5A2 Reproductive Strategies and Population Growth Flashcards
Recognize the pros and cons of sexual and asexual reproduction. Explain how growth patterns and carrying capacity influence ecosystems.
Define:
Dispersal
The spread of organisms to new areas through immigration and colonization.
How might dispersal occur for immobile species?
It can occur through passive means such as wind or water.
How do immobile aquatic species like barnacles and corals solve the dispersal problem?
They release sperm and eggs into the water in a coordinated fashion with the rest of their population, resulting in millions of zygotes that develop into mobile or free-floating larval forms.
How do terrestrial plants disperse their seeds?
Some release seeds or spores to be carried long distances by wind and air currents, while others rely on animals to spread their seeds.
What is the difference between dispersal and dispersion?
- Dispersal refers to the actual process by which organisms spread.
- Dispersion describes the pattern in which organisms are already spread within a population.
List the three types of dispersion patterns.
- Uniform
- Clumped
- Random
Define:
Uniform dispersion
Organisms equally distanced from each other in an orderly pattern, typically the result of intraspecific competition.
Define:
Clumped dispersion
Organisms crowding near one another, usually the result of crowding around pockets of available resources.
Define:
Random dispersion
When organisms exist without a specific observable pattern, often due to ample resources and little competition.
Explain the concept of habitat fragmentation and its impact on dispersal and populations.
It is the process of breaking up large habitats into smaller, isolated pieces. It affects dispersal, immigration, colonization, and populations by limiting movement, gene flow, and access to resources.
Define:
Colonization
The establishment of a population in a new area.
Define:
Immigration
The movement of individuals into a population or area.
How does immigration relate to colonization?
If immigration occurs in an area not already occupied by that species, it can result in colonization, where the organism starts a population in a new habitat.
Summarize Island biogeography and its significance.
- It is the study of the distribution and abundance of species on islands.
- It provides insights into species diversity, extinction rates, and colonization patterns.
What factors does the Island biogeography theory focus on to estimate species diversity?
The size of the habitat and the distance from a source of species.
How does the Island biogeography theory predict species diversity on islands?
The theory predicts that larger islands and islands closer to the mainland will have greater species diversity than smaller islands or those further away from the mainland.
What is the significance of the Island biogeography theory in ecology?
It serves as a basis for predicting species diversity on islands and has inspired other ecologists to develop more complex theories related to species diversity, colonization, and population survival.
What is the equilibrium point in the Island Biogeography theory and what does it represent?
It represents the balance between colonization and extinction and predicts the number of species that can be found on the island.
What is an r-selected species and why is it called that?
It exhibits high reproductive rates followed by high mortality rates that lead to populations with highly fluctuating numbers.
R-selected species have very low parent involvement and typically a short lifespan.
Examples: Rabbits, jellyfish, bacteria
What is K- selected species?
They produce fewer offspring but spend a lot of time and resources ensuring that those few offspring make it to adulthood.
Low juvenile mortality rates, typically long lifespan.
Examples: Humans, elephants, whales.
What does the ‘K’ in K-selected species stand for?
Carrying capacity
K-selected species tend to stay close to carrying capacity.
What is the main difference between r-selected and K-selected species?
- r-selected species have populations that fluctuate wildly as a result of high birth rates followed by high mortality rates.
- K-selected species have more stable populations with low birth rates and low mortality rates.
What is exponential growth in Biology?
Growth with a constant per capita growth rate.
What does exponential growth produce in a population?
Values that ‘snowball,’ so the total rate of change keeps increasing without bounds.
