ZOO503 Merged PPT Handouts

Topic no 1 to 80 mid term and 81 to 165 final term syllabus · ZOO503 Zoogeography and Paleontology · Paleontology as a science: Paleontology in the modern world · Paleontology as a science

Paleontology in the modern world

What is Paleontology?

The branch of science concerned with fossil animals and plants. It is the study of fossils to determine organisms' evolution & ecology.

The Word Originates from Greek “palaios-old”, “ontos-creature" “logos-study" and Paleontology lies on the border between Biology and Geology. The fossils are present in the layers of earth and on the different areas of the earth. This is why the geology is of great importance in studying paleontology.

Use of Paleontology

1. Origin of life:

In the modern world the paleontology is being used for studying origin of life. Paleontology is study of old creatures and we further go in the past we can infer how the life originated in the first place. People want to know where life came from, where humans came from, where the Earth and universe came from. These have been questions in philosophy, religion and science for thousands of years and paleontologists have a key role. Despite the spectacular progress of paleontology, earth sciences and astronomy over the last two centuries, many people with fundamentalist religious beliefs deny all natural explanations of origins – these debates are clearly seen as hugely important.

2. Curiosity about different worlds

How different environment give rise to different organisms. We can speculate about how a life form could evolve in a world which is different from our world. Science fiction and fantasy novels allow us to think about worlds that are different from what we see around us. Another way is to study paleontology – there were plants and animals in the past that were quite unlike any modern organism. Just imagine land animals 10 times the size of elephants, a world with higher oxygen levels than today and dragonflies the size of seagulls, a world with only microbes, or a time when two or three different species of humans lived in Africa!

3. Climate and biodiversity change

Thinking people, and now even politicians, are concerned about climate change and the future of life on Earth. Much can be learned by studying the modern world, but key evidence about likely future changes over hundreds or thousands of years comes from studies of what has happened in the past. For example, 250 million years ago, the Earth went through a phase of substantial global warming, a drop in oxygen levels and acid rain, and 95% of species died out might this be relevant to current debates about the future?

4. The shape of evolution

The tree of life is a powerful and all-embracing concept – the idea that all species living and extinct are related to each other and their relationships may be represented by a great branching tree that links us all back to a single species somewhere deep in the Precambrian. Biologists want to know how many species there are on the Earth today, how life became so diverse, and the nature and rates of diversifications and extinctions. It is impossible to understand these great patterns of evolution from studies of living organisms alone.

5. Extinction

Fossils show us that extinction is a normal phenomenon: no species lasts forever. Without the fossil record, we might imagine that extinctions have been caused mainly by human interactions.

6. Dating rocks

Biostratigraphy, the use of fossils in dating rocks, is a powerful tool for understanding deep time, and it is widely used in scientific studies, as well as by commercial geologists who seek oil and mineral deposits. Radiometric dating provides precise dates in millions of years for rock samples, but this technological approach only works with certain kinds of rocks. Fossils are very much at the core of modern stratigraphy, both for economic and industrial applications and as the basis of our understanding of Earth’s history at local and global scales.

2 Paleontology as a science: What is Science?

Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. From Latin scientia, meaning "knowledge” Science is supposed to be about reality, about hard facts, calculations and proof. In mathematics, and many areas of physics, this might be true. In natural sciences, there have been two main approaches

1. Induction · 2. deduction · Induction

• Sir Francis Bacon: The enquirer might hope to see common patterns among the observations, and these common patterns would point to an explanation, or law of nature.

Deduction

Aristotle : A series of observations point to an inevitable Outcome “All men are mortal. Socrates is a man. Therefore Socrates is mortal.”

Mathematics and in detective work.

Hypotheticodeductive method

Karl Popper “Proof is impossible” Scientists set up the hypotheses hypothesis testing; They seek to refute, or disprove, hypotheses rather than to prove them.

A good Hypothesis

1. hypotheses should be sensible and testable
2. Speculation vs. “Informed deduction”
3. Should be based on observable facts, not the fantasy.

Paradigm shifts

Thomas Kuhn: science shuttles between so-called times of normal science and times of scientific revolution. Scientific revolutions, or paradigm shifts, are when a whole new idea invades an area of science.

An Example of Paradigm shift

The paper by Luis Alvarez and colleagues (1980). The Earth had been hit by a meteorite 65 million years ago, caused the extinction of the dinosaurs and other groups.

Paleontology rendition in Popular culture

Jurassic Park and Walking with Dinosaurs The slow evolution of reconstructions of ancient life over the centuries reflects the growth of paleontology as a discipline.

Paleontology as a science: Steps to understanding

Steps to understanding

1. Earliest fossil finds
2. Fossils as magical stones.
3. Fossils as fossils
4. The idea of extinction
5. The vastness of geological time

Earliest fossil finds

Prehistoric peoples picked up and used them as Ornaments Early Greeks, Xenophanes (576–480 bce) and Herodotus(484–426)

Fossils as magical stones

Roman and medieval times Fossil sharks’ teeth were known as glossopetrae worn as amulets The idea of vis plastica The work of Johann Beringer

Fossils as fossils

The genius of Leonardo da Vinci Nicolaus Steno, true nature of glossopetrae Robert Hooke, descriptions of Fossils using a crude microscope Magical explanations of fossils were debunked

The idea of extinction

Robert Hooke was one of the first to hint at the idea of extinction William Hunter (1768): “American incognitum” Reality of extinction: French natural scientist Georges Cuvier Cuvier : father of comparative anatomy

The vastness of geological time

Sedimentary rocks and their contained fossils document the history of long spans of time. Naming of the geological periods and eras : 1820s and 1830s Stratigraphy is an understanding of geologic time Until the late 18th century, scientists accepted calculations from the Bible that the Earth was only 6000– 8000 years old by dissecting the head of a huge modern shark.

4 Paleontology as a science: Fossils and evolution

Fossil & Evolution:

1. Progressionism and Evolution
2. Darwinian evolution

People want to know where life came from, where humans came from, where the Earth and universe came from. These have been questions in philosophy, religion and science for thousands of years and paleontologists have a key role (seepp. 117–20). Despite the spectacular progress of paleontology, earth sciences and astronomy over the last two centuries, many people with fundamentalist religious beliefs deny all natural explanations of origins – these debates are clearly seen as hugely important.