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ECOLOGY 1st part
Transcript of ECOLOGY 1st part
An introduction to ecology and the biosphere
The scope of ecology
Human impact on ecosystems and the biosphere
The three levels of biodiversity are genetic diversity, species diversity, and ecosystem diversity
Biodiversity consists of the various kinds of ecosystems, the species richness of communities in those ecosystems, and the genetic variation within and between populations of each species.
Interspecific interactions and community structure
Factors affecting distribution of organisms
The scientific study of interactions between organisms and their environments.
The interactions between organisms and their
determine the distribution and abundance of organisms
Ecological research ranges from the adaptations of individual organisms to the dynamics of the biosphere
All the organisms that are part of the individual's environment
Pathogens, parasites, predators, competitors, food availability
All the the chemical and physical factors
Temperature, light, water, and nutrients
# identify 5 biotic and 5 abiotic factors in the school
• Species dispersal contributes to the distribution of organisms
Transplanted species may disrupt the ecosystem at the new site, even causing the extinction of native species.
• Behavior and habitat selection contribute to the
distribution of organisms A species may use only a subset to the habitat in which it could survive.
affect the distribution of organisms
Biotic factors involve interactions with other species, as in predation and competition.
affect the distribution of organisms
Among important abiotic factors are temperature, water, sunlight, wind, and rocks and soil.
• Temperature and water are the major climatic factors determining the distribution of organisms
Global patterns of distribution are set by climate and seasonality, which reflect the input of solar energy and Earth’s rotation around the sun.
Disturbance and community structure
Populations may be linked by competition, predation, mutualism, and commensalism
Individuals of different species compete for the same limited resources (food, water, shelter, etc.)
- two species competing for the same resource cannot coexist in the same place
One species will use the resources more efficiently and reproduce more rapidly.
- a species use of the biotic and abiotic resources
- use of different niches to avoid competition
One species (predator) kill and eat the other (prey)
, in which an herbivore eats part of a plant, and
, in which a parasite lives on or in its host organism and depends on the host species for nutrition.
Predators have adaptations to help to catch and kill their prey.
Prey have adaptations to avoid capture
An organism eats parts of a plant or algae
Many herbivores have special adaptation to identify whether or not plant toxicity and nutrition
Plants use defenses such as toxins or structures (spines, thorns)
One organism (parasite) obtains nutrients from another organism (host) which is harmed
Endoparasites - live inside the host
Ectoparasites - live on the surface of the host
Parasites can significantly affect the survival, reproduction, and density of the host species
Both species benefit
Obligate mutualism - one species cannot survive without its partner
Facultative mutualism - both species can survive alone
One species benefits and the other is neither helped nor harmed
Difficult to identify in nature because there may be a slight benefit or slight harm
(from the Greek word for "
") is the term used to describe ecological relationships between organisms of different species that are in direct contact.
# Is predation a type of symbiosis? Why or why not?
is a key factor in community dynamics
Feeding relationship in a community
Autotrophic organisms - primary producers
Herbivores - primary consumers
Carnivores - secondary, tertiary, and quaternary consumers
- transfer of energy from one organism to another
- all of the feeding relationships within a community
Limits on food chain length
- food chains are limited by the inefficiency of energy transfer from organism to organism
only about 10% of the energy is passed to the next trophic level
Dynamic stability hypothesis
- long food chains are less stable than short food chains
population fluctuations at lower levels are magnified at higher levels
top predators are most affected
The structure of a community may be controlled
by nutrients or
exert strong controls on community structure
most abundance with high competitive ability
has a pivotal ecological niche, often top predators
Ecology and evolutionary biology are closely related science
Ecological succession is the sequence of community changes after a disturbance
# What would happen to the other organisms if squids were removed from the ecosystem?
Trophic relationships determine the routes of energy
in an ecosystem
Energy and nutrients pass from primary producers (autotrophs) to primary consumers (herbivores) and then to secondary consumers (carnivores).
Energy flows through an ecosystem, entering as light and existing as heat. Nutrients cycle within an ecosystem.
Decomposition connects all trophic levels
Decomposers, mainly bacteria and fungi, recycle essential chemical elements by decomposing organic material and returning element to inorganic reservoirs.
Discover why a high diversity of species sustains ecosystems, which in turn provide important services to humans.
A wealth and variety of species, or species richness, promote strong ecological networks and functions, making ecosystems more resilient to major disturbances and collapse.
1. After watching the first tutorial, your friend turns to you and says, “Oh, I see! All interactions within an ecosystem network are the same importance, because all species have the same interactions with other species.” Do you agree or disagree with your friend’s statement? Explain why in a few sentences.
2. Which of the following network diagrams illustrates the most stable ecosystem? Explain your answer in a few sentences.
3. The table below shows the data your team collected while documenting the biodiversity on three islands. Based on these results, which of the islands should be categorized as having the greatest biodiversity, using the criterion of species richness? Explain your answer in 2-3 sentences.
4. Based on what you saw in the video, explain in 2-3 sentences why the whale in the whale fall scenario is similar to the Google server, in terms of their importance to their networks.
Healthy ecosystems provide crucial direct, indirect, and aesthetic-ethical benefits to humans.
1. What are the three categories of services that humans receive from healthy, diverse ecosystems? Provide an example for each category.
2. Consider the following statement, “Food, shelter, and energy are all examples of indirect services provided by ecosystems.” Do you agree or disagree with this statement? Explain why in 2-3 sentences.
3. Are coastal mangrove forests and commercial shrimp farms equal in their economic value to humans? Explain your answer in 2-3 sentences.
HIPPO + C
how does climate change affect biodiversity?