Lecture 1

Question 1

9 Major characteristics of life

Answer 1

1. Biological and ecological hierarchy to life
2. Living organisms are made up of cells
3. Living organisms are organized
4. Life requires energy transfer & transformation
5. Cells/organisms reproduce
6. Cells/organisms/ecosystems grow & develop
7. Cells/organisms interact with their environment: 8. respond to stimuli
8. Cells/organisms/ecosystems maintain homeostasis
9. Organisms form populations that can evolve & adapt

Question 2

Biological organization:

Answer 2

atom→molecule→macromolecule→organelle→cell→tissue→organ→organ system→organism
Chemical level: atoms, molecules, organelles

Question 3

Biological organization of humans at different levels

Answer 3

Cellular level: single cell
Tissue level: groups of similar cells
Organ level: contains two or more types of tissues
Organ system level: organs that work closely together
Organismal level: all organ systems combined to make the whole organism

Question 4

Ecological organization:

Answer 4

Population→community→ecosystem→biosphere

Question 5

Population:

Answer 5

group of individuals of the same species, living in the same area

Question 6

Community:

Answer 6

all populations of organisms living in a particular area at the same time

Question 7

Ecosystem:

Answer 7

a community + its nonliving, physical environment

Question 8

Biosphere:

Answer 8

all of the ecosystems on Earth

Question 9

characteristics of cells

Answer 9

The cell is the smallest unit considered to be alive (organelles are not alive)
All new cells come from preexisting cells
Humans are made up of about 50 trillion cells
Unicellular or multicellular

Question 10

Cells do:

Answer 10

Metabolism: all reactions to build up or breakdown molecules, cells, tissues
Maintain homeostasis

Question 11

Living organisms get their energy from?

Answer 11

the sun or by consuming other organisms.

Question 12

Self sufficient ecosystem:

Answer 12

producers, consumers, decomposers

Question 13

types of reproduction

Answer 13

Asexual reproduction: mitosis

Sexual reproduction: occurs through fusion of gametes, meiosis

Question 14

growth vs development

Answer 14

Grow: size &/or number of cells. Mostly through the reproduction of cells (mitosis)

Development: all the changes that take place during an organism’s life

Question 15

definition of stimuli

Answer 15

physical or chemical change in the internal or external environment

Question 16

physical and biological stimulus?

Answer 16

Physical environment: abiotic component

Biological environment: other living organisms

Question 17

Homeostasis:

Answer 17

maintenance of a relatively stable internal environment despite continuous changes in the external environment. It’s a dynamic state of equilibrium, always readjusting as needed

Question 18

what is homeostasis defined at cell level and organism level

Answer 18

At level of the cell:
- pH, water content, levels of ATP

At level of the organism:

• Huge temperature changes outside→minimal changes in body temperature
• Amount of sugar & other nutrients: huge changes throughout the day→small changes in blood levels
• Other variables that change, but only slightly: blood volume, pH of blood, O2 and CO2 levels

Question 19

Negative feedback:

Answer 19

Regulatory mechanism that returns a variable to its target value
Reverses the direction of change to re-establish target conditions and so maintain homeostasis.

Question 20

Positive feedback:

Answer 20

Loop in which the response enhances the original stimulus: move further away from starting point, not back to it
Usually controls infrequent events that do not require continuous adjustment

Question 21

Evolution: unity and diversity of life

Answer 21

Change in environment
Those best suited to change survive
Offspring (descendants) have these traits

Question 22

The characteristics of life point to 5 common themes

Answer 22

1. Organization theme: life is organized in such way that at each level it becomes more complex, and new properties emerge
2. Information theme: expression and transmission of genetic information: genes are expressed, DNA is passed from one generation to next
3. Energy and matter theme: transfer and transformation of energy and matter: at the cellular level and at the ecosystem level (producers, consumers, decomposers)
4. Interaction theme: cellular level: + and - feedback. Organismal level: cells interact with each other. Ecosystem level: organisms interact with each other and their physical environment
5. Evolution theme: populations of living organisms can evolve, resulting in both unity of features and diversity

Question 23

how many species currently living

Answer 23

2 million species currently living

Question 24

Taxonomy:

Answer 24

naming and classifying organisms

Question 25

3 domains:

Answer 25

prokaryotic cells (bacteria and Archaea), eukaryotic cells (Eukarya)

Question 26

4 kingdoms:

Answer 26

fungus, plant, animal, protistan kingdoms

Question 27

Taxonomic classification is hierarchical:

Answer 27

Domains→Kingdoms→Phyla→Classes→Orders→Families→Genera→Species

Question 28

do prokaryotic cells have mitochondria

Answer 28

no.