Concepts 1+3 Ecology

What is ecology?

the study of relationships between two organisms/ between an organism and its environment

What are the characteristics of life?

• be composed of one (unicellular) or more cells (multicellular)

• contain either DNA or RNA as their genetic material

• be capable of growth (develop and becoming larger)

• be capable of reproduction (producing offspring)

  • can be sexual or asexual

• demonstrate the ability to respond to outside stimuli

• as a population be able to adapt to the environment and evolve

  • populations of living things change over time

  • individuals don’t evolve, populations do

• have a metabolism, meaning both consume energy and produce waste

What is sexual reproduction?

2 parents produce genetically unique offspring together

What is asexual reproduction?

1 parent produces genetically identical offspring

What is a stimulus?

a change in an organism’s environment (cause)

What is a response?

how an organism reacts to a change in its environment (affect)

What is metabolism?

all of the chemical reactions of each cell in an organism that provide energy for life’s processes and create key molecules

What is an organism?

an individual member of a species or population

What is a population?

multiple organisms of the same species living together

What is a community?

multiple populations of different species living together

What is an ecosystem?

community plus all of the abiotic factors in the environment

What is a biome?

multiple ecosystems that share similar characteristics but are located in different parts of the planet

What is a biosphere?

the zone of life on Earth encompassing all of Earth’s ecosystems

What is biodiversity?

the variety of all organisms considered at all levels, from populations to ecosystem

What is taxonomy?

field of biology that classifies organisms, organizing them based on similar characteristics

What is all life organized into?

1. domain

2. kingdom

3. phylum

4. class

5. order

6. family

7. genus

8. species

What is binomial nomenclature?

a two name naming system by Carol’s Linnaeus that names organisms after their two most specific classification levels: genus species

What is a cladogram?

a diagram that shows relatedness of organisms

• does not show ancestral relationships like a phylogenetic tree does

What is a dichotomous key?

tool used for identifying organisms based on their characteristics

What is population density?

measures the number of individual organisms living in a defined space

What factors contribute to a high population density?

birth (natality) and immigration

What factors contribute to a low population density?

emigration and death (mortality)

What is a survivorship curve?

a graphic representation of mortality patterns

• shows the number of individuals in a population that can be expected to survive to any specific age

What is Type I survivorship?

late loss; heavy parental care

example: humans

What is Type II survivorship?

constant loss; mortality unaffected by age

examples: some birds, rodents

What is Type III survivorship?

early loss; produce lots of offspring at once and many die right away

examples: fish, mosquitos

What is population dispersion?

the spatial distribution of organisms in a population

• can be random, uniform/even, clumped

What is exponential population growth?

population grows without limit

example: human population

What is logistic population growth?

population grows quickly at first and then levels off

example: most natural populations (fish, rabbits, trees, etc)

What is carrying capacity?

the theoretical maximum population that a given environment could support

What are limiting factors?

aspects of the environment that limit the size a population can reach

• can be biotic (living) or abiotic (nonliving)

• can be density undefended or density dependent

What are density-dependent limiting factors?

have a bigger impact on more dense populations

• can be triggered by an increase in population size, and thus crowding

What are examples of density-dependent limiting factors?

• competition

• predation

• parasitism

• disease

What are density-independent limiting factors?

regulate population growth regardless of its size or density

• nearly all species are affected equally

What are examples of density-independent limiting factors?

• weather changes

• pollution

• natural disasters