Transcript An Introduction to Ecology

An Introduction to
Ecology
The Distribution and Adaptations
of Organisms
Introduction to Ecology
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Ecology is the study of organisms and their
interactions with their environment.
The environment includes 2 types of factors:
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Biotic factors – the living parts of the environment
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Plants, animals, bacteria, fungi, protists
Abiotic factors – the nonliving parts of the environment
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Water, oxygen, light, temperature, etc.
Abiotic or Biotic?
Abiotic or Biotic?
Abiotic or Biotic?
Abiotic or Biotic?
Levels of Organization
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Ecologists can look at the world in levels of increasing complexity:
 Population –
 A group of organisms of the same species that live together in
a certain area
 Example: a pride of lions in the Serengeti
 Community –
 A group of organisms of different species that live together in
a certain area
 Example: all of the organisms living in or around a lake
 Ecosystem –
 All the living and nonliving things in a certain area
 Example: Lake, trail in Red Rock Canyon
 Biome – a group of ecosystems that have similar climates and
communities
 Example: Tundra, Desert, Deciduous Forest
 Biosphere – the entire portion of the planet that supports life
Distribution of Species
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When considering ecology, the distribution of
species are determinant in how an
ecosystem evolves
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Dispersal is the movement of individuals away
from centers of high population density or from an
area of origin
Biological imperative is to breed and pass on
genetic information (thus they should spread)
Strategies for Dispersal
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Many species are not able to migrate to all
parts of the world (geographic barriers)
Some organisms can overcome these
barriers and allow species to spread
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One method is known as natural range
expansion (the organism is able to overcome
barriers and begin colonies in different locations)
Example: many species of strong flying birds
(egret, grackle) have expanded into Africa,
Eurasia, Australia and recently (last 150 years)
both of the Americas
Strategies for Dispersal
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Another method to move species to new
areas is Species Transplants
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Humans love to influence their natural
surroundings
We have brought many foreign species into new
habitats
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Example: Mammals are slowly “taking over” many of
the niches in Australia
The Eucalyptus tree in Australia has several footholds
in California
Success of Dispersion: Biotic Factors
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Even though an organism is able to spread to
a new environment, it does not mean that it
will be successful
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Behavior of the organism may not be suitable to
the environment (mating rituals, reproductive
barriers, etc)
Negative interactions with other organisms
(parasites, predation, disease, competition for
resources)
The Importance of Abiotic Factors
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Not every organism can live everywhere on Earth
Abiotic factors determine which organisms can
survive where:
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Temperature – effect on body temperature
Water – too much/not enough water
Light – availability for photosynthetic organisms
Wind – amplifies effects of temperature
Rocks/Soil – which organisms can live with/on them, based
on pH and mineral composition
Periodic Disturbances – catastrophes, such as tornadoes,
fires, tsunamis, etc.
Climate: Abiotic Factor
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Climate combines four abiotic factors
(temperature, water, sunlight, and wind)to
determine prevailing weather conditions that
greatly affect ecosystems
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Macroclimate: patterns on a global, regional or
local level
Microclimate: very fine patterns that are
localized to very specific regions in an ecosystem
(example: communities underneath a log)
Determination of Climate
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Many factors affect a global or regional
climate
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Solar energy
Planet’s movement in space
Sun’s warming effect on the atmosphere
Land
Water
Cycles of air movement
Evaporation/Precipitation
Oceans/Bodies of water
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Ocean currents have a huge influence on
climate
 Heat or cool air masses (affects
weather)
 In general, large bodies of water (lakes
included) moderate temperatures
 Remember properties of water
Mountains
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Mountains affect both amount of sunlight and
rainfall
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Depending on which side of a mountain an
ecosystem is on, they may receive more sunlight
or less sunlight (if in the shade)
Additionally, mountains force clouds to release
their moisture before crossing over the peak
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One side of a mountain often receives significantly
more precipitation than the other
Elevation can cause different climates due to
temperature, O2 content and precipitation
Seasonality
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The Earth’s relative position around the sun
determines the seasons
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Facing away from sun (fall and winter)
Facing towards the sun (spring and summer)
The different levels of solar radiation lead to
variations in wind patterns, temperatures,
variations in ocean currents
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All of these variations change the climate in a region
that an organism must adapt to
Microclimates
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As varied as macroclimates can be,
microclimates have infinite variations
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Shading from biotic or abiotic structures affect sun
exposure
Clearing vs. forested can have effects on
temperature and wind exposure
High ground vs. low ground for water availability
Above vs. below ground
Again organisms must adapt to survive in
each scenario
Long-term Climate Change
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Even with the variety of change in climates,
global climates (as a whole) are fairly
predictable based on environmental data and
historical analysis (otherwise, weathermen
wouldn’t have a job)
Yet even large-scale climates can be altered
over time
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Ice ages (last for about 40,000 – 100,000 years)
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Next ice age is predicted in the next 10,000 years
Global warming
Long-term Climate Change
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Many of these changes will have far-reaching
effects on ecosystems and species
distribution
Many of the extinctions that have taken place
on Earth are due to an organisms inability to
adapt to a changing environment
Homeostasis
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Organisms must maintain homeostasis, a steadystate internal environment, despite changes in the
external environment
Organisms respond to abiotic factors in one of two
ways (REVIEW):
1. Regulators (endotherms) maintain a nearly
constant internal environment, despite external
conditions (Warm-blooded)
2. Conformers (ectotherms) allow their internal
environment to vary (Cold-blooded)
- live in environments which remain relatively
stable
The Principle of Allocation
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This principle states:
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Each organism has a limited amount of energy
that can be spent on obtaining food, escaping
from predators, coping with environmental
fluctuations (maintaining homeostasis), growth,
and reproduction
Adapting to Changing Conditions
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Organisms can respond to their changing
environments using 3 different types of responses:
1. Physiological Responses
- changing the functioning of the body
- acclimation
- athletes in Torino, moving to Denver...
