
The ratio of predators to prey may limit the population.
Energy in Ecosystems
(EOG L18 (with Focus on Inquiry) & ACT L39)
The Players:
• Sun (main energy source)
• Producers/Autotrophs (plants)
• Consumers/Heterotrophs (eaters)
Herbivores (plant eaters)
Carnivores (meat eaters)
Omnivores (plant & meat eaters)
• Scavengers (leftover eaters)
• Decomposers (breakdown crew)
Who’s Who?
Food Chains
Go in ONE direction.
Food Web = a network of interrelated food chains.
Some webs
include both
aquatic and
terrestrial
organisms.
Cause &
Effect: What
happens if
one element
of the web is
removed?
Energy Pyramids = shows energy consumption.
Biomass Pyramid = shows amount of mass at each level.
Each step is called a Trophic Level.
Lose one “10th” with each step up the pyramid.
Only 10% of
energy is
passed to
the next
level.
Succession = plant changes in an ecosystem
Primary Succession – from original dirt to hardwoods
Secondary Succession – rebuilt from cut down forest
Cycling of Matter in Ecosystems
OXYGEN (at Lake Lure, NC)
CO2 remains in air as pollution
Oxygen released into air by plants
CO2
Oxygen released into air by industry as CO2
O2
CO2 removed from air by plants
CO2
Oxygen released into air as CO2
Oxygen removed from air by animals
Cycling of Atmospheric Gases
NITROGEN
(EOG L19)
1. Nitrogen in the air
4. Cow eats nitrates in plants
5. Nitrates leave cow
3. Nitrates absorbed by
plants to make chloroplasts
2. Nitrogen-Fixing
Bacteria
Nitrates
6. Decomposers
Nitrates
N
7. Denitrifying
Bacteria
CrashCourse Phosphorus & Nitrogen Cycles https://www.youtube.com/watch?v=leHy-Y_8nRs
Other Relationships in Ecosystems (EOG L20)
Competition = occurs when different organisms try to get the same
resources.
Cooperation = occurs when different organisms work
together to get the same resources.
SYMBIOSIS = permanent relationship between organisms of two
different species
MUTUALISM = both organisms benefit
EXAMPLE: The ant and the acacia tree. The ants receive shelter,
food and security from the tree. The tree receives nutritional
benefits from the ants.
SYMBIOSIS = permanent interrelationship between organisms of two
different species
COMMENSALISM = one organism benefits and the other is not affected
EXAMPLE: Cattle
and cattle egrets.
As the cows eat the
grass, they stir up
insects for the
egrets to eat.
SYMBIOSIS = permanent relationship between organisms of two
different species
PARASITISM = one organism benefits and the other is harmed
Parasite = benefits
Host = harmed
EXAMPLE: Tick on a
dog. Tick gains food
and harms dog by
drinking blood.
Predator
Prey
Number of Individuals
• Predator-Prey Relationships
The ratio of predators to prey may limit the population.
Density-Dependent = density affects population growth
60
50
40
Predator
gets disease.
Prey
overpopulates.
Prey starves.
Prey goes up predators go up.
Prey goes down predators go down.
30
20
Direct Relationship
10
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
YEAR
• Natural Disasters and populations
Density-Independent = density of population has no
effect on population growth
Population Dynamics (ACT L40)
Migration = movement from one area to another
Immigration = movement into an area
Emmigration = movement out of an area
Immigration of African Killer Bees
Carrying Capacity = the amount of organisms an ecosystem can
support.
Exponential Growth
Population growth of rabbits:
> Start with one breeding pair (male and female)
> The pair produces a new breeding pair every 12 weeks.
> Not including deaths.
Goes from 2 rabbits
(original pair) to
Over 140 rabbits
in 30 weeks!
Just imagine the
population growth
with the normal 4-12
kits per litter!!!!
Exponential Growth
J-Curve
Exponential Growth = rapid growth of a population.
http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html
ANY
QUESTIONS?