Chapter 25, Evolution of Life Flashcards Preview

BioSci 1223 (S&T) > Chapter 25, Evolution of Life > Flashcards

Flashcards in Chapter 25, Evolution of Life Deck (31):
1

What are the four groups of eukaryotes we will study?

Protists, Fungi, plants, and animals

2

When was the earth formed?

4.6 BYO

3

Describe the bias in the fossil record

Not all species are represented equally, there is bias toward those that existed for a long time, were abundant and widespread, and had hard parts such as shells or skeletons

4

Describe radiometric dating

A method used to date fossils using the characteristic rate of decay (half-life) of a parent isotope to its daughter

5

How do we date fossils younger than 75,000 years?

The half-life of C-14

6

How do we date fossils older than 75,000 years?

Isotopes like U-238 are used to date the volcanic rock layers above and below the fossil

7

What are the three most recent eras?

Paleozoic, Mesozoic, Cenozoic

8

What marks the start of the 1st era?

Cambrian explosion-> Paleozoic

9

What was the name of the first prokaryotes? Describe them. When did they appear?

Stromatolites, bacterial mats that lived during the Archaean

10

What was the first eukaryotic organism? When was it?

Red algae, Proterozoic

11

When did the first multicellular eukaryotes appear? What were they?

Proterozoic, sponges and cnidarians

12

When was the age of the dinosaurs?

Mesozoic

13

When was the age of the mammals?

Cenozoic

14

When did atmospheric oxygen first start to rise? Who produced it? What was its effect on the life already present?

Archaean, cyanobacteria, killed many of the prokaryotes but some others used it for cellular respiration

15

When was land colonized? Who colonized it?

Start of Phanerozoic, arthropods (insects)

16

When did humans appear?

Cenozoic

17

What is an endosymbiont?

A cell that lives within a host cell

18

How did eukaryotes get their mitochondia?

A archaean engulfed an aerobic bacterium

19

Describe the theory of serial endosymbiosis. What are some pieces of key evidence to support this theory?

Mitochondria evolved before plastids through a sequence of endosymbiotic events

Inner membranes are similar to plasma membranes, DNA and cell division is similar to bacteria, both transcribe and translate their own DNA, ribosomes are more similar to bacteria

20

How did eukaryotes get their nucleus?

Infolding of the plasma membrane

21

How did eukaryotes get a plastid?

A heterotrophic ancestral eukaryote engulfed a photosynthetic bacterium

22

What is the Edicaran biota?

An assemblage of larger and more diverse soft-bodied organisms that lived from 635 to 541 MYA

23

When were the first real predator-prey interactions?

Cambrian explosion

24

Why did fungi and plants colonize land together?

Plants work with fungi for increased surface area and nitrogen/carbon fixing

25

Describe the first plants. What was their major limitation?

Mosses, lichens and liverworts were the first plants, but they had to rely on diffusion to transport water due to their lack of vascular tissue and were very small

26

Describe the second group of plants. What improvements did they have?

Ferns were the first vascular plants, so they could grow larger but still needed water to reproduce

27

Define mycorrrhizae

Mutually beneficial relationships between plants and fungi

28

How many mass extinctions occurred before humans formed?

5

29

How do foraminifera found in rock layers above the K-T boundary compare to those in rock layers above?

Those above the boundary are smaller and less diverse than those below

30

Why were scientists slow to accept the asteroid impact hypothesis?

At the time, most geologists thought that the Earth changed slowly and gradually, and not by major catastrophes

31

What are the four major eons?

Hadean, Archaean, Proterozoic, Phanerozoic