Week Two Flashcards
What is Ecology?
Ecology is the study of how organisms interact with each other and the environment.
Why is ecology important?
Humans are changing the environment at a faster rate than at any time in the last 65 million years.
What are the two perspectives of which an environment is usually analyzed?
- Biotic: Organisms that are present
- Abiotic: Non-living, physical aspects that impact those organisms, such as temperature, mineral nutrients, wind, soil
- Together they make an ecosystem.
What is organism ecology?
Focuses on how individuals of the same species interact with each other and the environment. Focused often on animal and plant behaviour.
What is a population?
Defined as a group of individuals of the same species that live in the same area at the same time.
Define Species
A species is an evolutionary unit in nature. Species are comprised of one or more populations that evolve as a unit and share genetic and physical characteristics.
What are ecological communities?
Comprise the groups of species present in the same area at the same time.
How to calculate growth rate for organisms that breed continuously? (like humans)
Instantaneous rate of increased
What is exponential growth?
This is defined as any pattern of increase when r or lambda does not change over time.
Exponential growth in science menas that the population growth can be extremely slow or even non-existent, as long as r isn’t chaning.
What does it mean to become density dependent?
When growth becomes density dependent, this means that the population is unable to grow past a certain point because there is a challenge for resources to sustain the larger population.
Define carrying capacity?
Refers to the size of a population that a particular habitat can support over the long term, and is a function of the resources available.
What do species in a community do?
They actively interact in ways that affect each other’s distribution, abundance, and evolution. Community ecology is the study of those interactions
What are terrestrial communities named after?
They are named after the types of lands and plants present. Example: Alpine meadow community, a shortgrass prairie community.
What are ecosystem services?
The good and services that humans derive from the natural environment. Such as oxygen, drinking water, soils, carbon sequestration (storing of C02)
What is the concept of the niche?
Defined as the range of conditions a species lives in.
What is the fundamental niche?
The physical conditions that a species can tolerate. Defines the locations where it is physically possible for a particular species to live. Example: In a dry environment, humans die if the temperature is above 57 degrees Celcsius. But if the climate is humid that drops to 43 degrees.
What is the realized niche?
No species occupies its entire fundamental niche. Instead, each is found in a more limited range of conditions called the realized niche. This occurs because biotic interactions restrict where species are actually found. Examples:
1. Predation or herbivory eliminating species
2. Diseases caused by parasites
3. Mutualisms involving a strong beneficial interdependence between two species
4. Competition for space, nutrients, water.. etc.
What are the different sections of a realized niche?
- Parasitism causes disease
- Mutualism benefits both parties (increases fitness for both).
- Competition is about access to food, space or recources
- Predation and herbivory are about eating and being eaten
Different point of characterization of life history.
- The diagram is a continuum, not an either-or polarity. Most orgrnaisms fit somewhere in the blue-bar between fast and slow
- The characterizations of growth rate, age of reproduction, and maximum lifespan are all relative.
- There are many exceptions to the patterns of co-occuring fast-slow contrasts, meaning that species can have some “fast traits” and some “slow traits”
What is the level of ecology organization from the broadest classification to the most specific?
- Ecosystem
- Community
- Species
- Population
- Individual
What is a community?
Groups of different species present in the same place at the same time.
What to know about the finite rate (lambda)
Represents a ratio of the final population size to the beginning population size. The finite rate will always be greater than 0 as long as there is at least one individual in the population.
Lamda
lambda >1 The population is growing. This means that the birth rate is greater than the death rate.
lambda <1 The population is shrinking. This means that the death rate is greater than the birth rate.
lambda = 1 The population is stable. This means that the birth rate is equal to the death rate.
instantaneous growth rate (r)
a measure of how quickly a population is changing at a specific moment in time. It’s calculated by subtracting the per-individual death rate from the per-individual birth rate
What “r” means?
Positive r: The population is increasing
Zero r: The population is stable
Negative r: The population is decreasing
When calculating instantenous growth rate - what does “t” measure?
T - measures time - remember that it is the amount of time that past. So if 3 readings are calculated on days 0, 1, 2 –> t = 2
