Chapter 3 Ecology Flashcards
Biosphere
consists of all life on earth and all parts of earth where life exists
Species
a group of similar organisms that can breed and produce fertile offspring
Population
a group of individuals that belong to the same species and live in the same area
Community
an assemblage of different populations that live together in a defined area
Ecosystem
all the organisms that live in a place, together with their physical environment
Biome
a group of ecosystems that share similar climates and typical organisms
Biotic Factor
any living part of the environment with which an individual might interact, inluding animals, plants, mushrooms, and bacteria
Abiotic Factors
any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, and soil type
What is ecology?
the scientific study of interactions among organisms and between organisms and their physical environment
What methods are used in ecological studies?
1) Observation2) Experimentation3) Modeling
What is an autotroph?
organisms that use solar or chemical energy to produce “food” by assembling inorganic compounds into complex organic molecules. (store energy in forms that make it available to other organisms that eat them)
What is a Primary Producer?
Autotrophs that store energy in forms that make it available to other organisms that eat them. The first producers of energy-rich compounds that are later used by other organisms.
Explain photosynthesis
most common in primary producers. Captures light energy and uses it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugar and starches.
What is chemosynthesis?
Light-independant organisms that use chemical energy to produce carbohydrates.
What is a heterotroph?
organisms that acquire energy from other organisms by ingestion
What is a consumer?
organisms that rely on other organisms for energy and nutrients
What are the 6 main types of consumers?
all heterotrophs, either primary or secondary1) Herbivores- eat plants2) Carnivores- kill and eat other animals3) Omnivores- variety of food including plants and animals4) Decomposers- “feed” by chemically breaking down organic matter5) Scavengers- consume carcasses of other animals6) Detritivores- eat detritus particles and the decomposers that live on them
What is a food chain?
a series of steps in which organisms transfer energy by eating and being eaten
What are phytoplankton?
mixture of floating algae which are aquatic primary producers
What are zooplankton?
diverse group of small, swimming animals that feed on marine algae (example= krill)
What is a trophic level?
each step in a food chain or food web
What is an ecologic pyramid? (what are 3 types?)
shows the relative amount of energy or matter contained within each trophic level in a given food chain or food web. 3 types include:1) pyramid of energy (relative energy available at each trophic level)2) pyramids of biomass (grams of organic matter/unit area at each trophic level)3) pyramids of numbers (relative # of individual organisms at each trophic level)
What is biomass?
The total amount of living tissue within a given trophic level. Measured in (grams of organic matter/unit area)
What is a biogeochemical cycle?
the passing of elements from one organism to the other among parts in the biosphere through closed loops which are powered by the flow of energy
What is a nutrient?
chemical substances that an organism needs to sustain life.
Which three pathways/cycles are vitally important for life?
1) Carbon cycle2) Nitrogen cycle3) Phosphorus cycle
Describe nitrogen fixation and how it can supply us with nitrogen.
changing an nitrogen in the environment into ammonia by bacteria. Soil bacteria convert to nitrates or nitrites. Once these forms of nitrogen are available, primary producers can use them to make proteins and nucleic acids. We can then consume those plants or even the animals which eat those plants. (or even the animals which eat the animals, which eat the animals which feed on the plants)
What is denitrification?
when nitrogen is released back into the atmosphere from a fixed chemical location. For example, some soil bacteria convert nitrates into nitrogen gas which releases back into the atmosphere
What is a limiting nutrient?
the nutrient whose supply limits productivity. If ample sunlight and water are available, the primary productivity of an ecosystem may be limited by the availability of nutrients.
Name the 3 main types of feeding relationships.
1) Producer - Consumer2) Predator - Prey3) Parasite - Host
What is an omnivore? (name 1 example)
consumer that eats both plants and animalsexamples: bears and humans
What is a carnivore?
Consumers that eat meat. Examples include both predators and scavengers
True or False, Predators and prey undergo coevolution.
True- Both evolve based on the other organisms phenotypic characteristics
What are the 3 types of symbiosis?
1) Commensalism - 1 species benefit, other is neutral2) Parasitism - 1 species benefit, other is harmed3) Mutualism- Both species benefit
As you move up the food chain/web, energy/biomass goes _________
Down- energy and biomass decreases at each trophic level
Carbon cycles through a system primarily by the means of what two processes?
photosynthesis and cellular respiration
The atmosphere is mostly composed of which gas?
Nitrogen gas (diatomic N2) 78-80% of air
What must be done to atmospheric Nitrogen before it can be used by organisms?
bacteria (or some industrial processes) must convert N2 into ammoniumN2 –> NH4+
Where do nitrogen fixing bacteria live?
some live in soil, some live on the root tips of plants like the symbiotic bean bacteria, some cyanobacteria live in semi-aquatic ecosystems
How do toxins propagate throught the food pyramid/web?
Toxins become amplified as you move up each trophic level
