Ecology Part 2

Question 1

Energy Transfer/Flow in Ecosystems

Answer 1

Energy enters in the form of sunlight and is lost through heat.

Light Energy —> Chemical Energy —> Trapped in Organic Molecules. (Photosynthesis)

Question 2

Productivity of Ecosystems

Answer 2

Productivity is the measure of how effective a particular community is at converting the sun’s energy.

Depends on abiotic factors.

Question 3

Detritivores and Decomposers

Answer 3

Detritivore: Feed on dead and decaying plants and animals.
(e.g. vultures)
Decomposer: Micro-organisms that break down organic compounds into inorganic compounds so producers can absorb them. (e.g. fungi/bacteria)

Question 4

Energy flow in a Food Chain

Answer 4

Energy flows up a food chain via different trophic levels.

Roughly 10% is lost going up each level (lost as heat or used in homeostasis).

Question 5

Biomass

Answer 5

The total weight of living matter in a community.

Question 6

Introduced Species

Answer 6

The introduction of a new species to an ecosystem which has a dramatic effect on population dynamics of existing species. (very yappable)

Question 7

Key Features of Populations

Answer 7

1. Size: Number of individuals in an area.
2. Density: Measurement of pop per unit area / volume.
   Pop Density = no. individuals / unit of space
3. Dispersion: the spacing of organisms relative to each other (clumped, uniform, and random)

Question 8

Growth Rate

Answer 8

Population Growth (r) = (b + i) - (d + e)
——————————————————
Rate of Natural Increase (r) = Birth Rate (b) - Death Rate (d)

Question 9

Factors that affect Population Density

Answer 9

Immigration: movement of individuals into a population
Emigration: movement of individuals out of a populations

+ Density-Dependent/Independent Factors

Question 10

Density-Dependent Factors

Answer 10

Biotic factors in the environment that have an increasing effect as population size increases. (e.g. predation, disease, competition, parasitism)

Question 11

Density-Independent Factors

Answer 11

Abiotic factors in the environment that affect populations regardless of their density. (e.g. temperature, weather events, unpredictable catastrophic events)

Question 12

Population Growth

Answer 12

1. Exponential Growth: population increases over time (J curve).
2. Logistic Growth: population increases until carrying capacity is reached, then stabilises (S curve).

Question 13

Carrying Capacity (k)

Answer 13

The maximum population size that can be supported by available resources.

Question 14

Factors limiting growth rate

Answer 14

food supply
toxic waste
disease
predation
competition
(yap)

Question 15

“R” Strategy

Answer 15

short lifespan, fast reproduction, neglectful parents, smaller body.
(e.g. cockroaches)
very volatile population growths

Question 16

“K” Strategy

Answer 16

long lifespan, slow reproduction, good parents, larger body.
(e.g. elephants, humans)
stable population growths

Question 17

Biodiversity

Answer 17

Includes ecosystem, species, and genetic diversity.

Ecosystems with high diversity are more stable and are less likely to be disrupted by environmental changes.

Question 18

Ecosystem Diversity

Answer 18

A wide range of different habitats to provide resources and shelter.

Question 19

Species Diversity

Answer 19

A wide range of different species present in an ecosystem.

Question 20

Genetic Diversity

Answer 20

The range of genetic characteristics of a species.

Greater genetic diversity allows a population to adapt to changing environments.