Environment And Health Lecture 2

Front 1

Define biological evolution: (2)

Back 1

- genetic change in populations of organisms across generations
- may be random or directed by natural selection

Front 2

Define natural selection:

Back 2

- the process by which traits that enhance survival and reproduction are passed on more frequently to future generations than those that do not

Front 3

When did Darwin and Wallace propose natural selection as the mechanism of evolution?

Back 3

- 1858

Front 4

What are the four principles of natural selection?

Back 4

- organisms face a constant struggle to survive and reproduce
- organisms tend to produce more offspring than can survive
- individuals of a species vary due to genes and the environment
- some individuals are better suited to their environment and will pass on their genes

Front 5

What is an adaptive trait?

Back 5

- a trait that promotes reproductive success

Front 6

What is a mutation?

Back 6

- accidental changes in DNA that may be passed on to the next generation

Front 7

What is:
a) directional selection
b) stabilizing selection
c) disruptive selection

Back 7

a) drives a feature in one direction
b) produces intermediate traits, preserving the status quo
c) traits diverge in two or more directions

Front 8

Define biological diversity:

Back 8

- an areas sum total of all organisms

Front 9

Define species:

Back 9

- a population or group of populations whose members share characteristics and can freely breed with one another and produce fertile offspring

Front 10

Define population:

Back 10

- a group of individuals of a species that live in the same area

Front 11

How many mass extinction events have occurred? (2)

Back 11

- five
- humans are causing the sixth

Front 12

What are the different levels of ecology? (5)

Back 12

-biosphere
- ecosystems
- communities
- populations
- organisms

Front 13

Define the biosphere:

Back 13

- the total living things on earth and the areas they inhabit

Front 14

define an ecosystem:

Back 14

- communities and the nonliving material and forces they interact with

Front 15

Define population ecology:

Back 15

- investigates the quantitative dynamics of how individuals within a species interact

Front 16

Define community ecology:

Back 16

- focuses on interactions among species

Front 17

What is population distribution (dispersion) and what are the different kinds found in nature? (4)

Back 17

- spatial arrangement of organisms within an area.
- random
- uniform
- clumped (most common)

Front 18

What is the growth rate formula?

Back 18

= (crude birth rate + immigration rate) - (crude mortality rate + emigration rate)

Front 19

What are limiting factors of population growth? (2)

Back 19

- physical, chemical, and biological characteristics that restrain population growth
- water, space, food, predators and disease

Front 20

What is environmental resistance?

Back 20

- all limiting factors taken together

Front 21

What are the important features of carrying capacity?

Back 21

- max population size of a species in an environment
- s- shaped logistic growth curve

Front 22

What are examples of density-dependent factors?

Back 22

- predation risk and competition for mates increases with density

Front 23

Examples of density independant limiting factors:

Back 23

- floods, fires, landslides

Front 24

What aspects are included in the study of ecosystems? (2)

Back 24

- all abiotic and biotic components
- energy flows, matter cycles

Front 25

Define net primary production: (2)

Back 25

- energy remaining after respiration, and is used to generate biomass
- available for heterotrophs

Front 26

What is a nutrient source?

Back 26

- reservoirs of nutrients that release more nutrients than they accept

Front 27

What is a nutrient sink?

Back 27

- reservoirs of nutrients that accept more nutrients than they release

Front 28

Define nitrification (2)

Back 28

-bacteria that convert ammonium ions first into nitrite ions then into nitrate ions
- plants can take up these ions

Front 29

What are denitrifying bacteria?

Back 29

- bacteria that convert nitartes in soil or water to gaseous nitrogen, releasing it back into the atmosphere

Front 30

What is the haber-bosch process? (2)

Back 30

- synthetic production of fertilizers by combining nitrogen and hydrogen to synthesize ammonia
- humans fix as much nitrogen as nature does

Front 31

What is eutrophication?

Back 31

- the process of nutrient over enrichment, blooms of algae, increased production of organic matter and ecosystems degradation