ecosystems Flashcards

Question

define competition and give an example

Answer 1

Different species can share the same habitat and food requirements. Competition is the struggle between organisms to survive as they attempt to use the same limited resource. In any ecosystem, there is a limited amount of food, water and shelter. Organisms that survive have adaptations that enable them to reduce competition. eg cheetahs and lions

Answer 2

``` Availability of water Availability of food Temperature Availability of space Availability of mates ```

Answer 3

consume producers only.

Answer 4

consume consumers

Answer 5

consume both producers and consumers.

Answer 6

consume dead or decaying organic matter. - Saprotrophs do this by the secretion of extra-cellular enzymes. Fungi are examples of saprotrophs

Answer 7

organisms working together eg wolves (packs)

Answer 8

an organism that fills both niches eg chimpanzee, bears

Answer 9

Predation is an interaction in which one organism kills another for food. The organism that does the killing for food is the predator. The organisms that is killed for food is the prey. ion and zebra, bear and fish, and fox and rabbit

Answer 10

Carnivores – kill the prey during attack Herbivores – remove parts of many prey, rarely lethal. Parasites – consume parts of one or few prey, rarely lethal. Parasitoids – kill one prey during prolonged attack.

Answer 11

When one organism benefits by harming the other. Examples include Mosquitos, leeches, mistletoe. Fairly common but not predominant. - Plants and mistletoe

Answer 12

Where one organism benefits and the other is unaffected. Examples include cacti and desert eagles. Relatively uncommon. Where both organisms gain from the symbiotic relationship. Examples include coral and algae. Very common.

Answer 13

where both organisms benefit. eg Crabs & Sponges

Answer 14

producers and decomposers

Answer 15

The producers, consumers, and decomposers of each ecosystem make up a food chain.There are many food chains in an ecosystem. Food chains show where energy is transferred and not who eats who.

Answer 16

trophic level is the position occupied by an organism in a food chain. Trophic levels can be analysed on an energy pyramid.

Answer 17

first trophic level

Answer 18

second trophic level

Answer 19

third trophic level

Answer 20

top trophic level

Answer 21

down the bottom with producers

Answer 22

Energy is sometimes considered in terms of biomass, the mass of all the organisms and organic material in an area. There is more biomass at the trophic level of producers and fewer at the trophic level of tertiary consumers. (There are more plants on Earth than there are animals.)

Answer 23

Sample - “A portion, piece, or segment that is representative of a whole” - it is usually impossible to measure the whole - That the sample is representative of the whole - It is necessary to take enough samples so that an accurate representation is obtained - It is important to avoid bias when sampling

Answer 24

The number of organisms per unit area

Answer 25

– How fast a given population grows – Factors that influence this are: • Natality ( birth rate) • Mortality ( death rate) • Emigration (the number of individuals moving away a population) Immigration (the number of individuals moving a population)

Answer 26

– Factors that limit population size, regardless of population density. – These are usually abiotic factors – They include natural phenomena, such as weather events Drought, flooding, extreme heat or cold, tornadoes, hurricanes, fires, etc. – Any factor in the environment that depends on the number of members in a population per unit area – Usually biotic factors – These include; Predation, Disease, Parasites, Competition

Answer 27

The limit to population size that a particular environment can support

Answer 28

Also called geometric growth or J-shaped growth. • First growth phase is slow and called the lag phase • Second growth phase is rapid and called the exponential growth phase

Answer 29

a measure of production outcome of production = biomass rate of which biomass is produced per unit area (square metres over time)

Answer 30

``` Often called the S-shaped growth curve • Occurs when a population’s growth slows or stops following exponential growth. • Growth stops at the population’s carrying capacity • Populations stop increasing when: – Birth rate is less than death rate (Birth rate < Death rate) – Emigration exceeds Immigration (Emigration > Immigration) ```

Answer 31

As population grows, competition increases. • Usually biotic- food, disease, mates • Interspecific- competition between two different species – Predator-prey oscillations – Resource partitioning • Intraspecific - competition between individuals of the same species – Survival of the fittest • Stress/Crowding- stress-related diseases are more prevalent in a weakened population – Reduced fertility, low disease resistance, hypo-activity, hyperactivity, aggression, lack of parental care, cannibalism

Answer 32

1. Have a Boom-and-Bust Life Cycle 2. Have short life spans 3. Produce many offspring 4. Smaller organisms • i.e., fruit flies, mice, locusts 5. Don’t maintain a population near carrying capacity 6. Controlled by density-independent factors • They are called r-strategists (for rate of increase)

Answer 33

1. Have long life spans 2. Produce few offspring that have a better chance of living to a reproductive age 3. Are larger organisms • i.e., elephants 4.Maintain a population at or near k 5.Controlled by density-dependent factors • They are called k-strategists (for karrying kapacity)

Answer 34

eat dead matter, producer

Answer 35

the number of individuals of each species is counted and recorded, or the relative numbers of each species is estimated using a scale from abundant (3) to absent (0), or percentage cover is estimated, and the totals of the quadrats are averaged.

Answer 36

A transect is a line drawn through a community and the information gathered is used to determine the distribution of species within that community. There are two types of transects: 1. Line transects 2. Belt transects.

Answer 37

Species that touch the line (usually a piece of rope or tape) are counted. Advantages: simple, quick, minimal effort, gives you a good idea of distribution patterns and changes over distance such as plant density from the beach moving inland. Disadvantage: doesn’t give you an accurate idea of the number and proportion of species .

Answer 38

Uses a combination of quadrats and transect. Advantages: gives more detailed information including patterns of distribution AND abundance of different species. Disadvantage: takes more time and effort. Some ecosystems are difficult to assess because of topography. E.g. dense jungle.

Answer 39

total no. of individuals counted / area of each quadrat x no. of quadrats

Answer 40

Capture–mark–recapture is used to sample mobile species (animals). A random sample of individuals of a species is taken and an overall estimation of the abundance of the species is made.