2. Ecology pt3 Flashcards
Define population
the total number of a species living at the same time in a specific place
Define community
all of the populations of the organisms (animals, plants, fungi, protista, prokaryotes) that are interdependent in a habitat
Define ecosystem
a community of organisms (biotic) interacting with the non-living elements (abiotic) of their environment
Define interdependent
the relationship between communities where the increase or decrease in the numbers of one, affects the whole community
Define competition
the combat between individuals to obtain resources
What happens when individuals of the same species compete?
It leads to natural selection
What happens when individuals of diffrent species compete?
could cause extinction
Define stable community and give 3 examples
a habitat with fairly constant environmental factors so that the number of species, and the populations of each species is balanced and relatively constant
give 3 examples of a stable community
- tropical rainforest
- ancient oak woodlands
- mature Coral Reefs
The ……. Of a species and the ……… Of each are affected by ……… And ……….. Factors
Distribution
Population
Biotic
Abiotic
List 4 biotic factors that affect communities
- availability of food
- new predators arriving
- new disease
- competition
Explain how the a availability of food affects communities?
- organisms can only live where their food source is
- if there is a lot of food they’re likely to reproduce
- if there’s not a lot of food they’re unlikely to breed and some many starve so the population will fall
Explain how a new predator arriving affects communities?
If a spices has poor defences against a new predator they’re likely to be killed off
Explain how a new disease affects communities?
A new parasite or pathogen can kill off a species, or just greatly reduce their numbers
Explain how competition affects communities?
If one species is much more successful at obtaining resources eg. Food, the less successful may die out in that area
Define Interspecific
Competition between different species
List 7 abiotic factors that affect communities
- light intensity
- temperature
- water/moisture levels
- soil PH and mineral content
- Oxygen availability
- wind intensity and direction
- carbon dioxide concentration
Explain how light intensity affects communities?
- it limits photosynthesis, and affects the distribution of plants
- some plants can tolerate low light (large leaves)
- some can only with high light intensity
- (biotic factor) plants are a food source for herbivores it will affect the distribution of animals
Explain how the temperature affects communities?
- limits photosynthesis, affects the distribution of plants and keeps then small in cold climates
- (biotic factor)plants are a food source for animals so affects there distribution too
Explain how water/moisture affects communities?
- both plants and animals need water
- only well adapted species can tolerate dry conditions
Explain how the soil PH and mineral content affects communities?
- all plants need nitrates to produce proteins and grow
- they also need minerals
- if the soil doesn’t have enough nutrients plants will die (unless adapted)
- If the pH is too low, plants can’t grow as it disrupts enzymes function
Explain how the oxygen availability affects communities?
- all plants and animals need oxygen to respire
- the concentration of oxygen in water can vary so can affect aquatic organisms
Explain how wind intensity and direction affects communities?
- strong winds can blow soil away and make it difficult for seeds to take root and grow
- it’s direction can affect the shape of growing plants
Explain how the carbon dioxide concentration affects communities?
- is needed for photosynthesis
- but generally the same everywhere in the atmosphere
