Transcript 13.1 Ecologists Study Relationships

13.1 Ecologists Study Relationships
13.1 Ecologists Study Relationships
Ecology - study of the interactions between living things
and their surroundings.
13.1 Ecologists Study Relationships
Levels of Organization
• Biosphere
• Ecosystem
• Community
• Population
• Organism
13.1 Ecologists Study Relationships
Biosphere
• The portion of
earth that supports
life
• Extends from the
lower atmosphere
to the bottom of
oceans
• Supports diverse
array of organisms
and wide range of
climates
13.1 Ecologists Study Relationships
• An ecosystem/biome - all of the living
and nonliving things in a given area
(climate, soil, water, rocks).
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Earth has six major biomes.
13.1 Ecologists Study Relationships
Community
• All the populations of different species that live in
the same place at the same time.
• Example
– Forest community
Flowers, bushes, trees, snakes, frogs, birds, squirrels,
deer, etc…
13.1 Ecologists Study Relationships
Population
• A group of organisms, of one species, which
interbreed and live in the same place at the same
time.
• Example
– Population of bullfrogs in Jackson Bog
13.1 Ecologists Study Relationships
• An organism - individual living thing,
ex: alligator.
Organism
Organism
13.1
Ecologists
13.2 Biotic
and AbioticStudy
FactorsRelationships
KEY CONCEPT
Every ecosystem includes both living and nonliving
factors.
13.1
Ecologists
13.2 Biotic
and AbioticStudy
FactorsRelationships
• Abiotic factors are nonliving things.
– moisture
– temperature
– wind
– sunlight
– Soil
• Not constant (always changing)
sunlight
moisture
13.1
Ecologists
13.2 Biotic
and AbioticStudy
FactorsRelationships
Biotic Factors
• Living components of the environment
13.1
Ecologists
13.2 Biotic
and AbioticStudy
FactorsRelationships
• A keystone species is a species that has an unusually large
effect on its ecosystem.
keystone
16.3
13.2
Biotic
Quality
and AbioticStudy
FactorsRelationships
13.1Water
Ecologists
• Indicator species provide a sign of an ecosystem’s health.
– amphibians
– top predators
13.1
Ecologists
Study Relationships
13.3 Energy
in Ecosystems
Producers provide energy for other organisms in an
ecosystem.
• autotrophs - make their own food.
13.1
Ecologists
Study Relationships
13.3 Energy
in Ecosystems
Almost all producers obtain energy from sunlight.
• Photosynthesis
• Chemosynthesis – produce energy from chemicals
carbon dioxide + water +
hydrogen sulfide + oxygen
sugar + sulfuric acid
13.1
Ecologists
Study Relationships
13.3 Energy
in Ecosystems
Measuring productivity
• Gross primary productivity – rate at which
producers capture E
• Biomass – organic material in an ecosystem
– Only E stored as biomass is available to other
organisms in the ecosystem
13.1
Ecologists
Study Relationships
13.3 Energy
in Ecosystems
Consumers are organisms that get their energy by eating
other living or once-living resources.
• heterotrophs
13.1
Ecologists
Study Relationships
13.3 Energy
in Ecosystems
• Herbivores – eat producers
• Carnivores – eat other consumers
• Omnivores – eat both producers and
consumers
• Detritivores – feed on the “garbage” of an
ecosystem
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
A food chain is a model that shows a single chain of
consumers within an ecosystem.
• arrows point in the direction that energy flows
GRAMA GRASS
DESERT COTTONTAIL
HARRIS’S HAWK
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
A food web - interrelated food chains in an ecosystem
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Energy Flow
moves from producers to consumers
Trophic level – indicates the organism’s position in the
sequence of energy transfers
• Producers – 1st trophic level
• Herbivores – 2nd trophic level
• Predators of herbivores – 3rd trophic level
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Quantity of Energy Transfers
10% of the total E consumed in one trophic level is incorporated
into the organism in the next level
• E is used to maintain body T, to move, etc.
• E is lost when organisms escape being eaten
– decomposer return their E to the lower trophic levels
• E is lost in parts of the organism that can not be broken down
by the predator
– bones, teeth, hair
13.1 Ecologists Study Relationships
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
An energy pyramid shows the distribution of energy
among trophic levels.
•Higher trophic levels contain less energy
• support fewer individuals
energy
lost
energy transferred
16.3
13.4
Food
Chains
Qualityand Study
Food Webs
13.1Water
Ecologists
Relationships
Biomagnification - accumulation of toxins in the food
chain.
• Pollutants move up the food chain.
– predators eat contaminated
prey
• Top consumers (humans) are
most affected.
• DDT- Birds of prey
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Species Interactions
Predation
• Predator – captures, kills, and consumes prey
– Influences where and how species live by determining
their relationship in the food web
– Regulates population size
Natural selection favors adaptations that improve the efficiency
of predators at finding, capturing, and consuming prey
Natural selection favors adaptations for prey to avoid, escape,
or otherwise ward off predators
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Natural selection of plants has favored
adaptations that protect them from being
eaten
• Thorns, sticky hairs, tough leaves
• Chemical defenses (secondary
compounds)
– Strychnine, nicotine, poison ivy
– May also have medicinal uses –
codeine, morphine
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Parasitism – one individual is harmed (host) while the
other benefits (parasite)
• Does not usually result in the immediate death of the host
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Ectoparasite – external parasites – do not enter hosts body
• Ticks, fleas, lice, leeches, mosquitoes
Endoparasite – internal parasite – live inside host
• Disease causing bacteria, protists, tapeworm
Affect the health and reproduction of the host
Stimulates evolution of defenses in hosts
• Tough skin & chemically defended openings
– eyes-tears
– mouth-saliva
– nose-mucus
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Natural selection favors adaptations that allow a
parasite to efficiently attack host
• Specialized anatomically
– Mouth parts
• and Physiologically
– Body chemistry to survive different environments etc.
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Competition
• The use of a limited resource by 2 or more species
• Types
– Intraspecific- competition between organisms of
the same species
– Interspecific- competition between 2 or more
different species of organisms
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Competitive Exclusion
• one species is eliminated from a community
• Natural selection favors differences between potential
competitors – character displacement
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Resource Partitioning
• Organisms “divide” resources
• Adaptations allow for use of resources in different
ways or at different times
• Examples
– Diurnal vs. Nocturnal
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Mutualism
Cooperative relationship in which both species benefit
• Some relationships are so close that neither species can
survive without the other
• Ex: pollination
13.1
Ecologists
Relationships
13.4 Food
Chains and Study
Food Webs
Commensalism
• Interaction in which one species benefits and the other is
not affected
13.1
Ecologists
14.1 Habitat
and NicheStudy Relationships
Niche -Role of a species in its environment
(Job)
Types:
– Fundamental- ideal; absence of competition
– Realized- natural; competition and other
constraints
13.1
Ecologists
14.1 Habitat
and NicheStudy Relationships
• Generalists are consumers that have a varying diet.
• Specialists are consumers that primarily eat one specific
organism or a very small number of organisms.
13.1
Ecologists
14.1 Habitat
and NicheStudy Relationships
Generalist
vs.
• Broad niche
• Tolerate variety of
resources and conditions
• Example
– raccoons
Specialist
• Narrow niche
• Very specific
adaptations
• Example
– Koalas
13.1
Ecologists
14.1 Habitat
and NicheStudy Relationships
A habitat is all aspects of the area in which an organism
lives.
– biotic factors
– abiotic factors