2. Morphological Responses
- changing the anatomy (structure) of the body
- example: dogs growing thicker fur
Adapting to Changing Conditions
3. Behavioral Responses
- changing behavior to adapt to the change
- moving to a more favorable location
- cooperative behavior (huddling, etc.)
Overview of Biomes
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Not on AP test, but will be on MY test (good
background information)
Aquatic
Terrestrial (Our focus will be on these!)
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Tundra
Taiga
Tropical Forest
Savanna
Chaparral
Desert
Temperate Grassland
Temperate Deciduous Forest
Tundra
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Arctic = 20-60 cm/yr.
Alpine (mountains) = may exceed 100 cm
Average winter temp. -30 degrees C
Summer < 10 degrees C
Long winter; short summer
Herbaceous (low) plants, a few DWARF shrubs due
to PERMAFROST.
Musk oxen, caribou, reindeer, bears, wolves,
various birds
High latitudes or highest elevations (even at
equator!)
Taiga (Northern Coniferous
Forest)
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30-70 cm ; some much more
Winters -50 degrees C in winter
Summer 20 degrees C
Long winter; short summer may be hot
Plants: cone-bearing trees, diverse
shrubs,herbs
Animals: Birds, moose, bears, Siberian tigers;
insects
Northern N. Am. and Eurasia to edge of
tundra
Tropical Forest
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T. Rainforest: 200-400 cm/yr
T. Dry forest 150 – 200 cm/yr
25-29 degrees year round (Warm!)
Summer year round
Plants: diverse; 4 or more layers
Animals: diverse: 5-30 million species yet to
be discovered!
Equatorial regions
Savanna
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Seasonal rainfall; 30-50 cm/yr with long drought
season
Temperature: 24-29 degrees C (warm!); more
variation that Tropical forests
Dry season lasts 8-9 months
Plants: Scattered trees; thorny; small leaves
(why?)Grasses; Must be fire & drought tolerant
Animals: Herbivorous mammals; insects; grazers
Equatorial & subequatorial regions
Chaparral
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Seasonal ppt.; Rainy winter; Long dry summer (3050 cm)
Cool fall, winter, & spring (10-12 degrees C)
Summer can reach 30-40 degrees C
Plants: shrubs, small trees, grasses; adapted to
drought; some have seeds that germinate after fire.
Animals: mammals (browsers) amphibians, reptiles,
insects
Mid latitude coasts
Desert
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< 30 cm / yr (arid/dry)
Hot deserts > 50 degrees C
Cold deserts (Antarctica) <-30 degrees C
Temps vary seasonally and daily (colder at
night)
Plants: Cacti, shrubs w/ deep roots (why?);
small leaf surface area (why?)
Animals: lizards, scorpions; birds; insects;
many nocturnal animals (why?)
Temperate Grassland
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Dry winters; wet summers;; 30-100 cm/yr.;
seasonal drought
Cold winters < -10 degrees C; Hot summers
30 degrees C
Plants: Grasses
Animals: Large grazers; burrowing mammals
Plains & prairies around the world
Temperate Deciduous Forest
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70-100 cm/yr
Cold Winters 0 degrees; Hot summers 35
degrees C; 4 distinct seasons
Plants: Trees, shrubs, herbaceous layer;
(broadleaved, deciduous plants)
Animals: variety of mammals, birds, insects
Midlatitudes
Our biome!