Population Size✅ Flashcards
What is carrying capacity
The max size of a population
Describe a typical population growth curve
Slow growth (lag phase)
Rapid growth
Stable state (carry capacity) birth and death rate similar
What is definition and example of density dependent factors
The impacts of these factors vary with population density
Eg abiotic: temp, water availability, ph, light intensity, BIOTIC: predation, disease, competition, migration
Give definition and example of density independent factors
Factors that affect a population regardless of its size
Eg natural events (earthquakes, storms)
What is a limiting factor in context of populations
Factor that restricts the final size of a population
What is interspecific competition
Different species competing for resources, the competing species overlap in food sources, behavior or habitat they occupy
Better adapted species may outcompete other species if resources are limited
What is intraspecific competition
Members of same species competing for limited resources
What is conservation and what happens
The sustainable management of an ecosystem to maintain biodiversity.
Active, sustainable management (balancing maintenance of biodiversity with extraction of resources). Can Include reclamation (restoring damaged ecosystems)
What is preservation and what happens
Maintenance of ecosystems in their original state (without interference)
Ecosystems monitored, visitors not allowed, interference kept to a minimum
What are ethical, economical, social benefits of conserving ecosystems
Ethical: humans have moral responsibility
Social: aesthetically attractive, provide recreation, enable ecotourism, have educational benefit
Economic: organism harvested using sustainable approach, humans gain resources (food,drugs, timber),
Define sustainability
Use of natural resource without damaging biodiversity and ensuring that resource is not depleted
How is timber production done sustainably
Coppicing (tress getting cut close to ground and produce new shoots), can be rotational (region varies each year), trees are replanted
How is fishing done sustainably
Fishing quotas, fish farms
Give description of masai Mara and conservation methods
Savannah ecosystem, contains grassland and woodland, large populations of zebra buffalo elephants lion leopards
Promotion of ecotourism, prevention of rhino poaching, legal hunting
Give description of Terrai region and conservation methods
High temps+humidity in summer, fertile soils with lush forest, high biodiversity, heavy deforestation+agriculture use
Sustainable forest management, improved irrigation schemes (increase efficiency of agriculture production), encouragement of fruit+veg growing in nearby regions to relieve pressure of intensive farming on region
Give description of peat bogs and conservation methods
Ground with high water content+decomposing vegetation, natural stores of CO2,peat can be removed for use as a fuel to improve farm soils, contains rare species
Blocking ditches to prevent flooding, this raises water levels of peat bogs, removal of trees and prevention of afforestation
Description of Galápagos Islands and conservation methods
An environmentally sensitive ecosystem, contains unique
Limiting and managing tourism, strict controls over movement of introduced
define A: limiting factor, B: a density dependant factor (2 marks)
A: a factor that limits the maximum size of a population
B: a factor that affects population size, but its effects vary with population density
state 3 factors for which plant species are likely to compete (3 marks)
light
water (from the soil)
CO2
(named) mineral ions (from soil)
Corals, limpets and anemones are all filter feeders ( they strain food particles from water) with habitats on the ocean floor. Barnacles are filter feeders that have evolved the ability to form colonies on skin of whales and side of ships. Explain the benefit of barnacles of this ability (3 marks)
the filter feeders have the same ecological niche
they feed on similar food items
barnacles avoid competition
the competition is interspecific
describe the difference between conservation and preservation (2 marks)
conservation is active/manages an ecosystem/ requires interference
Tilapia fish are primary consumers. Salmon are tertiary consumers. Explain why the farming of tilapia is more sustainable then farming of salmon (2 marks)
Tilapia are lower down the food chain
Only a single energy transfer occurs (from producer to primary consumer)
Farming salmon requires depletion of wild (primary/secondary) fish populations to act as food for the salmon
suggest why reclamation of a habitat is difficult (2 marks)
sometimes it is unclear which species were present in the original community
understanding and restoring the original abiotic conditions may be difficult
succession takes a long time
describe what is meant by an environmentally sensitive ecosystem (1 mark)
an ecosystem that is especially vulnerable to environmental change/human interference
suggest why both conservation and preservation of peat bogs is difficult to achieve (3 marks)
preservation is usually impossible because so few peat bogs remain in there original state
peat bogs take a long time to form
there is a conflict between reclamation/ conservation and human activity (eg extraction of peat)
