Chapter 20 - Ecology Flashcards
What is ecology?
The study of the interactions between organisms and their environment
What does the environment encompass?
All that is external to the organism and is necessary for its existence
What are the 2 components of an organisms environment? What do they each include?
1) Abiotic: Non-living or physical environment
- Climate
- Temperature
- Light
- Water
- Local topology
2) Biotic: Living environment
- All living things that directly/indirectly influence of life of the organisms
- Relationships between organisms
What are the 5 levels of biological organization?
1) Organism: An individual unit composed of smaller units
- Contains organ systems
2) Population: Group of organism of the same species living together in the same location
- Species is any group of similar organisms that are capable of producing fertile offspring
3) Communities: Consists of populations of different plants and animal species interacting with each other in a given environment
- Biotic community: Includes only the population and not their physical environment
- Ecosystem: Includes the community and the environment (generally contains all 6 kingdoms)
4) Ecosystem: Encompasses the interaction between living biotic communities and the nonliving environment
5) Biosphere: Includes all portions of the planet that support life - atmosphere, lithosphere, hydrosphere
- Relatively thin zone that extends a few feet beneath the Earth’s surface several miles into the deepest sea, and several miles into the atmosphere
How are organs formed in an organism?
Formed from tissues, tissues are formed from cells, cells come from many different molecules, molecules from atoms, and atoms from subatomic particles
What are the 5 components of the physical environment?
1) Water: Major component of the internal environment of all living things - it can be readily available or the organism will possess adaptations for water storage/conservation
2) Temperature: Must be maintained at optimal level - organisms have necessary adaptations
- Depends on latitude and altitude
3) Sunlight: Ultimate source of energy for all organisms
- Photic Zone: Top layer of water which light can penetrate where all photosynthetic activity takes place
- Aphotic Zone: Only animal life and other heterotrophic life exists
4) Oxygen Supply: Air contains 20% oxygen
- Aquatic plants/animals utilize the small amount of oxygen dissolved in water
- Pollution can lower oxygen content in water and threaten life
5) Substratum: Soil or rock which determines the nature of plant/animal life in the soil
- Acidity/pH determines what type of plants grow
- Texture determines water holding capacity
- Minerals (nitrates and phosphates) affect vegetation
- Humus (decay plant/animal life in soil)
What the the niche? What factors must be considered? What is the overall concept of the niche?
It defines the functional role of an organism in its ecosystem (distinct from the habitat) where an organisms lies
- Describes what the organisms eats, where/how it obtains food, climatic factors it may tolerate/optimal, nature of its parasites/predators, how/where it reproduces, etc.
- Concept of niche embodies every aspect of an organisms existence
Can 2 organisms occupy the same niche?
No - they would compete for same resources
What about 2 organisms that occupy similar niches? Outcomes?
They would just utilize at least one resource in common, therefore just competing for that specific resource
Outcomes:
- One species may be competitively superior to another and drive the second to extinction
- One species may be competitively superior in some regions and the other may be super in other regions under different environmental conditions which would result in one species in some places and the other species in other places
- Two species may rapidly evolve in divergent direction under strong selection pressure resulting from intense competition, thus, both species would rapidly evolve greater differences in their niches
What are the 5 types of organisms that interact with the environment?
1) Autotrophs: Manufacture their own food
- Green plants = energy from the sun
- Chemosynthetic bacteria = energy from oxidation of inorganic sulfur, iron, nitrogen, etc.
2) Heterotrophs: Cannot synthesize own food and depend on autotrophs or other heterotrophs in ecosystem to obtain food/energy
3) Herbivores: Only consume plants/plant foods
- Long digestive plants for greater surface area and time for digestion
- Cannot digest most food they consume and rely on symbiotic bacteria to breakdown and utilize cellulose
4) Carnivores: Eat only other animals
- Canine fanglike teeth for eating flesh
- Short digestive tracts dur to easier digestibility of animal food
5) Omnivores: Eat both animals and plants
What are interspecific interactions of a community? What are the major types of interspecific interactions?
It is an integrated system of species that are dependant upon one another for survival
Major types:
1) Symbiosis: They live together in an intimate, permanent which may or may not be beneficial to both participants
- Obligatory: One orbit cannot survive without the other
2) Commensalism (+/o): One organisms benefits and the other is not affected
3) Mutualism (+/+): Both organisms derive some benefit
4) Parasitism (+/-): Parasite benefits at the expense of the host
- Parasites live with minimum expenditure of energy
5) Predation: Free-living organisms that feed on other organisms (includes carnivores and herbivores)
- Aids in controlled population
- Predator-prey relationships evolve towards a balance in which predator influence prey but not a threat to its survival
6) Saprophytism: Protists and fungi that decompose dead organism matter within the ecosystem
7) Scavengers: Animals that consume dead animals
- No adaptations for hunting or killing prey
What is infraspecific interactions?
Individuals belonging to the same species utilize the same resources and may have to compete with one another
What are 2 types of interactions between organisms and their environment?
1) Osmoregulation: Adaptations for maintaining their internal osmolarity and conserving water
- Saltwater fish drink and actively secret salt across gills
- Freshwater fish drink seldom and absorb salt through gills and excrete dilute urine
- Insects excrete solid uric acid crystal to conserve water
- Camal tolerante wide range of temperature and has fat layers that are exposed to solar radiation
- Horned toad has thick, scaly skin to prevent water loss
- Plants have waxy cuticles on surface and stomata on lower surface
2) Thermoregulation
a) Poikilothermic (cold blooded) animals/plants thermal heat escapes to the environment thus their body temperature is close to that of the environment, meaning their metabolism is radically affected by environmental temperature changes (high = active; low = sluggish)
b) Homeothermic (warm blooded) have evolved physical mechanisms to make use of heat produced as a consequence of respiration (i.e. hair, feathers, fat)
- Maintain body temperature higher than environment and are less dependant on environmental temperature changes because they can inhabit a wider range of environments
How can one explain or represent energy flow within the ecosystem?
All things require energy to carry on life functions - complex pathways are involved in the transfer of this energy which can be mapped in the form of a food chain or food web
What is a food chain? What does it consist of?
Food chain: Single chain showing the transfer of energy
Consists of
- Producers: Autotrophic green plants and chemosynthetic bacteria utilize energy of sun and simple raw materials, captured and stored in C-H bond; initial step in food chain
- Primary consumers: Animals that consume green plants (i.e. cow)
- Secondary consumers: Animals that consume primary consumers (i.e. carnivores; tigers)
- Tertiary consumers: Animals that feed on secondary consumers (carnivores)
- Decomposers: Saprophytic organisms and organisms of decay (fungi and bacteria)
